Fix Seirawan gating at Rook square in PGN castling moves
[xboard.git] / moves.c
diff --git a/moves.c b/moves.c
index 12f9b63..a6b066b 100644 (file)
--- a/moves.c
+++ b/moves.c
@@ -5,7 +5,8 @@
  * Massachusetts.
  *
  * Enhancements Copyright 1992-2001, 2002, 2003, 2004, 2005, 2006,
- * 2007, 2008, 2009 Free Software Foundation, Inc.
+ * 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016 Free
+ * Software Foundation, Inc.
  *
  * Enhancements Copyright 2005 Alessandro Scotti
  *
 #include "config.h"
 
 #include <stdio.h>
+#include <ctype.h>
+#include <stdlib.h>
 #if HAVE_STRING_H
 # include <string.h>
 #else /* not HAVE_STRING_H */
 # include <strings.h>
 #endif /* not HAVE_STRING_H */
 #include "common.h"
-#include "backend.h" 
+#include "backend.h"
 #include "moves.h"
 #include "parser.h"
 
@@ -69,23 +72,34 @@ int BlackPiece P((ChessSquare));
 int SameColor P((ChessSquare, ChessSquare));
 int PosFlags(int index);
 
-extern signed char initialRights[BOARD_FILES]; /* [HGM] all rights enabled, set in InitPosition */
-
-
-int WhitePiece(piece)
-     ChessSquare piece;
+int quickFlag;
+char *pieceDesc[EmptySquare];
+char *defaultDesc[EmptySquare] = {
+ "fmWfceFifmnD", "N", "B", "R", "Q",
+ "F", "A", "BN", "RN", "W", "K",
+ "mRcpR", "N0", "BW", "RF", "gQ",
+ "", "", "QN", "", "N", "",
+ "", "", "", "", "",
+ "", "", "", "", "", "",
+ "", "", "", "", "",
+ "", "", "", "", "", "K"
+};
+
+int
+WhitePiece (ChessSquare piece)
 {
     return (int) piece >= (int) WhitePawn && (int) piece < (int) BlackPawn;
 }
 
-int BlackPiece(piece)
-     ChessSquare piece;
+int
+BlackPiece (ChessSquare piece)
 {
     return (int) piece >= (int) BlackPawn && (int) piece < (int) EmptySquare;
 }
 
-int SameColor(piece1, piece2)
-     ChessSquare piece1, piece2;
+#if 0
+int
+SameColor (ChessSquare piece1, ChessSquare piece2)
 {
     return ((int) piece1 >= (int) WhitePawn &&   /* [HGM] can be > King ! */
             (int) piece1 <  (int) BlackPawn &&
@@ -96,147 +110,80 @@ int SameColor(piece1, piece2)
            (int) piece2 >= (int) BlackPawn &&
             (int) piece2 <  (int) EmptySquare);
 }
+#else
+#define SameColor(piece1, piece2) (piece1 < EmptySquare && piece2 < EmptySquare && (piece1 < BlackPawn) == (piece2 < BlackPawn) || piece1 == DarkSquare || piece2 == DarkSquare)
+#endif
 
-ChessSquare PromoPiece(moveType)
-     ChessMove moveType;
-{
-    switch (moveType) {
-      default:
-       return EmptySquare;
-      case WhitePromotionQueen:
-       return WhiteQueen;
-      case BlackPromotionQueen:
-       return BlackQueen;
-      case WhitePromotionRook:
-       return WhiteRook;
-      case BlackPromotionRook:
-       return BlackRook;
-      case WhitePromotionBishop:
-       return WhiteBishop;
-      case BlackPromotionBishop:
-       return BlackBishop;
-      case WhitePromotionKnight:
-       return WhiteKnight;
-      case BlackPromotionKnight:
-       return BlackKnight;
-      case WhitePromotionKing:
-       return WhiteKing;
-      case BlackPromotionKing:
-       return BlackKing;
-      case WhitePromotionChancellor:
-        return WhiteMarshall;
-      case BlackPromotionChancellor:
-        return BlackMarshall;
-      case WhitePromotionArchbishop:
-        return WhiteAngel;
-      case BlackPromotionArchbishop:
-        return BlackAngel;
-      case WhitePromotionCentaur:
-        return WhiteSilver;
-      case BlackPromotionCentaur:
-        return BlackSilver;
-    }
-}
-
-char pieceToChar[] = {
-                        'P', 'N', 'B', 'R', 'Q', 'F', 'E', 'A', 'C', 'W', 'M', 
+unsigned char pieceToChar[EmptySquare+1] = {
+                        'P', 'N', 'B', 'R', 'Q', 'F', 'E', 'A', 'C', 'W', 'M',
                         'O', 'H', 'I', 'J', 'G', 'D', 'V', 'L', 'S', 'U', 'K',
-                        'p', 'n', 'b', 'r', 'q', 'f', 'e', 'a', 'c', 'w', 'm', 
-                        'o', 'h', 'i', 'j', 'g', 'd', 'v', 'l', 's', 'u', 'k', 
+                        'p', 'n', 'b', 'r', 'q', 'f', 'e', 'a', 'c', 'w', 'm',
+                        'o', 'h', 'i', 'j', 'g', 'd', 'v', 'l', 's', 'u', 'k',
                         'x' };
+unsigned char pieceNickName[EmptySquare];
+int promoPartner[EmptySquare];
+
+char
+PieceToChar (ChessSquare p)
+{
+    int c;
+    if((int)p < 0 || (int)p >= (int)EmptySquare) return('?'); /* [HGM] for safety */
+    c = pieceToChar[(int) p];
+    if(c & 128) c = c & 63 | 64;
+    return c;
+}
 
-char PieceToChar(p)
-     ChessSquare p;
+char
+PieceSuffix (ChessSquare p)
 {
-    if((int)p < 0 || (int)p >= (int)EmptySquare) return('x'); /* [HGM] for safety */
-    return pieceToChar[(int) p];
+    int c;
+    if((int)p < 0 || (int)p >= (int)EmptySquare) return 0; /* [HGM] for safety */
+    c = pieceToChar[(int) p];
+    if(c < 128) return 0;
+    return SUFFIXES[c - 128 >> 6];
 }
 
-int PieceToNumber(p)  /* [HGM] holdings: count piece type, ignoring non-participating piece types */
-     ChessSquare p;
+int
+PieceToNumber (ChessSquare p)  /* [HGM] holdings: count piece type, ignoring non-participating piece types */
 {
     int i=0;
     ChessSquare start = (int)p >= (int)BlackPawn ? BlackPawn : WhitePawn;
 
-    while(start++ != p) if(pieceToChar[(int)start-1] != '.') i++;
+    while(start++ != p) if(pieceToChar[start-1] != '.' && pieceToChar[start-1] != '+') i++;
     return i;
 }
 
-ChessSquare CharToPiece(c)
-     int c;
+ChessSquare
+CharToPiece (int c)
 {
      int i;
+     if(c == '.') return EmptySquare;
+     for(i=0; i< (int) EmptySquare; i++)
+          if(pieceNickName[i] == c) return (ChessSquare) i;
      for(i=0; i< (int) EmptySquare; i++)
           if(pieceToChar[i] == c) return (ChessSquare) i;
      return EmptySquare;
 }
 
-ChessMove PromoCharToMoveType(whiteOnMove, promoChar)
-     int whiteOnMove;
-     int promoChar;
-{      /* [HGM] made dependent on CharToPiece to alow alternate piece letters */
-       ChessSquare piece = CharToPiece(whiteOnMove ? ToUpper(promoChar) : ToLower(promoChar) );
-
-
-       if(promoChar == NULLCHAR) return NormalMove;
-
-       switch(piece) {
-               case WhiteQueen:
-                       return WhitePromotionQueen;
-               case WhiteRook:
-                       return WhitePromotionRook;
-               case WhiteBishop:
-                       return WhitePromotionBishop;
-               case WhiteKnight:
-                       return WhitePromotionKnight;
-               case WhiteKing:
-                       return WhitePromotionKing;
-               case WhiteAngel:
-                       return WhitePromotionArchbishop;
-               case WhiteMarshall:
-                       return WhitePromotionChancellor;
-               case WhiteSilver:
-                       return WhitePromotionCentaur;
-               case BlackQueen:
-                       return BlackPromotionQueen;
-               case BlackRook:
-                       return BlackPromotionRook;
-               case BlackBishop:
-                       return BlackPromotionBishop;
-               case BlackKnight:
-                       return BlackPromotionKnight;
-               case BlackKing:
-                       return BlackPromotionKing;
-               case BlackAngel:
-                       return BlackPromotionArchbishop;
-               case BlackMarshall:
-                       return BlackPromotionChancellor;
-               case BlackSilver:
-                       return BlackPromotionCentaur;
-               default:
-                       // not all promotion implemented yet! Take Queen for those we don't know.
-                       return (whiteOnMove ? WhitePromotionQueen : BlackPromotionQueen);
-       }
-}
-
-void CopyBoard(to, from)
-     Board to, from;
+void
+CopyBoard (Board to, Board from)
 {
     int i, j;
-    
-    for (i = 0; i < BOARD_HEIGHT; i++)
+
+    for (i = 0; i < handSize; i++)
       for (j = 0; j < BOARD_WIDTH; j++)
        to[i][j] = from[i][j];
-    for (j = 0; j < BOARD_FILES-1; j++) // [HGM] gamestate: copy castling rights and ep status
+    for (j = 0; j < BOARD_FILES; j++) // [HGM] gamestate: copy castling rights and ep status
+       to[VIRGIN][j] = from[VIRGIN][j],
        to[CASTLING][j] = from[CASTLING][j];
     to[HOLDINGS_SET] = 0; // flag used in ICS play
 }
 
-int CompareBoards(board1, board2)
-     Board board1, board2;
+int
+CompareBoards (Board board1, Board board2)
 {
     int i, j;
-    
+
     for (i = 0; i < BOARD_HEIGHT; i++)
       for (j = 0; j < BOARD_WIDTH; j++) {
          if (board1[i][j] != board2[i][j])
@@ -245,6 +192,542 @@ int CompareBoards(board1, board2)
     return TRUE;
 }
 
+char defaultName[] = "PNBRQ......................................K"  // white
+                     "pnbrq......................................k"; // black
+char shogiName[]   = "PNBRLS...G.++++++..........................K"  // white
+                     "pnbrls...g.++++++..........................k"; // black
+char xqName[]      = "PH.R.AE..K.C................................"  // white
+                     "ph.r.ae..k.c................................"; // black
+
+char *
+CollectPieceDescriptors ()
+{   // make a line of piece descriptions for use in the PGN Piece tag:
+    // dump all engine defined pieces, and pieces with non-standard names,
+    // but suppress black pieces that are the same as their white counterpart
+    ChessSquare p;
+    static char buf[MSG_SIZ], s[2];
+    char *m, *pieceName = defaultName;
+    int len, c, d;
+    *buf = NULLCHAR;
+    if(!pieceDefs) return "";
+    if(gameInfo.variant == VariantChu) return ""; // for now don't do this for Chu Shogi
+    if(gameInfo.variant == VariantShogi) pieceName = shogiName;
+    if(gameInfo.variant == VariantXiangqi) pieceName = xqName;
+    for(p=WhitePawn; p<EmptySquare; p++) {
+       if((c = pieceToChar[p]) == '.' || c == '~') continue;  // does not participate
+       m = pieceDesc[p]; d = (c == '+' ? pieceToChar[DEMOTED(p)] : c);
+       if(p >= BlackPawn && pieceToChar[BLACK_TO_WHITE p] == (c & ~32)
+             && (c != '+' || pieceToChar[DEMOTED(BLACK_TO_WHITE p)] == d)) {// black member of normal pair
+           char *wm = pieceDesc[BLACK_TO_WHITE p];
+           if(!m && !wm || m && wm && !strcmp(wm, m)) continue;            // moves as a white piece
+       } else                                                              // white or unpaired black
+       if((p < BlackPawn || CharToPiece(d & ~32) != EmptySquare) &&        // white or lone black
+          !pieceDesc[p] /*&& pieceName[p] == c*/) continue; // orthodox piece known by its usual name
+// TODO: listing pieces because of unusual name can only be done if we have accurate Betza of all defaults
+       if(!m) m = defaultDesc[p];
+       if(!m) continue;
+       len = strlen(buf);
+       *s = (d > 128 ? SUFFIXES[d-128>>6] : 0); d = 64 + (d & 63);
+       snprintf(buf+len, MSG_SIZ-len, "%s%s%c%s:%s", len ? ";" : "", c == '+' ? "+" : "", d, s, m);
+    }
+    return buf;
+}
+
+int
+LoadPieceDesc (char *s)
+{
+    ChessSquare piece;
+    static char suf[] = SUFFIXES;
+    char *r, *p, *q = s;
+    int ok = TRUE, promoted, c;
+    while(q && *s) {
+       p = s;
+       q = strchr(s, ';');
+       if(q) *q = 0, s = q+1;
+       if(*p == '+') promoted = 1, p++; else promoted = 0;
+       c = *p++;
+       if(!c) { ok = FALSE; continue; } // bad syntax
+       if(*p && (r = strchr(suf, *p))) c += 64*(r - suf + 1), p++;
+       if(*p++ != ':') { ok = FALSE; continue; } // bad syntax
+       if(!strcmp(p, "(null)")) continue; // handle bug in writing of XBoard 4.8.0
+        piece = CharToPiece(c);
+       if(piece >= EmptySquare) { ok = FALSE; continue; } // non-existent piece
+       if(promoted) {
+           piece = promoPartner[piece];
+           if(pieceToChar[piece] != '+') { ok = FALSE; continue; } // promoted form does not exist
+       }
+       ASSIGN(pieceDesc[piece], p);
+       if(piece < BlackPawn && (pieceToChar[WHITE_TO_BLACK piece] == pieceToChar[piece] + 32 || promoted)) {
+           ASSIGN(pieceDesc[WHITE_TO_BLACK piece], p);
+       }
+       pieceDefs = TRUE;
+       if(q) *q = ';';
+    }
+    return ok;
+}
+
+// [HGM] gen: configurable move generation from Betza notation sent by engine.
+// Some notes about two-leg moves: GenPseudoLegal() works in two modes, depending on whether a 'kill-
+// square has been set: without one is generates all moves, and a global int legNr flags in bits 0 and 1
+// if the move has 1 or 2 legs. Only the marking of squares makes use of this info, by only marking
+// target squares of leg 1 (rejecting null move). A dummy move with MoveType 'FirstLeg' to the relay square
+// is generated, so a cyan marker can be put there, and other functions can ignore such a move. When the
+// user selects this square, it becomes the kill-square. Once a kill-square is set, only 2-leg moves are
+// generated that use that square as relay, plus 1-leg moves, so the 1-leg move that goes to the kill-square
+// can be marked during 2nd-leg entry to terminate the move there. For judging the pseudo-legality of the
+// 2nd leg, the from-square has to be considered empty, although the moving piece is still on it.
+
+Boolean pieceDefs;
+
+//  alphabet      "abcdefghijklmnopqrstuvwxyz"
+char symmetry[] = "FBNW.FFW.NKN.NW.QR....W..N";
+char xStep[]    = "2110.130.102.10.00....0..2";
+char yStep[]    = "2132.133.313.20.11....1..3";
+char dirType[]  = "01000104000200000260050000";
+char upgrade[]  = "AFCD.BGH.JQL.NO.KW....R..Z";
+char rotate[]   = "DRCA.WHG.JKL.NO.QB....F..Z";
+
+//  alphabet   "a b    c d e f    g h    i j k l    m n o p q r    s    t u v    w x y z "
+int dirs1[] = { 0,0x3C,0,0,0,0xC3,0,0,   0,0,0,0xF0,0,0,0,0,0,0x0F,0   ,0,0,0   ,0,0,0,0 };
+int dirs2[] = { 0,0x18,0,0,0,0x81,0,0xFF,0,0,0,0x60,0,0,0,0,0,0x06,0x66,0,0,0x99,0,0,0,0 };
+int dirs3[] = { 0,0x38,0,0,0,0x83,0,0xFF,0,0,0,0xE0,0,0,0,0,0,0x0E,0xEE,0,0,0xBB,0,0,0,0 };
+int dirs4[] = { 0,0x10,0,0,0,0x01,0,0xFF,0,0,0,0x40,0,0,0,0,0,0x04,0x44,0,0,0x11,0,0,0,0 };
+
+int rot[][4] = { // rotation matrices for each direction
+  { 1, 0, 0, 1 },
+  { 0, 1, 1, 0 },
+  { 0, 1,-1, 0 },
+  { 1, 0, 0,-1 },
+  {-1, 0, 0,-1 },
+  { 0,-1,-1, 0 },
+  { 0,-1, 1, 0 },
+  {-1, 0, 0, 1 }
+};
+
+void
+OK (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR cl)
+{
+    (*(int*)cl)++;
+}
+
+void
+MovesFromString (Board board, int flags, int f, int r, int tx, int ty, int angle, int range, char *desc, MoveCallback cb, VOIDSTAR cl)
+{
+    char buf[80], *p = desc, *atom = NULL;
+    int mine, his, dir, bit, occup, i, ep, promoRank = -1;
+    ChessMove promo= NormalMove; ChessSquare pc = board[r][f];
+    if(pc == DarkSquare) return; // this is not a piece, but a 'hole' in the board
+    if(flags & F_WHITE_ON_MOVE) his = 2, mine = 1; else his = 1, mine = 2;
+    if(pc == WhitePawn || pc == WhiteLance) promo = WhitePromotion, promoRank = BOARD_HEIGHT-1; else
+    if(pc == BlackPawn || pc == BlackLance) promo = BlackPromotion, promoRank = 0;
+    while(*p) {                  // more moves to go
+       int expo = -1, dx, dy, x, y, mode, dirSet, ds2=0, retry=0, initial=0, jump=1, skip = 0, all = 0;
+       char *cont = NULL;
+       while(*p == 'i') initial++, desc = ++p;
+       while(islower(*p)) p++;  // skip prefixes
+       if(!isupper(*p)) return; // syntax error: no atom
+       dx = xStep[*p-'A'] - '0';// step vector of atom
+       dy = yStep[*p-'A'] - '0';
+       dirSet = 0;              // build direction set based on atom symmetry
+       switch(symmetry[*p-'A']) {
+         case 'B': expo = 0;    // bishop, slide
+         case 'F': all = 0xAA;  // diagonal atom (degenerate 4-fold)
+                   if(tx >= 0) goto king;        // continuation legs specified in K/Q system!
+                   while(islower(*desc) && (i = dirType[*desc-'a']) != '0') {
+                       int b = dirs1[*desc-'a']; // use wide version
+                       if( islower(desc[1]) &&
+                                ((i | dirType[desc[1]-'a']) & 3) == 3) {   // combinable (perpendicular dim)
+                           b = dirs1[*desc-'a'] & dirs1[desc[1]-'a'];      // intersect wide & perp wide
+                           desc += 2;
+                       } else desc++;
+                       dirSet |= b;
+                   }
+                   dirSet &= 0xAA; if(!dirSet) dirSet = 0xAA;
+                   break;
+         case 'R': expo = 0;    // rook, slide
+         case 'W': all = 0x55;  // orthogonal atom (non-deg 4-fold)
+                   if(tx >= 0) goto king;        // continuation legs specified in K/Q system!
+                   while(islower(*desc) && (dirType[*desc-'a'] & ~4) != '0') dirSet |= dirs2[*desc++-'a'];
+                   dirSet &= 0x55; if(!dirSet) dirSet = 0x55;
+                   dirSet = (dirSet << angle | dirSet >> 8-angle) & 255;   // re-orient direction system
+                   break;
+         case 'N': all = 0xFF;  // oblique atom (degenerate 8-fold)
+                   if(tx >= 0) goto king;        // continuation legs specified in K/Q system!
+                   if(*desc == 'h') {            // chiral direction sets 'hr' and 'hl'
+                       dirSet = (desc[1] == 'r' ? 0x55 :  0xAA); desc += 2;
+                   } else
+                   while(islower(*desc) && (i = dirType[*desc-'a']) != '0') {
+                       int b = dirs2[*desc-'a']; // when alone, use narrow version
+                       if(desc[1] == 'h') b = dirs1[*desc-'a'], desc += 2; // dirs1 is wide version
+                       else if(*desc == desc[1] || islower(desc[1]) && i < '4'
+                               && ((i | dirType[desc[1]-'a']) & 3) == 3) { // combinable (perpendicular dim or same)
+                           b = dirs1[*desc-'a'] & dirs2[desc[1]-'a'];      // intersect wide & perp narrow
+                           desc += 2;
+                       } else desc++;
+                       dirSet |= b;
+                   }
+                   if(!dirSet) dirSet = 0xFF;
+                   break;
+         case 'Q': expo = 0;    // queen, slide
+         case 'K': all = 0xFF;  // non-deg (pseudo) 8-fold
+         king:
+                   while(islower(*desc) && (i = dirType[*desc-'a']) != '0') {
+                       int b = dirs4[*desc-'a'];    // when alone, use narrow version
+                       if(desc[1] == *desc) desc++; // doubling forces alone
+                       else if(islower(desc[1]) && i < '4'
+                               && ((i | dirType[desc[1]-'a']) & 3) == 3) { // combinable (perpendicular dim or same)
+                           b = dirs3[*desc-'a'] & dirs3[desc[1]-'a'];      // intersect wide & perp wide
+                           desc += 2;
+                       } else desc++;
+                       dirSet |= b;
+                   }
+                   if(!dirSet) dirSet = (tx < 0 ? 0xFF                     // default is all directions, but in continuation leg
+                                         : all == 0xFF ? 0xEF : 0x45);     // omits backward, and for 4-fold atoms also diags
+                   dirSet = (dirSet << angle | dirSet >> 8-angle) & 255;   // re-orient direction system
+                   ds2 = dirSet & 0xAA;          // extract diagonal directions
+                   if(dirSet &= 0x55)            // start with orthogonal moves, if present
+                        retry = 1, dx = 0;       // and schedule the diagonal moves for later
+                   else dx = dy, dirSet = ds2;   // if no orthogonal directions, do diagonal immediately
+                   break;       // should not have direction indicators
+         default:  return;      // syntax error: invalid atom
+       }
+       if(mine == 2 && tx < 0) dirSet = dirSet >> 4 | dirSet << 4 & 255;   // invert black moves
+       mode = 0;                // build mode mask
+       if(*desc == 'm') mode |= 4, desc++;           // move to empty
+       if(*desc == 'c') mode |= his, desc++;         // capture foe
+       if(*desc == 'd') mode |= mine, desc++;        // destroy (capture friend)
+       if(*desc == 'e') mode |= 8, desc++;           // e.p. capture last mover
+       if(*desc == 't') mode |= 16, desc++;          // exclude enemies as hop platform ('test')
+       if(*desc == 'p') mode |= 32, desc++;          // hop over occupied
+       if(*desc == 'g') mode |= 64, desc++;          // hop and toggle range
+       if(*desc == 'o') mode |= 128, desc++;         // wrap around cylinder board
+       if(*desc == 'y') mode |= 512, desc++;         // toggle range on empty square
+       if(*desc == 'n') jump = 0, desc++;            // non-jumping
+       while(*desc == 'j') jump++, desc++;           // must jump (on B,R,Q: skip first square)
+       if(*desc == 'a') cont = ++desc;               // move again after doing what preceded it
+       if(isdigit(*++p)) expo = atoi(p++);           // read exponent
+       if(expo > 9) p++;                             // allow double-digit
+       desc = p;                                     // this is start of next move
+       if(initial == 2) { if(board[r][f] != initialPosition[r-2*his+3][f]) continue; initial = 0; } else
+       if(initial && !range) {
+               if(   (board[r][f] != initialPosition[r][f] ||
+                      r == 0              && board[TOUCHED_W] & 1<<f ||
+                      r == BOARD_HEIGHT-1 && board[TOUCHED_B] & 1<<f   )) continue;
+               initial = 0;
+       }
+       if(expo > 0 && dx == 0 && dy == 0) {          // castling indicated by O + number
+           mode |= 1024; dy = 1;
+       }
+       if(expo < 0) expo = 1;                        // use 1 for default
+        if(!cont) {
+           if(!(mode & 15)) mode |= his + 4;         // no mode spec, use default = mc
+       } else {
+           strncpy(buf, cont, 80); cont = buf;       // copy next leg(s), so we can modify
+           atom = buf; while(islower(*atom)) atom++; // skip to atom
+           if(mode & 32) mode ^= 256 + 32;           // in non-final legs 'p' means 'pass through'
+           if(mode & 64 + 512) {
+               mode |= 256;                          // and 'g' too, but converts leaper <-> slider
+               if(mode & 512) mode ^= 0x304;         // and 'y' is m-like 'g'
+               *atom = upgrade[*atom-'A'];           // replace atom, BRQ <-> FWK
+               atom[1] = atom[2] = '\0';             // make sure any old range is stripped off
+               if(expo == 1) atom[1] = '0';          // turn other leapers into riders 
+           }
+           if(!(mode & 0x30F)) mode |= 4;            // and default of this leg = m
+       }
+       if(dy == 1) skip = jump - 1, jump = 1;        // on W & F atoms 'j' = skip first square
+        do {
+         for(dir=0, bit=1; dir<8; dir++, bit += bit) { // loop over directions
+           int i = expo, j = skip, hop = mode, vx, vy, loop = 0;
+           if(!(bit & dirSet)) continue;             // does not move in this direction
+           if(dy != 1 || mode & 1024) j = 0;         // 
+           vx = dx*rot[dir][0] + dy*rot[dir][1];     // rotate step vector
+           vy = dx*rot[dir][2] + dy*rot[dir][3];
+           if(tx < 0) x = f, y = r;                  // start square
+           else      x = tx, y = ty;                 // from previous to-square if continuation
+           do {                                      // traverse ray
+               x += vx; y += vy;                     // step to next square
+               if(y < 0 || y >= BOARD_HEIGHT) break; // vertically off-board: always done
+               if(x <  BOARD_LEFT) { if(mode & 128) x += BOARD_RGHT - BOARD_LEFT, loop++; else break; }
+               if(x >= BOARD_RGHT) { if(mode & 128) x -= BOARD_RGHT - BOARD_LEFT, loop++; else break; }
+               if(j) { j--; continue; }              // skip irrespective of occupation
+               if(board[y][x] == DarkSquare) break;  // black squares are supposed to be off board
+               if(!jump    && board[y - vy + vy/2][x - vx + vx/2] != EmptySquare) break; // blocked
+               if(jump > 1 && board[y - vy + vy/2][x - vx + vx/2] == EmptySquare) break; // no hop
+               if(x == f && y == r && !loop) occup = 4;     else // start square counts as empty (if not around cylinder!)
+               if(board[y][x] < BlackPawn)   occup = 0x101; else
+               if(board[y][x] < EmptySquare) occup = 0x102; else
+                                             occup = 4;
+               if(initial && expo - i + 1 != range) { if(occup == 4) continue; else break; }
+               if(cont) {                            // non-final leg
+                 if(mode&16 && his&occup) occup &= 3;// suppress hopping foe in t-mode
+                 if(occup & mode) {                  // valid intermediate square, do continuation
+                   char origAtom = *atom;
+                   int rg = (expo != 1 ? expo - i + 1 : range);   // pass length of last *slider* leg
+                   if(!(bit & all)) *atom = rotate[*atom - 'A']; // orth-diag interconversion to make direction valid
+                   if(occup & mode & 0x104)          // no side effects, merge legs to one move
+                       MovesFromString(board, flags, f, r, x, y, dir, rg, cont, cb, cl);
+                   if(occup & mode & 3 && (killX < 0 || kill2X < 0 && (legNr > 1 || killX == x && killY == y) ||
+                                           (legNr == 1 ? kill2X == x && kill2Y == y : killX == x && killY == y))) {     // destructive first leg
+                       int cnt = 0;
+                       legNr <<= 1;
+                       MovesFromString(board, flags, f, r, x, y, dir, rg, cont, &OK, &cnt); // count possible continuations
+                       legNr >>= 1;
+                       if(cnt) {                                                            // and if there are
+                           if(legNr & 1 ? killX < 0 : kill2X < 0) cb(board, flags, FirstLeg, r, f, y, x, cl);     // then generate their first leg
+                           legNr <<= 1;
+                           MovesFromString(board, flags, f, r, x, y, dir, rg, cont, cb, cl);
+                           legNr >>= 1;
+                       }
+                   }
+                   *atom = origAtom;        // undo any interconversion
+                 }
+                 if(occup != 4) break;      // occupied squares always terminate the leg
+                 continue;
+               }
+               if(hop & 32+64) { if(occup != 4) { if(hop & 64 && i != 1) i = 2; hop &= 31; } continue; } // hopper
+               ep = board[EP_RANK];
+               if(mode & 8 && occup == 4 && board[EP_FILE] == x && (y == (ep & 127) || y - vy == ep - 128)) { // to e.p. square (or 2nd e.p. square)
+                   cb(board, flags, mine == 1 ? WhiteCapturesEnPassant : BlackCapturesEnPassant, r, f, y, x, cl);
+               }
+               if(mode & 1024) {            // castling
+                   i = 2;                   // kludge to elongate move indefinitely
+                   if(occup == 4) continue; // skip empty squares
+                   if((x == BOARD_LEFT + skip || x > BOARD_LEFT + skip && vx < 0 && board[y][x-1-skip] == DarkSquare)
+                                                                   && board[y][x] == initialPosition[y][x]) { // reached initial corner piece
+                     if(pc != WhiteKing && pc != BlackKing || expo == 1) { // non-royal castling (to be entered as two-leg move via 'Rook')
+                       if(killX < 0) cb(board, flags, FirstLeg,   r, f, y, x, cl); if(killX < f)
+                       legNr <<= 1,  cb(board, flags, NormalMove, r, f, y, f - expo, cl), legNr >>= 1;
+                     } else
+                       cb(board, flags, mine == 1 ? WhiteQueenSideCastle : BlackQueenSideCastle, r, f, y, f - expo, cl);
+                   }
+                   if((x == BOARD_RGHT-1-skip || x < BOARD_RGHT-1-skip && vx > 0 && board[y][x+1+skip] == DarkSquare)
+                                                                   && board[y][x] == initialPosition[y][x]) {
+                     if(pc != WhiteKing && pc != BlackKing || expo == 1) {
+                       if(killX < 0) cb(board, flags, FirstLeg,   r, f, y, x, cl); if(killX > f)
+                       legNr <<= 1,  cb(board, flags, NormalMove, r, f, y, f + expo, cl), legNr >>= 1;
+                     } else
+                       cb(board, flags, mine == 1 ? WhiteKingSideCastle : BlackKingSideCastle, r, f, y, f + expo, cl);
+                   }
+                   break;
+               }
+               if(mode & 16 && (board[y][x] == WhiteKing || board[y][x] == BlackKing)) break; // tame piece, cannot capture royal
+               if(occup & mode) cb(board, flags, y == promoRank ? promo : NormalMove, r, f, y, x, cl); // allowed, generate
+               if(occup != 4) break; // not valid transit square
+           } while(--i);
+         }
+         dx = dy; dirSet = ds2;      // prepare for diagonal moves of K,Q
+       } while(retry-- && ds2);      // and start doing them
+       if(tx >= 0) break;            // don't do other atoms in continuation legs
+    }
+} // next atom
+
+// [HGM] move generation now based on hierarchy of subroutines for rays and combinations of rays
+
+void
+SlideForward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
+{
+  int i, rt, ft = ff;
+  for (i = 1;; i++) {
+      rt = rf + i;
+      if (rt >= BOARD_HEIGHT) break;
+      if (SameColor(board[rf][ff], board[rt][ft])) break;
+      callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
+      if (board[rt][ft] != EmptySquare) break;
+  }
+}
+
+void
+SlideBackward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
+{
+  int i, rt, ft = ff;
+  for (i = 1;; i++) {
+      rt = rf - i;
+      if (rt < 0) break;
+      if (SameColor(board[rf][ff], board[rt][ft])) break;
+      callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
+      if (board[rt][ft] != EmptySquare) break;
+  }
+}
+
+void
+SlideVertical (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
+{
+  SlideForward(board, flags, rf, ff, callback, closure);
+  SlideBackward(board, flags, rf, ff, callback, closure);
+}
+
+void
+SlideSideways (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
+{
+  int i, s, rt = rf, ft;
+  for(s = -1; s <= 1; s+= 2) {
+    for (i = 1;; i++) {
+      ft = ff + i*s;
+      if (ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
+      if (SameColor(board[rf][ff], board[rt][ft])) break;
+      callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
+      if (board[rt][ft] != EmptySquare) break;
+    }
+  }
+}
+
+void
+SlideDiagForward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
+{
+  int i, s, rt, ft;
+  for(s = -1; s <= 1; s+= 2) {
+    for (i = 1;; i++) {
+      rt = rf + i;
+      ft = ff + i * s;
+      if (rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
+      if (SameColor(board[rf][ff], board[rt][ft])) break;
+      callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
+      if (board[rt][ft] != EmptySquare) break;
+    }
+  }
+}
+
+void
+SlideDiagBackward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
+{
+  int i, s, rt, ft;
+  for(s = -1; s <= 1; s+= 2) {
+    for (i = 1;; i++) {
+      rt = rf - i;
+      ft = ff + i * s;
+      if (rt < 0 || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
+      if (SameColor(board[rf][ff], board[rt][ft])) break;
+      callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
+      if (board[rt][ft] != EmptySquare) break;
+    }
+  }
+}
+
+void
+Rook (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
+{
+  SlideVertical(board, flags, rf, ff, callback, closure);
+  SlideSideways(board, flags, rf, ff, callback, closure);
+}
+
+void
+Bishop (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
+{
+  SlideDiagForward(board, flags, rf, ff, callback, closure);
+  SlideDiagBackward(board, flags, rf, ff, callback, closure);
+}
+
+void
+Sting (Board board, int flags, int rf, int ff, int dy, int dx, MoveCallback callback, VOIDSTAR closure)
+{ // Lion-like move of Horned Falcon and Soaring Eagle
+  int ft = ff + dx, rt = rf + dy;
+  if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) return;
+  legNr += 2;
+  if (!SameColor(board[rf][ff], board[rt][ft]))
+    callback(board, flags, killX < 0 && board[rt][ft] != EmptySquare ? FirstLeg : NormalMove, rf, ff, rt, ft, closure);
+  legNr -= 2;
+  ft += dx; rt += dy;
+  if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) return;
+  legNr += 2;
+  if (!SameColor(board[rf][ff], board[rt][ft]))
+    callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
+  if (!SameColor(board[rf][ff], board[rf+dy][ff+dx]))
+    callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
+  legNr -= 2;
+}
+
+void
+StepForward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
+{
+  int ft = ff, rt = rf + 1;
+  if (rt >= BOARD_HEIGHT) return;
+  if (SameColor(board[rf][ff], board[rt][ft])) return;
+  callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
+}
+
+void
+StepBackward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
+{
+  int ft = ff, rt = rf - 1;
+  if (rt < 0) return;
+  if (SameColor(board[rf][ff], board[rt][ft])) return;
+  callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
+}
+
+void
+StepSideways (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
+{
+  int ft, rt = rf;
+  ft = ff + 1;
+  if (!(rt >= BOARD_HEIGHT || ft >= BOARD_RGHT) && !SameColor(board[rf][ff], board[rt][ft]))
+      callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
+  ft = ff - 1;
+  if (!(rt >= BOARD_HEIGHT || ft < BOARD_LEFT) && !SameColor(board[rf][ff], board[rt][ft]))
+      callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
+}
+
+void
+StepDiagForward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
+{
+  int ft, rt = rf + 1;
+  if (rt >= BOARD_HEIGHT) return;
+  ft = ff + 1;
+  if (!(rt >= BOARD_HEIGHT || ft >= BOARD_RGHT) && !SameColor(board[rf][ff], board[rt][ft]))
+      callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
+  ft = ff - 1;
+  if (!(rt >= BOARD_HEIGHT || ft < BOARD_LEFT) && !SameColor(board[rf][ff], board[rt][ft]))
+      callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
+}
+
+void
+StepDiagBackward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
+{
+  int ft, rt = rf - 1;
+  if(rt < 0) return;
+  ft = ff + 1;
+  if (!(rt < 0 || ft >= BOARD_RGHT) && !SameColor(board[rf][ff], board[rt][ft]))
+      callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
+  ft = ff - 1;
+  if (!(rt < 0 || ft < BOARD_LEFT) && !SameColor(board[rf][ff], board[rt][ft]))
+      callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
+}
+
+void
+StepVertical (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
+{
+  StepForward(board, flags, rf, ff, callback, closure);
+  StepBackward(board, flags, rf, ff, callback, closure);
+}
+
+void
+Ferz (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
+{
+  StepDiagForward(board, flags, rf, ff, callback, closure);
+  StepDiagBackward(board, flags, rf, ff, callback, closure);
+}
+
+void
+Wazir (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
+{
+  StepVertical(board, flags, rf, ff, callback, closure);
+  StepSideways(board, flags, rf, ff, callback, closure);
+}
+
+void
+Knight (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
+{
+    int i, j, s, rt, ft;
+    for (i = -1; i <= 1; i += 2)
+       for (j = -1; j <= 1; j += 2)
+           for (s = 1; s <= 2; s++) {
+               rt = rf + i*s;
+               ft = ff + j*(3-s);
+               if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
+                   && ( gameInfo.variant != VariantXiangqi || board[rf+i*(s-1)][ff+j*(2-s)] == EmptySquare)
+                   && !SameColor(board[rf][ff], board[rt][ft]))
+                   callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
+           }
+}
 
 /* Call callback once for each pseudo-legal move in the given
    position, except castling moves. A move is pseudo-legal if it is
@@ -254,32 +737,33 @@ int CompareBoards(board1, board2)
    EP_UNKNOWN if we don't know and want to allow all e.p. captures.
    Promotion moves generated are to Queen only.
 */
-void GenPseudoLegal(board, flags, callback, closure)
-     Board board;
-     int flags;
-     MoveCallback callback;
-     VOIDSTAR closure;
+void
+GenPseudoLegal (Board board, int flags, MoveCallback callback, VOIDSTAR closure, ChessSquare filter)
+// speed: only do moves with this piece type
 {
     int rf, ff;
     int i, j, d, s, fs, rs, rt, ft, m;
     int epfile = (signed char)board[EP_STATUS]; // [HGM] gamestate: extract ep status from board
+    int promoRank = gameInfo.variant == VariantMakruk || gameInfo.variant == VariantGrand || gameInfo.variant == VariantChuChess ? 3 : 1;
 
-    for (rf = 0; rf < BOARD_HEIGHT; rf++) 
+    for (rf = 0; rf < BOARD_HEIGHT; rf++)
       for (ff = BOARD_LEFT; ff < BOARD_RGHT; ff++) {
           ChessSquare piece;
 
-         if (flags & F_WHITE_ON_MOVE) {
-             if (!WhitePiece(board[rf][ff])) continue;
-         } else {
-             if (!BlackPiece(board[rf][ff])) continue;
-         }
+         if(board[rf][ff] == EmptySquare) continue;
+         if ((flags & F_WHITE_ON_MOVE) != (board[rf][ff] < BlackPawn)) continue; // [HGM] speed: wrong color
           m = 0; piece = board[rf][ff];
-          if(PieceToChar(piece) == '~') 
-                 piece = (ChessSquare) ( DEMOTED piece );
-          if(gameInfo.variant == VariantShogi)
+          if(PieceToChar(piece) == '~')
+                 piece = (ChessSquare) ( DEMOTED(piece) );
+          if(filter != EmptySquare && piece != filter) continue;
+          if(pieceDefs && pieceDesc[piece]) { // [HGM] gen: use engine-defined moves
+              MovesFromString(board, flags, ff, rf, -1, -1, 0, 0, pieceDesc[piece], callback, closure);
+              continue;
+          }
+          if(IS_SHOGI(gameInfo.variant))
                  piece = (ChessSquare) ( SHOGI piece );
 
-          switch (piece) {
+          switch ((int)piece) {
             /* case EmptySquare: [HGM] this is nonsense, and conflicts with Shogi cases */
            default:
              /* can't happen ([HGM] except for faries...) */
@@ -306,34 +790,35 @@ void GenPseudoLegal(board, flags, callback, closure)
               }
               if (rf < BOARD_HEIGHT-1 && board[rf + 1][ff] == EmptySquare) {
                  callback(board, flags,
-                          rf == BOARD_HEIGHT-2 ? WhitePromotionQueen : NormalMove,
+                          rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
                           rf, ff, rf + 1, ff, closure);
              }
-             if (rf == 1 && board[2][ff] == EmptySquare &&
+             if (rf <= (BOARD_HEIGHT>>1)-3 && board[rf+1][ff] == EmptySquare && // [HGM] grand: also on 3rd rank on 10-board
                   gameInfo.variant != VariantShatranj && /* [HGM] */
                   gameInfo.variant != VariantCourier  && /* [HGM] */
-                  board[3][ff] == EmptySquare ) {
+                  board[rf+2][ff] == EmptySquare ) {
                       callback(board, flags, NormalMove,
-                               rf, ff, 3, ff, closure);
+                               rf, ff, rf+2, ff, closure);
              }
              for (s = -1; s <= 1; s += 2) {
                   if (rf < BOARD_HEIGHT-1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
                      ((flags & F_KRIEGSPIEL_CAPTURE) ||
                       BlackPiece(board[rf + 1][ff + s]))) {
-                     callback(board, flags, 
-                              rf == BOARD_HEIGHT-2 ? WhitePromotionQueen : NormalMove,
+                     callback(board, flags,
+                              rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
                               rf, ff, rf + 1, ff + s, closure);
                  }
-                 if (rf == BOARD_HEIGHT-4) {
+                 if (rf >= BOARD_HEIGHT+1>>1) {// [HGM] grand: 4th & 5th rank on 10-board
+                     int victimFile = (board[LAST_TO] & 0x40 ? ff + s : board[LAST_TO] & 255);
                       if (ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
-                         (epfile == ff + s || epfile == EP_UNKNOWN) &&
-                          board[BOARD_HEIGHT-4][ff + s] == BlackPawn &&
-                          board[BOARD_HEIGHT-3][ff + s] == EmptySquare) {
+                         (board[EP_FILE] == ff + s || epfile == EP_UNKNOWN) && rf < BOARD_HEIGHT-3 &&
+                          (board[rf][victimFile] == BlackPawn || board[rf][victimFile] == BlackLance) &&
+                          board[rf+1][ff + s] == EmptySquare) {
                          callback(board, flags, WhiteCapturesEnPassant,
-                                  rf, ff, 5, ff + s, closure);
+                                  rf, ff, rf+1, ff + s, closure);
                      }
                  }
-             }             
+             }
              break;
 
            case BlackPawn:
@@ -355,42 +840,42 @@ void GenPseudoLegal(board, flags, callback, closure)
                   break;
               }
              if (rf > 0 && board[rf - 1][ff] == EmptySquare) {
-                 callback(board, flags, 
-                          rf == 1 ? BlackPromotionQueen : NormalMove,
+                 callback(board, flags,
+                          rf <= promoRank ? BlackPromotion : NormalMove,
                           rf, ff, rf - 1, ff, closure);
              }
-             if (rf == BOARD_HEIGHT-2 && board[BOARD_HEIGHT-3][ff] == EmptySquare &&
+             if (rf >= (BOARD_HEIGHT+1>>1)+2 && board[rf-1][ff] == EmptySquare && // [HGM] grand
                   gameInfo.variant != VariantShatranj && /* [HGM] */
                   gameInfo.variant != VariantCourier  && /* [HGM] */
-                 board[BOARD_HEIGHT-4][ff] == EmptySquare) {
+                 board[rf-2][ff] == EmptySquare) {
                  callback(board, flags, NormalMove,
-                          rf, ff, BOARD_HEIGHT-4, ff, closure);
+                          rf, ff, rf-2, ff, closure);
              }
              for (s = -1; s <= 1; s += 2) {
                   if (rf > 0 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
                      ((flags & F_KRIEGSPIEL_CAPTURE) ||
                       WhitePiece(board[rf - 1][ff + s]))) {
-                     callback(board, flags, 
-                              rf == 1 ? BlackPromotionQueen : NormalMove,
+                     callback(board, flags,
+                              rf <= promoRank ? BlackPromotion : NormalMove,
                               rf, ff, rf - 1, ff + s, closure);
                  }
-                 if (rf == 3) {
+                 if (rf < BOARD_HEIGHT>>1) {
+                     int victimFile = (board[LAST_TO] & 0x40 ? ff + s : board[LAST_TO] & 255);
                       if (ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
-                         (epfile == ff + s || epfile == EP_UNKNOWN) &&
-                         board[3][ff + s] == WhitePawn &&
-                         board[2][ff + s] == EmptySquare) {
+                         (board[EP_FILE] == ff + s || epfile == EP_UNKNOWN) && rf > 2 &&
+                         (board[rf][victimFile] == WhitePawn || board[rf][victimFile] == WhiteLance) &&
+                         board[rf-1][ff + s] == EmptySquare) {
                          callback(board, flags, BlackCapturesEnPassant,
-                                  rf, ff, 2, ff + s, closure);
+                                  rf, ff, rf-1, ff + s, closure);
                      }
                  }
-             }             
+             }
              break;
 
             case WhiteUnicorn:
             case BlackUnicorn:
            case WhiteKnight:
            case BlackKnight:
-            mounted:
              for (i = -1; i <= 1; i += 2)
                for (j = -1; j <= 1; j += 2)
                  for (s = 1; s <= 2; s++) {
@@ -421,7 +906,7 @@ void GenPseudoLegal(board, flags, callback, closure)
                       callback(board, flags, NormalMove,
                                rf, ff, rf - 2, ff + s, closure);
                  }
-             }             
+             }
              break;
 
             case WhiteCannon:
@@ -447,98 +932,162 @@ void GenPseudoLegal(board, flags, callback, closure)
 
             /* Gold General (and all its promoted versions) . First do the */
             /* diagonal forward steps, then proceed as normal Wazir        */
+            case SHOGI (PROMO WhitePawn):
+               if(gameInfo.variant == VariantShogi) goto WhiteGold;
+            case SHOGI (PROMO BlackPawn):
+               if(gameInfo.variant == VariantShogi) goto BlackGold;
+            case SHOGI WhiteAxe:
+            case SHOGI BlackAxe:
+               SlideVertical(board, flags, rf, ff, callback, closure);
+               break;
+
+            case SHOGI (PROMO WhiteKnight):
+               if(gameInfo.variant == VariantShogi) goto WhiteGold;
+            case SHOGI WhiteClaw:
+            case SHOGI BlackDrunk:
+            case SHOGI BlackAlfil:
+               Ferz(board, flags, rf, ff, callback, closure);
+               StepSideways(board, flags, rf, ff, callback, closure);
+               StepBackward(board, flags, rf, ff, callback, closure);
+               break;
+
+            case SHOGI (PROMO BlackKnight):
+               if(gameInfo.variant == VariantShogi) goto BlackGold;
+            case SHOGI BlackClaw:
+            case SHOGI WhiteDrunk:
+            case SHOGI WhiteAlfil:
+               Ferz(board, flags, rf, ff, callback, closure);
+               StepSideways(board, flags, rf, ff, callback, closure);
+               StepForward(board, flags, rf, ff, callback, closure);
+               break;
+
+
+            case SHOGI WhiteGnu:
+            case SHOGI BlackGnu:
+               if(gameInfo.variant == VariantShogi) goto BlackGold;
+               SlideVertical(board, flags, rf, ff, callback, closure);
+               Ferz(board, flags, rf, ff, callback, closure);
+               StepSideways(board, flags, rf, ff, callback, closure);
+               break;
+
+            case SHOGI (PROMO WhiteQueen):
+            case SHOGI WhiteTokin:
             case SHOGI WhiteWazir:
-            case SHOGI (PROMOTED WhitePawn):
-            case SHOGI (PROMOTED WhiteKnight):
-            case SHOGI (PROMOTED WhiteQueen):
-            case SHOGI (PROMOTED WhiteFerz):
-             for (s = -1; s <= 1; s += 2) {
-                  if (rf < BOARD_HEIGHT-1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
-                      !SameColor(board[rf][ff], board[rf + 1][ff + s])) {
-                      callback(board, flags, NormalMove,
-                              rf, ff, rf + 1, ff + s, closure);
-                 }
-              }
-              goto finishGold;
+           WhiteGold:
+               StepDiagForward(board, flags, rf, ff, callback, closure);
+               Wazir(board, flags, rf, ff, callback, closure);
+               break;
 
+            case SHOGI (PROMO BlackQueen):
+            case SHOGI BlackTokin:
             case SHOGI BlackWazir:
-            case SHOGI (PROMOTED BlackPawn):
-            case SHOGI (PROMOTED BlackKnight):
-            case SHOGI (PROMOTED BlackQueen):
-            case SHOGI (PROMOTED BlackFerz):
-             for (s = -1; s <= 1; s += 2) {
-                  if (rf > 0 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
-                      !SameColor(board[rf][ff], board[rf - 1][ff + s])) {
-                      callback(board, flags, NormalMove,
-                              rf, ff, rf - 1, ff + s, closure);
-                 }
-             }             
+            BlackGold:
+               StepDiagBackward(board, flags, rf, ff, callback, closure);
+               Wazir(board, flags, rf, ff, callback, closure);
+               break;
 
             case WhiteWazir:
             case BlackWazir:
-            finishGold:
-              for (d = 0; d <= 1; d++)
-                for (s = -1; s <= 1; s += 2) {
-                      rt = rf + s * d;
-                      ft = ff + s * (1 - d);
-                      if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
-                          && !SameColor(board[rf][ff], board[rt][ft]) &&
-                          (gameInfo.variant != VariantXiangqi || InPalace(rt, ft) ) )
-                               callback(board, flags, NormalMove,
-                                        rf, ff, rt, ft, closure);
-                      }
-             break;
+               if(gameInfo.variant == VariantXiangqi) {
+                   int palace = (piece == WhiteWazir ? 1 : BOARD_HEIGHT-2); // Palace center
+                   if(ff <= BOARD_WIDTH/2 && !SameColor(board[rf][ff+1], piece)) callback(board, flags, NormalMove, rf, ff, rf, ff+1, closure);
+                   if(ff >= BOARD_WIDTH/2 && !SameColor(board[rf][ff-1], piece)) callback(board, flags, NormalMove, rf, ff, rf, ff-1, closure);
+                   if(rf >= palace && !SameColor(board[rf-1][ff], piece)) callback(board, flags, NormalMove, rf, ff, rf-1, ff, closure);
+                   if(rf <= palace && !SameColor(board[rf+1][ff], piece)) callback(board, flags, NormalMove, rf, ff, rf+1, ff, closure);
+                   break;
+               }
+               Wazir(board, flags, rf, ff, callback, closure);
+               break;
+
+            case SHOGI WhiteMarshall:
+            case SHOGI BlackMarshall:
+               Ferz(board, flags, rf, ff, callback, closure);
+               for (d = 0; d <= 1; d++)
+                   for (s = -2; s <= 2; s += 4) {
+                       rt = rf + s * d;
+                       ft = ff + s * (1 - d);
+                       if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
+                       if (!SameColor(board[rf][ff], board[rt][ft]) )
+                           callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
+                   }
+               break;
+
+            case SHOGI WhiteAngel:
+            case SHOGI BlackAngel:
+               Wazir(board, flags, rf, ff, callback, closure);
 
             case WhiteAlfil:
             case BlackAlfil:
                 /* [HGM] support Shatranj pieces */
-                for (rs = -1; rs <= 1; rs += 2) 
+                for (rs = -1; rs <= 1; rs += 2)
                   for (fs = -1; fs <= 1; fs += 2) {
                       rt = rf + 2 * rs;
                       ft = ff + 2 * fs;
                       if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
                           && ( gameInfo.variant != VariantXiangqi ||
                                board[rf+rs][ff+fs] == EmptySquare && (2*rf < BOARD_HEIGHT) == (2*rt < BOARD_HEIGHT) )
-                         
+
+                          && !SameColor(board[rf][ff], board[rt][ft]))
+                               callback(board, flags, NormalMove,
+                                        rf, ff, rt, ft, closure);
+                      if(gameInfo.variant == VariantShatranj || gameInfo.variant == VariantCourier ||
+                         gameInfo.variant == VariantChu      || gameInfo.variant == VariantXiangqi) continue; // classical Alfil
+                      rt = rf + rs; // in unknown variant we assume Modern Elephant, which can also do one step
+                      ft = ff + fs;
+                      if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
                           && !SameColor(board[rf][ff], board[rt][ft]))
                                callback(board, flags, NormalMove,
                                         rf, ff, rt, ft, closure);
                  }
+                if(gameInfo.variant == VariantSpartan)
+                   for(fs = -1; fs <= 1; fs += 2) {
+                      ft = ff + fs;
+                      if (!(ft < BOARD_LEFT || ft >= BOARD_RGHT) && board[rf][ft] == EmptySquare)
+                               callback(board, flags, NormalMove, rf, ff, rf, ft, closure);
+                   }
                 break;
 
+            /* Make Dragon-Horse also do Dababba moves outside Shogi, for better disambiguation in variant Fairy */
+           case WhiteCardinal:
+           case BlackCardinal:
+              if(gameInfo.variant == VariantChuChess) goto DragonHorse;
+              for (d = 0; d <= 1; d++) // Dababba moves that Rook cannot do
+                for (s = -2; s <= 2; s += 4) {
+                     rt = rf + s * d;
+                     ft = ff + s * (1 - d);
+                      if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
+                     if (SameColor(board[rf][ff], board[rt][ft])) continue;
+                     callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
+                 }
+
             /* Shogi Dragon Horse has to continue with Wazir after Bishop */
             case SHOGI WhiteCardinal:
             case SHOGI BlackCardinal:
-              m++;
+            case SHOGI WhitePCardinal:
+            case SHOGI BlackPCardinal:
+            DragonHorse:
+               Bishop(board, flags, rf, ff, callback, closure);
+               Wazir(board, flags, rf, ff, callback, closure);
+               break;
 
             /* Capablanca Archbishop continues as Knight                  */
             case WhiteAngel:
             case BlackAngel:
-              m++;
+               Knight(board, flags, rf, ff, callback, closure);
 
             /* Shogi Bishops are ordinary Bishops */
             case SHOGI WhiteBishop:
             case SHOGI BlackBishop:
+            case SHOGI WhitePBishop:
+            case SHOGI BlackPBishop:
            case WhiteBishop:
            case BlackBishop:
-             for (rs = -1; rs <= 1; rs += 2) 
-                for (fs = -1; fs <= 1; fs += 2) 
-                 for (i = 1;; i++) {
-                     rt = rf + (i * rs);
-                     ft = ff + (i * fs);
-                      if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
-                     if (SameColor(board[rf][ff], board[rt][ft])) break;
-                     callback(board, flags, NormalMove,
-                              rf, ff, rt, ft, closure);
-                     if (board[rt][ft] != EmptySquare) break;
-                 }
-                if(m==1) goto mounted;
-                if(m==2) goto finishGold;
-                /* Bishop falls through */
-             break;
+               Bishop(board, flags, rf, ff, callback, closure);
+               break;
 
             /* Shogi Lance is unlike anything, and asymmetric at that */
             case SHOGI WhiteQueen:
+              if(gameInfo.variant == VariantChu) goto doQueen;
               for(i = 1;; i++) {
                       rt = rf + i;
                       ft = ff;
@@ -551,6 +1100,7 @@ void GenPseudoLegal(board, flags, callback, closure)
               break;
 
             case SHOGI BlackQueen:
+              if(gameInfo.variant == VariantChu) goto doQueen;
               for(i = 1;; i++) {
                       rt = rf - i;
                       ft = ff;
@@ -562,110 +1112,121 @@ void GenPseudoLegal(board, flags, callback, closure)
               }
               break;
 
+            /* Make Dragon-King Dababba & Rook-like outside Shogi, for better disambiguation in variant Fairy */
+           case WhiteDragon:
+           case BlackDragon:
+              if(gameInfo.variant == VariantChuChess || gameInfo.variant == VariantSpartan) goto DragonKing;
+              for (d = 0; d <= 1; d++) // Dababba moves that Rook cannot do
+                for (s = -2; s <= 2; s += 4) {
+                     rt = rf + s * d;
+                     ft = ff + s * (1 - d);
+                      if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
+                      if (board[rf+rt>>1][ff+ft>>1] == EmptySquare) continue;
+                     if (SameColor(board[rf][ff], board[rt][ft])) continue;
+                     callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
+                 }
+               Rook(board, flags, rf, ff, callback, closure);
+              break;
+
             /* Shogi Dragon King has to continue as Ferz after Rook moves */
             case SHOGI WhiteDragon:
             case SHOGI BlackDragon:
+            case SHOGI WhitePDragon:
+            case SHOGI BlackPDragon:
+            DragonKing:
+               Rook(board, flags, rf, ff, callback, closure);
+               Ferz(board, flags, rf, ff, callback, closure);
+               break;
               m++;
 
             /* Capablanca Chancellor sets flag to continue as Knight      */
             case WhiteMarshall:
             case BlackMarshall:
-              m++;
+               Rook(board, flags, rf, ff, callback, closure);
+               if(gameInfo.variant == VariantSpartan) // in Spartan Chess Chancellor is used for Dragon King.
+                   Ferz(board, flags, rf, ff, callback, closure);
+               else
+                   Knight(board, flags, rf, ff, callback, closure);
+               break;
+
+            case WhiteTower:
+            case BlackTower:
+                for (d = 0; d <= 1; d++) // Dababba moves
+                  for (s = -2; s <= 2; s += 4) {
+                     rt = rf + s * d;
+                     ft = ff + s * (1 - d);
+                      if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
+                     if (SameColor(board[rf][ff], board[rt][ft])) continue;
+                     callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
+                 }
+               Wazir(board, flags, rf, ff, callback, closure);
+               break;
 
             /* Shogi Rooks are ordinary Rooks */
             case SHOGI WhiteRook:
             case SHOGI BlackRook:
+            case SHOGI WhitePRook:
+            case SHOGI BlackPRook:
            case WhiteRook:
            case BlackRook:
-              for (d = 0; d <= 1; d++)
-                for (s = -1; s <= 1; s += 2)
-                 for (i = 1;; i++) {
-                     rt = rf + (i * s) * d;
-                     ft = ff + (i * s) * (1 - d);
-                      if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
-                     if (SameColor(board[rf][ff], board[rt][ft])) break;
-                     callback(board, flags, NormalMove,
-                              rf, ff, rt, ft, closure);
-                     if (board[rt][ft] != EmptySquare) break;
-                 }
-                if(m==1) goto mounted;
-                if(m==2) goto finishSilver;
-             break;
+               Rook(board, flags, rf, ff, callback, closure);
+               break;
 
            case WhiteQueen:
            case BlackQueen:
-             for (rs = -1; rs <= 1; rs++) 
-               for (fs = -1; fs <= 1; fs++) {
-                   if (rs == 0 && fs == 0) continue;
-                   for (i = 1;; i++) {
-                       rt = rf + (i * rs);
-                       ft = ff + (i * fs);
-                        if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
-                       if (SameColor(board[rf][ff], board[rt][ft])) break;
-                       callback(board, flags, NormalMove,
-                                rf, ff, rt, ft, closure);
-                       if (board[rt][ft] != EmptySquare) break;
-                   }
-               }
-             break;
+            case SHOGI WhiteMother:
+            case SHOGI BlackMother:
+           doQueen:
+               Rook(board, flags, rf, ff, callback, closure);
+               Bishop(board, flags, rf, ff, callback, closure);
+               break;
 
-            /* Shogi Pawn and Silver General: first the Pawn move,    */
-            /* then the General continues like a Ferz                 */
-            case SHOGI WhitePawn:
-            case SHOGI WhiteFerz:
-                  if (rf < BOARD_HEIGHT-1 &&
-                           !SameColor(board[rf][ff], board[rf + 1][ff]) ) 
-                           callback(board, flags, NormalMove,
-                                    rf, ff, rf + 1, ff, closure);
-              if(piece != SHOGI WhitePawn) goto finishSilver;
-              break;
+           case SHOGI WhitePawn:
+               StepForward(board, flags, rf, ff, callback, closure);
+               break;
 
             case SHOGI BlackPawn:
+               StepBackward(board, flags, rf, ff, callback, closure);
+               break;
+
+            case WhiteMan:
+                if(gameInfo.variant != VariantMakruk && gameInfo.variant != VariantASEAN) goto commoner;
+            case SHOGI WhiteFerz:
+               Ferz(board, flags, rf, ff, callback, closure);
+               StepForward(board, flags, rf, ff, callback, closure);
+               break;
+
+            case BlackMan:
+                if(gameInfo.variant != VariantMakruk && gameInfo.variant != VariantASEAN) goto commoner;
             case SHOGI BlackFerz:
-                  if (rf > 0 &&
-                           !SameColor(board[rf][ff], board[rf - 1][ff]) ) 
-                           callback(board, flags, NormalMove,
-                                    rf, ff, rf - 1, ff, closure);
-              if(piece == SHOGI BlackPawn) break;
+               StepBackward(board, flags, rf, ff, callback, closure);
 
             case WhiteFerz:
             case BlackFerz:
-            finishSilver:
+               if(gameInfo.variant == VariantXiangqi && ff != BOARD_WIDTH>>1) {
+                   int rt = (piece == BlackFerz ? BOARD_HEIGHT-2 : 1);
+                   int ft = BOARD_WIDTH>>1;
+                   if(!SameColor(board[rf][ff], board[rt][ft]))
+                       callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
+               } else
                 /* [HGM] support Shatranj pieces */
-                for (rs = -1; rs <= 1; rs += 2) 
-                  for (fs = -1; fs <= 1; fs += 2) {
-                      rt = rf + rs;
-                      ft = ff + fs;
-                      if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
-                      if (!SameColor(board[rf][ff], board[rt][ft]) &&
-                          (gameInfo.variant != VariantXiangqi || InPalace(rt, ft) ) )
-                               callback(board, flags, NormalMove,
-                                        rf, ff, rt, ft, closure);
-                 }
-                break;
+               Ferz(board, flags, rf, ff, callback, closure);
+               break;
 
            case WhiteSilver:
            case BlackSilver:
-               m++; // [HGM] superchess: use for Centaur
-            case WhiteMan:
-            case BlackMan:
+               Knight(board, flags, rf, ff, callback, closure); // [HGM] superchess: use for Centaur
+
+            commoner:
+            case SHOGI WhiteMonarch:
+            case SHOGI BlackMonarch:
             case SHOGI WhiteKing:
             case SHOGI BlackKing:
            case WhiteKing:
            case BlackKing:
-//            walking:
-             for (i = -1; i <= 1; i++)
-               for (j = -1; j <= 1; j++) {
-                   if (i == 0 && j == 0) continue;
-                   rt = rf + i;
-                   ft = ff + j;
-                    if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
-                   if (SameColor(board[rf][ff], board[rt][ft])) continue;
-                   callback(board, flags, NormalMove,
-                            rf, ff, rt, ft, closure);
-               }
-               if(m==1) goto mounted;
-             break;
+               Ferz(board, flags, rf, ff, callback, closure);
+               Wazir(board, flags, rf, ff, callback, closure);
+               break;
 
            case WhiteNightrider:
            case BlackNightrider:
@@ -683,12 +1244,175 @@ void GenPseudoLegal(board, flags, callback, closure)
                     }
                  }
              break;
+
+           Amazon:
+               Bishop(board, flags, rf, ff, callback, closure);
+               Rook(board, flags, rf, ff, callback, closure);
+               Knight(board, flags, rf, ff, callback, closure);
+               break;
+
+           // Use Lance as Berolina / Spartan Pawn.
+           case WhiteLance:
+             if(gameInfo.variant == VariantSuper) goto Amazon;
+             if (rf < BOARD_HEIGHT-1 && BlackPiece(board[rf + 1][ff]))
+                 callback(board, flags,
+                          rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
+                          rf, ff, rf + 1, ff, closure);
+             for (s = -1; s <= 1; s += 2) {
+                 if (rf < BOARD_HEIGHT-1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT && board[rf + 1][ff + s] == EmptySquare)
+                     callback(board, flags,
+                              rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
+                              rf, ff, rf + 1, ff + s, closure);
+                 if (rf == 1 && ff + 2*s >= BOARD_LEFT && ff + 2*s < BOARD_RGHT && board[3][ff + 2*s] == EmptySquare )
+                     callback(board, flags, NormalMove, rf, ff, 3, ff + 2*s, closure);
+             }
+             break;
+
+           case BlackLance:
+             if(gameInfo.variant == VariantSuper) goto Amazon;
+             if (rf > 0 && WhitePiece(board[rf - 1][ff]))
+                 callback(board, flags,
+                          rf <= promoRank ? BlackPromotion : NormalMove,
+                          rf, ff, rf - 1, ff, closure);
+             for (s = -1; s <= 1; s += 2) {
+                 if (rf > 0 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT && board[rf - 1][ff + s] == EmptySquare)
+                     callback(board, flags,
+                              rf <= promoRank ? BlackPromotion : NormalMove,
+                              rf, ff, rf - 1, ff + s, closure);
+                 if (rf == BOARD_HEIGHT-2 && ff + 2*s >= BOARD_LEFT && ff + 2*s < BOARD_RGHT && board[rf-2][ff + 2*s] == EmptySquare )
+                     callback(board, flags, NormalMove, rf, ff, rf-2, ff + 2*s, closure);
+             }
+            break;
+
+            case SHOGI WhiteNothing:
+            case SHOGI BlackNothing:
+            case SHOGI WhiteLion:
+            case SHOGI BlackLion:
+            case WhiteLion:
+            case BlackLion:
+              for(rt = rf - 2; rt <= rf + 2; rt++) for(ft = ff - 2; ft <= ff + 2; ft++) {
+                if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
+                if (!(ff == ft && rf == rt) && SameColor(board[rf][ff], board[rt][ft])) continue;
+                i = (killX >= 0 && (rt-killY)*(rt-killY) + (killX-ft)*(killX-ft) < 3); legNr += 2*i;
+                callback(board, flags, (rt-rf)*(rt-rf) + (ff-ft)*(ff-ft) < 3 && board[rt][ft] != EmptySquare && !i ? FirstLeg : NormalMove,
+                         rf, ff, rt, ft, closure);
+                legNr -= 2*i;
+              }
+              break;
+
+            case SHOGI WhiteDagger:
+            case SHOGI BlackDagger:
+            case SHOGI WhitePDagger:
+            case SHOGI BlackPDagger:
+               SlideSideways(board, flags, rf, ff, callback, closure);
+               StepVertical(board, flags, rf, ff, callback, closure);
+               break;
+
+            case SHOGI WhiteCobra:
+            case SHOGI BlackCobra:
+               StepVertical(board, flags, rf, ff, callback, closure);
+               break;
+
+            case SHOGI (PROMO WhiteFerz):
+               if(gameInfo.variant == VariantShogi) goto WhiteGold;
+            case SHOGI (PROMO BlackFerz):
+               if(gameInfo.variant == VariantShogi) goto BlackGold;
+            case SHOGI WhiteSword:
+            case SHOGI BlackSword:
+            case SHOGI WhitePSword:
+            case SHOGI BlackPSword:
+               SlideVertical(board, flags, rf, ff, callback, closure);
+               StepSideways(board, flags, rf, ff, callback, closure);
+               break;
+
+            case SHOGI WhiteCat:
+            case SHOGI BlackCat:
+               Ferz(board, flags, rf, ff, callback, closure);
+               StepVertical(board, flags, rf, ff, callback, closure);
+               break;
+
+            case SHOGI WhiteCopper:
+               StepDiagForward(board, flags, rf, ff, callback, closure);
+               StepVertical(board, flags, rf, ff, callback, closure);
+               break;
+
+            case SHOGI BlackCopper:
+               StepDiagBackward(board, flags, rf, ff, callback, closure);
+               StepVertical(board, flags, rf, ff, callback, closure);
+               break;
+
+            case SHOGI WhiteHCrown:
+            case SHOGI BlackHCrown:
+               Bishop(board, flags, rf, ff, callback, closure);
+               SlideSideways(board, flags, rf, ff, callback, closure);
+               break;
+
+            case SHOGI WhiteCrown:
+            case SHOGI BlackCrown:
+               Bishop(board, flags, rf, ff, callback, closure);
+               SlideVertical(board, flags, rf, ff, callback, closure);
+               break;
+
+            case SHOGI WhiteUnicorn:
+               Sting(board, flags, rf, ff, 1, 0, callback, closure);
+               callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
+               if(killX >= 0) break;
+               Bishop(board, flags, rf, ff, callback, closure);
+               SlideSideways(board, flags, rf, ff, callback, closure);
+               SlideBackward(board, flags, rf, ff, callback, closure);
+               break;
+
+            case SHOGI BlackUnicorn:
+               Sting(board, flags, rf, ff, -1, 0, callback, closure);
+               callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
+               if(killX >= 0) break;
+               Bishop(board, flags, rf, ff, callback, closure);
+               SlideSideways(board, flags, rf, ff, callback, closure);
+               SlideForward(board, flags, rf, ff, callback, closure);
+               break;
+
+            case SHOGI WhiteFalcon:
+               Sting(board, flags, rf, ff, 1,  1, callback, closure);
+               Sting(board, flags, rf, ff, 1, -1, callback, closure);
+               callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
+               if(killX >= 0) break;
+               Rook(board, flags, rf, ff, callback, closure);
+               SlideDiagBackward(board, flags, rf, ff, callback, closure);
+               break;
+
+            case SHOGI BlackFalcon:
+               Sting(board, flags, rf, ff, -1,  1, callback, closure);
+               Sting(board, flags, rf, ff, -1, -1, callback, closure);
+               callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
+               if(killX >= 0) break;
+               Rook(board, flags, rf, ff, callback, closure);
+               SlideDiagForward(board, flags, rf, ff, callback, closure);
+               break;
+
+            case SHOGI WhiteDolphin:
+            case SHOGI BlackHorse:
+               SlideDiagBackward(board, flags, rf, ff, callback, closure);
+               SlideVertical(board, flags, rf, ff, callback, closure);
+               break;
+
+            case SHOGI BlackDolphin:
+            case SHOGI WhiteHorse:
+               SlideDiagForward(board, flags, rf, ff, callback, closure);
+               SlideVertical(board, flags, rf, ff, callback, closure);
+               break;
+
+            case SHOGI WhiteLance:
+               SlideForward(board, flags, rf, ff, callback, closure);
+               break;
+
+            case SHOGI BlackLance:
+               SlideBackward(board, flags, rf, ff, callback, closure);
+               break;
+
            case WhiteFalcon: // [HGM] wild: for wildcards, self-capture symbolizes move to anywhere
            case BlackFalcon:
            case WhiteCobra:
            case BlackCobra:
-           case WhiteLance:
-           case BlackLance:
              callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
              break;
 
@@ -702,23 +1426,39 @@ typedef struct {
     VOIDSTAR cl;
 } GenLegalClosure;
 
+int rFilter, fFilter; // [HGM] speed: sorry, but I get a bit tired of this closure madness
+Board xqCheckers, nullBoard;
+
 extern void GenLegalCallback P((Board board, int flags, ChessMove kind,
                                int rf, int ff, int rt, int ft,
                                VOIDSTAR closure));
 
-void GenLegalCallback(board, flags, kind, rf, ff, rt, ft, closure)
-     Board board;
-     int flags;
-     ChessMove kind;
-     int rf, ff, rt, ft;
-     VOIDSTAR closure;
+void
+GenLegalCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
 {
     register GenLegalClosure *cl = (GenLegalClosure *) closure;
 
-    if (!(flags & F_IGNORE_CHECK) &&
-       CheckTest(board, flags, rf, ff, rt, ft,
+    if(rFilter >= 0 && rFilter != rt || fFilter >= 0 && fFilter != ft) return; // [HGM] speed: ignore moves with wrong to-square
+
+    if ((int)board[EP_STATUS] == EP_IRON_LION && (board[rt][ft] == WhiteLion || board[rt][ft] == BlackLion)) return; //[HGM] lion
+
+    if (!(flags & F_IGNORE_CHECK) ) {
+      int check, promo = (gameInfo.variant == VariantSpartan && kind == BlackPromotion);
+      if(promo) {
+           int r, f, kings=0;
+           for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT;       f++)
+               kings += (board[r][f] == BlackKing);
+           if(kings >= 2)
+             promo = 0;
+           else
+               board[rf][ff] = BlackKing; // [HGM] spartan: promote to King before check-test
+       }
+       check = CheckTest(board, flags, rf, ff, rt, ft,
                  kind == WhiteCapturesEnPassant ||
-                 kind == BlackCapturesEnPassant)) return;
+                 kind == BlackCapturesEnPassant);
+       if(promo) board[rf][ff] = BlackLance;
+      if(check) return;
+    }
     if (flags & F_ATOMIC_CAPTURE) {
       if (board[rt][ft] != EmptySquare ||
          kind == WhiteCapturesEnPassant || kind == BlackCapturesEnPassant) {
@@ -751,29 +1491,32 @@ typedef struct {
    true if castling is not yet ruled out by a move of the king or
    rook.  Return TRUE if the player on move is currently in check and
    F_IGNORE_CHECK is not set.  [HGM] add castlingRights parameter */
-int GenLegal(board, flags, callback, closure)
-     Board board;
-     int flags;
-     MoveCallback callback;
-     VOIDSTAR closure;
+int
+GenLegal (Board board, int  flags, MoveCallback callback, VOIDSTAR closure, ChessSquare filter)
 {
     GenLegalClosure cl;
-    int ff, ft, k, left, right;
+    int ff, ft, k, left, right, swap;
     int ignoreCheck = (flags & F_IGNORE_CHECK) != 0;
     ChessSquare wKing = WhiteKing, bKing = BlackKing, *castlingRights = board[CASTLING];
+    int inCheck = !ignoreCheck && CheckTest(board, flags, -1, -1, -1, -1, FALSE); // kludge alert: this would mark pre-existing checkers if status==1
+    char *p;
 
     cl.cb = callback;
     cl.cl = closure;
-    GenPseudoLegal(board, flags, GenLegalCallback, (VOIDSTAR) &cl);
+    xqCheckers[EP_STATUS] *= 2; // quasi: if previous CheckTest has been marking, we now set flag for suspending same checkers
+    if(filter == EmptySquare) rFilter = fFilter = -1; // [HGM] speed: do not filter on square if we do not filter on piece
+    GenPseudoLegal(board, flags, GenLegalCallback, (VOIDSTAR) &cl, filter);
 
-    if (!ignoreCheck &&
-       CheckTest(board, flags, -1, -1, -1, -1, FALSE)) return TRUE;
+    if (inCheck) return TRUE;
 
     /* Generate castling moves */
     if(gameInfo.variant == VariantKnightmate) { /* [HGM] Knightmate */
         wKing = WhiteUnicorn; bKing = BlackUnicorn;
     }
 
+    p = (flags & F_WHITE_ON_MOVE ? pieceDesc[wKing] : pieceDesc[bKing]);
+    if(p && strchr(p, 'O')) return FALSE; // [HGM] gen: castlings were already generated from string
+
     for (ff = BOARD_WIDTH>>1; ff >= (BOARD_WIDTH-1)>>1; ff-- /*ics wild 1*/) {
        if ((flags & F_WHITE_ON_MOVE) &&
            (flags & F_WHITE_KCASTLE_OK) &&
@@ -785,7 +1528,7 @@ int GenLegal(board, flags, callback, closure)
             board[0][BOARD_RGHT-1] == WhiteRook &&
             castlingRights[0] != NoRights && /* [HGM] check rights */
             ( castlingRights[2] == ff || castlingRights[6] == ff ) &&
-            (ignoreCheck ||                             
+            (ignoreCheck ||
             (!CheckTest(board, flags, 0, ff, 0, ff + 1, FALSE) &&
               !CheckTest(board, flags, 0, ff, 0, BOARD_RGHT-3, FALSE) &&
               (gameInfo.variant != VariantJanus || !CheckTest(board, flags, 0, ff, 0, BOARD_RGHT-2, FALSE)) &&
@@ -855,10 +1598,11 @@ int GenLegal(board, flags, callback, closure)
        }
     }
 
-  if(gameInfo.variant == VariantFischeRandom) {
+  if((swap = gameInfo.variant == VariantSChess) || flags & F_FRC_TYPE_CASTLING) {
 
     /* generate all potential FRC castling moves (KxR), ignoring flags */
     /* [HGM] test if the Rooks we find have castling rights */
+    /* In S-Chess we generate RxK for allowed castlings, for gating at Rook square */
 
 
     if ((flags & F_WHITE_ON_MOVE) != 0) {
@@ -876,8 +1620,10 @@ int GenLegal(board, flags, callback, closure)
                 if(k != ft && board[0][k] != EmptySquare) ft = NoRights;
             for(k=left; k<right && ft != NoRights; k++) /* then if not checked */
                 if(!ignoreCheck && CheckTest(board, flags, 0, ff, 0, k, FALSE)) ft = NoRights;
-            if(ft != NoRights && board[0][ft] == WhiteRook)
-                callback(board, flags, WhiteHSideCastleFR, 0, ff, 0, ft, closure);
+            if(ft != NoRights && board[0][ft] == WhiteRook) {
+                if(flags & F_FRC_TYPE_CASTLING) callback(board, flags, WhiteHSideCastleFR, 0, ff, 0, ft, closure);
+                if(swap)                        callback(board, flags, WhiteHSideCastleFR, 0, ft, 0, ff, closure);
+            }
 
             ft = castlingRights[1]; /* Rook file if we have A-side rights */
             left  = BOARD_LEFT+2;
@@ -885,11 +1631,14 @@ int GenLegal(board, flags, callback, closure)
             if(ff <= BOARD_LEFT+2) { left = ff+1; right = BOARD_LEFT+3; }
             for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
                 if(k != ft && board[0][k] != EmptySquare) ft = NoRights;
-            if(ff > BOARD_LEFT+2) 
+            if(ft == 0 && ff != 1 && board[0][1] != EmptySquare) ft = NoRights; /* Rook can be blocked on b1 */
+            if(ff > BOARD_LEFT+2)
             for(k=left+1; k<=right && ft != NoRights; k++) /* then if not checked */
                 if(!ignoreCheck && CheckTest(board, flags, 0, ff, 0, k, FALSE)) ft = NoRights;
-            if(ft != NoRights && board[0][ft] == WhiteRook)
-                callback(board, flags, WhiteASideCastleFR, 0, ff, 0, ft, closure);
+            if(ft != NoRights && board[0][ft] == WhiteRook) {
+                if(flags & F_FRC_TYPE_CASTLING) callback(board, flags, WhiteASideCastleFR, 0, ff, 0, ft, closure);
+                if(swap)                        callback(board, flags, WhiteASideCastleFR, 0, ft, 0, ff, closure);
+            }
         }
     } else {
         ff = castlingRights[5]; /* King file if we have any rights */
@@ -902,8 +1651,10 @@ int GenLegal(board, flags, callback, closure)
                 if(k != ft && board[BOARD_HEIGHT-1][k] != EmptySquare) ft = NoRights;
             for(k=left; k<right && ft != NoRights; k++) /* then if not checked */
                 if(!ignoreCheck && CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, k, FALSE)) ft = NoRights;
-            if(ft != NoRights && board[BOARD_HEIGHT-1][ft] == BlackRook)
-                callback(board, flags, BlackHSideCastleFR, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ft, closure);
+            if(ft != NoRights && board[BOARD_HEIGHT-1][ft] == BlackRook) {
+                if(flags & F_FRC_TYPE_CASTLING) callback(board, flags, BlackHSideCastleFR, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ft, closure);
+                if(swap)                        callback(board, flags, BlackHSideCastleFR, BOARD_HEIGHT-1, ft, BOARD_HEIGHT-1, ff, closure);
+            }
 
             ft = castlingRights[4]; /* Rook file if we have A-side rights */
             left  = BOARD_LEFT+2;
@@ -911,11 +1662,14 @@ int GenLegal(board, flags, callback, closure)
             if(ff <= BOARD_LEFT+2) { left = ff+1; right = BOARD_LEFT+3; }
             for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
                 if(k != ft && board[BOARD_HEIGHT-1][k] != EmptySquare) ft = NoRights;
-            if(ff > BOARD_LEFT+2) 
+            if(ft == 0 && ff != 1 && board[BOARD_HEIGHT-1][1] != EmptySquare) ft = NoRights; /* Rook can be blocked on b8 */
+            if(ff > BOARD_LEFT+2)
             for(k=left+1; k<=right && ft != NoRights; k++) /* then if not checked */
                 if(!ignoreCheck && CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, k, FALSE)) ft = NoRights;
-            if(ft != NoRights && board[BOARD_HEIGHT-1][ft] == BlackRook)
-                callback(board, flags, BlackASideCastleFR, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ft, closure);
+            if(ft != NoRights && board[BOARD_HEIGHT-1][ft] == BlackRook) {
+                if(flags & F_FRC_TYPE_CASTLING) callback(board, flags, BlackASideCastleFR, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ft, closure);
+                if(swap)                        callback(board, flags, BlackASideCastleFR, BOARD_HEIGHT-1, ft, BOARD_HEIGHT-1, ff, closure);
+            }
         }
     }
 
@@ -936,16 +1690,19 @@ extern void CheckTestCallback P((Board board, int flags, ChessMove kind,
                                 VOIDSTAR closure));
 
 
-void CheckTestCallback(board, flags, kind, rf, ff, rt, ft, closure)
-     Board board;
-     int flags;
-     ChessMove kind;
-     int rf, ff, rt, ft;
-     VOIDSTAR closure;
+void
+CheckTestCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
 {
     register CheckTestClosure *cl = (CheckTestClosure *) closure;
 
-    if (rt == cl->rking && ft == cl->fking) cl->check++;
+    if (rt == cl->rking && ft == cl->fking) {
+       if((int)xqCheckers[EP_STATUS] >= 2 && xqCheckers[rf][ff]) return; // checker is piece with suspended checking power
+       cl->check++;
+       xqCheckers[rf][ff] = xqCheckers[EP_STATUS] & 1; // remember who is checking (if status == 1)
+    }
+    if( (int)board[EP_STATUS] == EP_ROYAL_LION && (board[rt][ft] == WhiteLion || board[rt][ft] == BlackLion)
+       && (gameInfo.variant != VariantLion || board[rf][ff] != WhiteKing && board[rf][ff] != BlackKing) )
+       cl->check++; // [HGM] lion: forbidden counterstrike against Lion equated to putting yourself in check
 }
 
 
@@ -955,31 +1712,57 @@ void CheckTestCallback(board, flags, kind, rf, ff, rt, ft, closure)
    e.p. capture.  The possibility of castling out of a check along the
    back rank is not accounted for (i.e., we still return nonzero), as
    this is illegal anyway.  Return value is the number of times the
-   king is in check. */ 
-int CheckTest(board, flags, rf, ff, rt, ft, enPassant)
-     Board board;
-     int flags;
-     int rf, ff, rt, ft, enPassant;
+   king is in check. */
+int
+CheckTest (Board board, int flags, int rf, int ff, int rt, int ft, int enPassant)
 {
     CheckTestClosure cl;
     ChessSquare king = flags & F_WHITE_ON_MOVE ? WhiteKing : BlackKing;
-    ChessSquare captured = EmptySquare;
+    ChessSquare captured = EmptySquare, ep=0, trampled=0, trampled2 = 0;
+    int saveKill = killX;
     /*  Suppress warnings on uninitialized variables    */
 
     if(gameInfo.variant == VariantXiangqi)
         king = flags & F_WHITE_ON_MOVE ? WhiteWazir : BlackWazir;
     if(gameInfo.variant == VariantKnightmate)
         king = flags & F_WHITE_ON_MOVE ? WhiteUnicorn : BlackUnicorn;
+    if(gameInfo.variant == VariantChu || gameInfo.variant == VariantShogi) { // strictly speaking this is not needed, as Chu officially has no check
+       int r, f, k = king, royals=0, prince = flags & F_WHITE_ON_MOVE ? WhiteMonarch : BlackMonarch;
+       if(gameInfo.variant == VariantShogi) prince -= 11;                   // White/BlackFalcon
+       for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) {
+           if(board[r][f] == k || board[r][f] == prince) {
+               if(++royals > 1) return FALSE; // no check if we have two royals (ignores double captureby Lion!)
+               king = board[r][f]; // remember hich one we had
+           }
+       }
+    }
+
+    if(PieceToChar(king) == '.') return 0; // never in check if the royal piece does not participate
 
-    if (rf >= 0) {
+    if (rt >= 0) {
        if (enPassant) {
            captured = board[rf][ft];
            board[rf][ft] = EmptySquare;
        } else {
-           captured = board[rt][ft];
+           captured = board[rt][ft];
+           if(killX >= 0) {
+               trampled = board[killY][killX]; board[killY][killX] = EmptySquare; killX = -1; saveKill += (kill2X << 16) + (1 << 30);
+               if(kill2X >= 0) { trampled2 = board[kill2Y][kill2X]; board[kill2Y][kill2X] = EmptySquare; kill2X = -1; }
+           }
+       }
+       if(rf == DROP_RANK) board[rt][ft] = ff; else { // [HGM] drop
+           board[rt][ft] = board[rf][ff];
+           if(rf != rt || ff != ft) board[rf][ff] = EmptySquare;
+       }
+       ep = board[EP_STATUS];
+       if( captured == WhiteLion || captured == BlackLion ) { // [HGM] lion: Chu Lion-capture rules
+           ChessSquare victim = saveKill < 0 ? EmptySquare : trampled;
+           if( (board[rt][ft] == WhiteLion || board[rt][ft] == BlackLion) &&           // capturer is Lion
+               (ff - ft > 1 || ft - ff > 1 || rf - rt > 1 || rt - rf > 1) &&           // captures from a distance
+               (victim == EmptySquare || victim == WhitePawn || victim == BlackPawn    // no or worthless 'bridge'
+                                    || victim == WhiteCobra || victim == BlackCobra) ) // (Pawn or Go Between)
+                    board[EP_STATUS] = EP_ROYAL_LION; // on distant Lion x Lion victim must not be pseudo-legally protected
        }
-       board[rt][ft] = board[rf][ff];
-       board[rf][ff] = EmptySquare;
     }
 
     /* For compatibility with ICS wild 9, we scan the board in the
@@ -999,124 +1782,215 @@ int CheckTest(board, flags, rf, ff, rt, ft, enPassant)
                       board[i][cl.fking] == (dir>0 ? BlackWazir : WhiteWazir) )
                           cl.check++;
               }
-
-             GenPseudoLegal(board, flags ^ F_WHITE_ON_MOVE, CheckTestCallback, (VOIDSTAR) &cl);
-             goto undo_move;  /* 2-level break */
+             GenPseudoLegal(board, flags ^ F_WHITE_ON_MOVE, CheckTestCallback, (VOIDSTAR) &cl, EmptySquare);
+             if(gameInfo.variant != VariantSpartan || cl.check == 0) // in Spartan Chess go on to test if other King is checked too
+                goto undo_move;  /* 2-level break */
          }
       }
 
   undo_move:
 
-    if (rf >= 0) {
-       board[rf][ff] = board[rt][ft];
+    if (rt >= 0) {
+       if(rf != DROP_RANK) // [HGM] drop
+           board[rf][ff] = board[rt][ft];
        if (enPassant) {
            board[rf][ft] = captured;
            board[rt][ft] = EmptySquare;
        } else {
+           if(saveKill >= 0) {
+               if(saveKill & 1<<30) board[kill2Y][kill2X = saveKill >> 16 & 0xFFF] = trampled2;
+               board[killY][killX = saveKill & 0xFFF] = trampled;
+           }
            board[rt][ft] = captured;
        }
+       board[EP_STATUS] = ep;
     }
 
-    return cl.fking < BOARD_RGHT ? cl.check : 1000; // [HGM] atomic: return 1000 if we have no king
+    return cl.fking < BOARD_RGHT ? cl.check : (gameInfo.variant == VariantAtomic)*1000; // [HGM] atomic: return 1000 if we have no king
+}
+
+int
+HasLion (Board board, int flags)
+{
+    int lion = F_WHITE_ON_MOVE & flags ? WhiteLion : BlackLion;
+    int r, f;
+    for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++)
+        if(board[r][f] == lion) return 1;
+    return 0;
 }
 
+ChessMove
+LegalDrop (Board board, int flags, ChessSquare piece, int rt, int ft)
+{   // [HGM] put drop legality testing in separate routine for clarity
+    int n;
+if(appData.debugMode) fprintf(debugFP, "LegalDrop: %d @ %d,%d)\n", piece, ft, rt);
+    if(board[rt][ft] != EmptySquare) return ImpossibleMove; // must drop to empty square
+    n = PieceToNumber(piece);
+    if((gameInfo.holdingsWidth == 0 || (flags & F_WHITE_ON_MOVE ? board[n][BOARD_WIDTH-1] : board[handSize-1-n][0]) != piece)
+       && gameInfo.variant != VariantBughouse) // in bughouse we don't check for availability, because ICS doesn't always tell us
+        return ImpossibleMove; // piece not available
+    if(gameInfo.variant == VariantShogi) { // in Shogi lots of drops are forbidden!
+        if((piece == WhitePawn || piece == WhiteQueen) && rt == BOARD_HEIGHT-1 ||
+           (piece == BlackPawn || piece == BlackQueen) && rt == 0 ||
+            piece == WhiteKnight && rt > BOARD_HEIGHT-3 ||
+            piece == BlackKnight && rt < 2 ) return IllegalMove; // e.g. where dropped piece has no moves
+        if(piece == WhitePawn || piece == BlackPawn) {
+            int r, max = 1 + (BOARD_HEIGHT == 7); // two Pawns per file in Tori!
+            for(r=1; r<BOARD_HEIGHT-1; r++)
+                if(!(max -= (board[r][ft] == piece))) return IllegalMove; // or there already is a Pawn in file
+            // should still test if we mate with this Pawn
+        }
+    } else if(gameInfo.variant == VariantSChess) { // only back-rank drops
+        if (rt != (piece < BlackPawn ? 0 : BOARD_HEIGHT-1)) return IllegalMove;
+    } else {
+        if( (piece == WhitePawn || piece == BlackPawn) &&
+            (rt == 0 || rt == BOARD_HEIGHT -1 ) )
+            return IllegalMove; /* no pawn drops on 1st/8th */
+    }
+if(appData.debugMode) fprintf(debugFP, "LegalDrop: %d @ %d,%d)\n", piece, ft, rt);
+    if (!(flags & F_IGNORE_CHECK) &&
+       CheckTest(board, flags, DROP_RANK, piece, rt, ft, FALSE) ) return IllegalMove;
+    return flags & F_WHITE_ON_MOVE ? WhiteDrop : BlackDrop;
+}
 
 extern void LegalityTestCallback P((Board board, int flags, ChessMove kind,
                                    int rf, int ff, int rt, int ft,
                                    VOIDSTAR closure));
 
-void LegalityTestCallback(board, flags, kind, rf, ff, rt, ft, closure)
-     Board board;
-     int flags;
-     ChessMove kind;
-     int rf, ff, rt, ft;
-     VOIDSTAR closure;
+void
+LegalityTestCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
 {
     register LegalityTestClosure *cl = (LegalityTestClosure *) closure;
 
-//    if (appData.debugMode) {
-//        fprintf(debugFP, "Legality test: %c%c%c%c\n", ff+AAA, rf+ONE, ft+AAA, rt+ONE);
-//    }
     if(board[rt][ft] != EmptySquare || kind==WhiteCapturesEnPassant || kind==BlackCapturesEnPassant)
        cl->captures++; // [HGM] losers: count legal captures
     if (rf == cl->rf && ff == cl->ff && rt == cl->rt && ft == cl->ft)
       cl->kind = kind;
 }
 
-ChessMove LegalityTest(board, flags, rf, ff, rt, ft, promoChar)
-     Board board;
-     int flags;
-     int rf, ff, rt, ft, promoChar;
+ChessMove
+LegalityTest (Board board, int flags, int rf, int ff, int rt, int ft, int promoChar)
 {
-    LegalityTestClosure cl; ChessSquare piece = board[rf][ff], *castlingRights = board[CASTLING];
-    
-    if (appData.debugMode) {
-        int i;
-        for(i=0; i<6; i++) fprintf(debugFP, "%d ", castlingRights[i]);
-        fprintf(debugFP, "Legality test? %c%c%c%c\n", ff+AAA, rf+ONE, ft+AAA, rt+ONE);
-    }
-    /* [HGM] Lance, Cobra and Falcon are wildcard pieces; consider all their moves legal */
+    LegalityTestClosure cl; ChessSquare piece, filterPiece;
+
+    if(quickFlag) flags = flags & ~1 | quickFlag & 1; // [HGM] speed: in quick mode quickFlag specifies side-to-move.
+    if(rf == DROP_RANK) return LegalDrop(board, flags, ff, rt, ft);
+    piece = filterPiece = board[rf][ff];
+    if(PieceToChar(piece) == '~') filterPiece = DEMOTED(piece);
+
+    /* [HGM] Cobra and Falcon are wildcard pieces; consider all their moves legal */
     /* (perhaps we should disallow moves that obviously leave us in check?)              */
-    if(piece == WhiteFalcon || piece == BlackFalcon ||
-       piece == WhiteCobra  || piece == BlackCobra  ||
-       piece == WhiteLance  || piece == BlackLance)
+    if((piece == WhiteFalcon || piece == BlackFalcon ||
+        piece == WhiteCobra  || piece == BlackCobra) && gameInfo.variant != VariantChu && !pieceDesc[piece])
         return CheckTest(board, flags, rf, ff, rt, ft, FALSE) ? IllegalMove : NormalMove;
 
     cl.rf = rf;
     cl.ff = ff;
-    cl.rt = rt;
-    cl.ft = ft;
+    cl.rt = rFilter = rt; // [HGM] speed: filter on to-square
+    cl.ft = fFilter = ft;
     cl.kind = IllegalMove;
     cl.captures = 0; // [HGM] losers: prepare to count legal captures.
-    GenLegal(board, flags, LegalityTestCallback, (VOIDSTAR) &cl);
+    if(flags & F_MANDATORY_CAPTURE) filterPiece = EmptySquare; // [HGM] speed: do not filter in suicide, to find all captures
+    GenLegal(board, flags, LegalityTestCallback, (VOIDSTAR) &cl, filterPiece);
     if((flags & F_MANDATORY_CAPTURE) && cl.captures && board[rt][ft] == EmptySquare
                && cl.kind != WhiteCapturesEnPassant && cl.kind != BlackCapturesEnPassant)
        return(IllegalMove); // [HGM] losers: if there are legal captures, non-capts are illegal
 
+    if(promoChar == 'x') promoChar = NULLCHAR; // [HGM] is this ever the case?
+    if(gameInfo.variant == VariantSChess && promoChar && promoChar != '=' && board[rf][ff] != WhitePawn && board[rf][ff] != BlackPawn) {
+        if(board[rf][ff] < BlackPawn) { // white
+            if(rf != 0) return IllegalMove; // must be on back rank
+            if(!(board[VIRGIN][ff] & VIRGIN_W)) return IllegalMove; // non-virgin
+            if(board[PieceToNumber(CharToPiece(ToUpper(promoChar)))][BOARD_WIDTH-2] == 0) return ImpossibleMove;// must be in stock
+            if(cl.kind == WhiteHSideCastleFR && (ff == BOARD_RGHT-2 || ff == BOARD_RGHT-3)) return ImpossibleMove;
+            if(cl.kind == WhiteASideCastleFR && (ff == BOARD_LEFT+2 || ff == BOARD_LEFT+3)) return ImpossibleMove;
+        } else {
+            if(rf != BOARD_HEIGHT-1) return IllegalMove;
+            if(!(board[VIRGIN][ff] & VIRGIN_B)) return IllegalMove; // non-virgin
+            if(board[BOARD_HEIGHT-1-PieceToNumber(CharToPiece(ToLower(promoChar)))][1] == 0) return ImpossibleMove;
+            if(cl.kind == BlackHSideCastleFR && (ff == BOARD_RGHT-2 || ff == BOARD_RGHT-3)) return ImpossibleMove;
+            if(cl.kind == BlackASideCastleFR && (ff == BOARD_LEFT+2 || ff == BOARD_LEFT+3)) return ImpossibleMove;
+        }
+    } else
+    if(gameInfo.variant == VariantChu) {
+        if(cl.kind != NormalMove || promoChar == NULLCHAR || promoChar == '=') return cl.kind;
+        if(promoChar != '+')
+            return CharToPiece(promoChar) == EmptySquare ? ImpossibleMove : IllegalMove;
+        if(PieceToChar(CHUPROMOTED(board[rf][ff])) != '+') {
+           if(PieceToChar(CHUPROMOTED (board[rf][ff] < BlackPawn ? WhitePawn : BlackPawn)) != '.')
+           return ImpossibleMove;
+       }
+        return flags & F_WHITE_ON_MOVE ? WhitePromotion : BlackPromotion;
+    } else
     if(gameInfo.variant == VariantShogi) {
         /* [HGM] Shogi promotions. '=' means defer */
         if(rf != DROP_RANK && cl.kind == NormalMove) {
             ChessSquare piece = board[rf][ff];
+            int zone = BOARD_HEIGHT/3 + (BOARD_HEIGHT == 8);
 
             if(promoChar == PieceToChar(BlackQueen)) promoChar = NULLCHAR; /* [HGM] Kludge */
-            if(promoChar != NULLCHAR && promoChar != 'x' &&
-               promoChar != '+' && promoChar != '=' &&
-               ToUpper(PieceToChar(PROMOTED piece)) != ToUpper(promoChar) )
-                    cl.kind = IllegalMove;
+            if(promoChar == 'd' && (piece == WhiteRook   || piece == BlackRook)   ||
+               promoChar == 'h' && (piece == WhiteBishop || piece == BlackBishop) ||
+               promoChar == 'g' && (piece <= WhiteFerz || piece <= BlackFerz && piece >= BlackPawn) )
+                  promoChar = '+'; // allowed ICS notations
+if(appData.debugMode)fprintf(debugFP,"SHOGI promoChar = %c\n", promoChar ? promoChar : '-');
+            if(promoChar != NULLCHAR && promoChar != '+' && promoChar != '=')
+                return CharToPiece(promoChar) == EmptySquare ? ImpossibleMove : IllegalMove;
             else if(flags & F_WHITE_ON_MOVE) {
                 if( (int) piece < (int) WhiteWazir &&
-                     (rf > BOARD_HEIGHT-4 || rt > BOARD_HEIGHT-4) ) {
+                     (rf >= BOARD_HEIGHT - zone || rt >= BOARD_HEIGHT - zone) ) {
                     if( (piece == WhitePawn || piece == WhiteQueen) && rt > BOARD_HEIGHT-2 ||
                          piece == WhiteKnight && rt > BOARD_HEIGHT-3) /* promotion mandatory */
-                             cl.kind = promoChar == '=' ? IllegalMove : WhitePromotionKnight;
-                    else /* promotion optional, default is promote */
-                             cl.kind = promoChar == '=' ? NormalMove  : WhitePromotionQueen;
-                   
-                } else cl.kind = (promoChar == NULLCHAR || promoChar == 'x' || promoChar == '=') ?
-                                            NormalMove : IllegalMove;
+                       cl.kind = promoChar == '=' ? IllegalMove : WhitePromotion;
+                    else /* promotion optional, default is defer */
+                       cl.kind = promoChar == '+' ? WhitePromotion : WhiteNonPromotion;
+                } else cl.kind = promoChar == '+' ? IllegalMove : NormalMove;
             } else {
-                if( (int) piece < (int) BlackWazir && (rf < 3 || rt < 3) ) {
+                if( (int) piece < (int) BlackWazir && (rf < zone || rt < zone) ) {
                     if( (piece == BlackPawn || piece == BlackQueen) && rt < 1 ||
                          piece == BlackKnight && rt < 2 ) /* promotion obligatory */
-                             cl.kind = promoChar == '=' ? IllegalMove : BlackPromotionKnight;
-                    else /* promotion optional, default is promote */
-                             cl.kind = promoChar == '=' ? NormalMove  : BlackPromotionQueen;
-
-                } else cl.kind = (promoChar == NULLCHAR || promoChar == 'x' || promoChar == '=') ?
-                                            NormalMove : IllegalMove;
+                       cl.kind = promoChar == '=' ? IllegalMove : BlackPromotion;
+                    else /* promotion optional, default is defer */
+                       cl.kind = promoChar == '+' ? BlackPromotion : BlackNonPromotion;
+                } else cl.kind = promoChar == '+' ? IllegalMove : NormalMove;
             }
         }
     } else
-    if (promoChar != NULLCHAR && promoChar != 'x') {
+    if (promoChar != NULLCHAR) {
+       if(cl.kind == NormalMove && promoChar == '+') { // allow shogi-style promotion is pieceToChar specifies them
+            ChessSquare piece = board[rf][ff];
+            if(piece < BlackPawn ? piece > WhiteMan : piece > BlackMan) return ImpossibleMove; // already promoted
+            // should test if in zone, really
+            if(gameInfo.variant == VariantChuChess && (piece == WhiteKnight || piece == BlackKnight) && HasLion(board, flags))
+                return IllegalMove;
+            if(PieceToChar(PROMOTED(piece)) == '+') return flags & F_WHITE_ON_MOVE ? WhitePromotion : BlackPromotion;
+        } else
        if(promoChar == '=') cl.kind = IllegalMove; else // [HGM] shogi: no deferred promotion outside Shogi
-       if (cl.kind == WhitePromotionQueen || cl.kind == BlackPromotionQueen) {
-           cl.kind = 
-             PromoCharToMoveType((flags & F_WHITE_ON_MOVE) != 0, promoChar);
+       if (cl.kind == WhitePromotion || cl.kind == BlackPromotion) {
+           ChessSquare piece = CharToPiece(flags & F_WHITE_ON_MOVE ? ToUpper(promoChar) : ToLower(promoChar));
+           if(piece == EmptySquare)
+                cl.kind = ImpossibleMove; // non-existing piece
+           if(gameInfo.variant == VariantChuChess && promoChar == 'l' && HasLion(board, flags)) {
+                cl.kind = IllegalMove; // no two Lions
+           } else if(gameInfo.variant == VariantSpartan && cl.kind == BlackPromotion ) {
+               if(promoChar != PieceToChar(BlackKing)) {
+                   if(CheckTest(board, flags, rf, ff, rt, ft, FALSE)) cl.kind = IllegalMove; // [HGM] spartan: only promotion to King was possible
+                   if(piece == BlackLance) cl.kind = ImpossibleMove;
+               } else { // promotion to King allowed only if we do not have two yet
+                   int r, f, kings = 0;
+                   for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) kings += (board[r][f] == BlackKing);
+                   if(kings == 2) cl.kind = IllegalMove;
+               }
+           } else if(piece == WhitePawn && rt == BOARD_HEIGHT-1 ||
+                         piece == BlackPawn && rt == 0) cl.kind = IllegalMove; // cannot stay Pawn on last rank in any variant
+           else if((piece == WhiteUnicorn || piece == BlackUnicorn) && gameInfo.variant == VariantKnightmate)
+             cl.kind = IllegalMove; // promotion to Royal Knight not allowed
+           else if((piece == WhiteKing || piece == BlackKing) && gameInfo.variant != VariantSuicide && gameInfo.variant != VariantGiveaway)
+             cl.kind = IllegalMove; // promotion to King usually not allowed
        } else {
            cl.kind = IllegalMove;
        }
     }
-    /* [HGM] For promotions, 'ToQueen' = optional, 'ToKnight' = mandatory */
     return cl.kind;
 }
 
@@ -1128,12 +2002,8 @@ extern void MateTestCallback P((Board board, int flags, ChessMove kind,
                                int rf, int ff, int rt, int ft,
                                VOIDSTAR closure));
 
-void MateTestCallback(board, flags, kind, rf, ff, rt, ft, closure)
-     Board board;
-     int flags;
-     ChessMove kind;
-     int rf, ff, rt, ft;
-     VOIDSTAR closure;
+void
+MateTestCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
 {
     register MateTestClosure *cl = (MateTestClosure *) closure;
 
@@ -1141,15 +2011,14 @@ void MateTestCallback(board, flags, kind, rf, ff, rt, ft, closure)
 }
 
 /* Return MT_NONE, MT_CHECK, MT_CHECKMATE, or MT_STALEMATE */
-int MateTest(board, flags)
-     Board board;
-     int flags;
+int
+MateTest (Board board, int flags)
 {
     MateTestClosure cl;
     int inCheck, r, f, myPieces=0, hisPieces=0, nrKing=0;
     ChessSquare king = flags & F_WHITE_ON_MOVE ? WhiteKing : BlackKing;
 
-    for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) { 
+    for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) {
         // [HGM] losers: Count pieces and kings, to detect other unorthodox winning conditions
        nrKing += (board[r][f] == king);   // stm has king
         if( board[r][f] != EmptySquare ) {
@@ -1158,7 +2027,6 @@ int MateTest(board, flags)
            else hisPieces++;
        }
     }
-    if(appData.debugMode) fprintf(debugFP, "MateTest: K=%d, my=%d, his=%d\n", nrKing, myPieces, hisPieces);
     switch(gameInfo.variant) { // [HGM] losers: extinction wins
        case VariantShatranj:
                if(hisPieces == 1) return myPieces > 1 ? MT_BARE : MT_DRAW;
@@ -1171,142 +2039,221 @@ int MateTest(board, flags)
                if(myPieces == 1) return MT_BARE;
     }
     cl.count = 0;
-    inCheck = GenLegal(board, flags, MateTestCallback, (VOIDSTAR) &cl);
+    inCheck = GenLegal(board, flags, MateTestCallback, (VOIDSTAR) &cl, EmptySquare);
     // [HGM] 3check: yet to do!
     if (cl.count > 0) {
        return inCheck ? MT_CHECK : MT_NONE;
     } else {
+        if(gameInfo.holdingsWidth && gameInfo.variant != VariantSuper && gameInfo.variant != VariantGreat
+                                 && gameInfo.variant != VariantSChess && gameInfo.variant != VariantGrand) { // drop game
+            int r, f, n, holdings = flags & F_WHITE_ON_MOVE ? BOARD_WIDTH-1 : 0;
+            for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) if(board[r][f] == EmptySquare) // all empty squares
+                for(n=0; n<BOARD_HEIGHT; n++) // all pieces in hand
+                    if(board[n][holdings] != EmptySquare) {
+                        int moveType = LegalDrop(board, flags, board[n][holdings], r, f);
+                        if(moveType == WhiteDrop || moveType == BlackDrop) return (inCheck ? MT_CHECK : MT_NONE); // we have legal drop
+                    }
+        }
        if(gameInfo.variant == VariantSuicide) // [HGM] losers: always stalemate, since no check, but result varies
                return myPieces == hisPieces ? MT_STALEMATE :
                                        myPieces > hisPieces ? MT_STAINMATE : MT_STEALMATE;
        else if(gameInfo.variant == VariantLosers) return inCheck ? MT_TRICKMATE : MT_STEALMATE;
        else if(gameInfo.variant == VariantGiveaway) return MT_STEALMATE; // no check exists, stalemated = win
-                                           
-        return inCheck ? MT_CHECKMATE 
-                      : (gameInfo.variant == VariantXiangqi || gameInfo.variant == VariantShatranj) ? 
+
+        return inCheck ? MT_CHECKMATE
+                      : (gameInfo.variant == VariantXiangqi || gameInfo.variant == VariantShatranj || IS_SHOGI(gameInfo.variant)) ?
                          MT_STAINMATE : MT_STALEMATE;
     }
 }
 
-     
+
 extern void DisambiguateCallback P((Board board, int flags, ChessMove kind,
                                    int rf, int ff, int rt, int ft,
                                    VOIDSTAR closure));
 
-void DisambiguateCallback(board, flags, kind, rf, ff, rt, ft, closure)
-     Board board;
-     int flags;
-     ChessMove kind;
-     int rf, ff, rt, ft;
-     VOIDSTAR closure;
+void
+DisambiguateCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
 {
     register DisambiguateClosure *cl = (DisambiguateClosure *) closure;
     int wildCard = FALSE; ChessSquare piece = board[rf][ff];
+    extern int kifu; // in parser.c
 
     // [HGM] wild: for wild-card pieces rt and rf are dummies
     if(piece == WhiteFalcon || piece == BlackFalcon ||
-       piece == WhiteCobra  || piece == BlackCobra  ||
-       piece == WhiteLance  || piece == BlackLance)
-        wildCard = TRUE;
+       piece == WhiteCobra  || piece == BlackCobra)
+        wildCard = !pieceDefs; // no wildcards when engine defined pieces
 
     if ((cl->pieceIn == EmptySquare || cl->pieceIn == board[rf][ff]
          || PieceToChar(board[rf][ff]) == '~'
-              && cl->pieceIn == (ChessSquare)(DEMOTED board[rf][ff])
+              && cl->pieceIn == (ChessSquare)(DEMOTED(board[rf][ff]))
                                                                       ) &&
        (cl->rfIn == -1 || cl->rfIn == rf) &&
        (cl->ffIn == -1 || cl->ffIn == ff) &&
        (cl->rtIn == -1 || cl->rtIn == rt || wildCard) &&
        (cl->ftIn == -1 || cl->ftIn == ft || wildCard)) {
 
+       if(cl->count && rf == cl->rf && ff == cl->ff && rt == cl->rt && ft == cl->ft) return; // duplicate move
+
+       if(cl->count == 1 && kifu & 0x7E && cl->rfIn == -1 && cl->ffIn == -1) { // traditional Shogi disambiguation required
+           int this = 1, other = 1;
+           if(kifu & 2) this &= (flags & 1 ? rt > rf : rt < rf), other &= (flags & 1 ? cl->rt > cl->rf : cl->rt < cl->rf);
+           if(kifu & 4) this &= (flags & 1 ? rt < rf : rt > rf), other &= (flags & 1 ? cl->rt < cl->rf : cl->rt > cl->rf);
+           if(kifu & 8) this &= (rf == rt), other &= (cl->rt == cl->rf);
+           if(kifu & 0x10) this &= (flags & 1 ? ft <= ff : ft >= ff), other &= (flags & 1 ? cl->ft <= cl->ff : cl->ft >= cl->ff);
+           if(kifu & 0x20) this &= (flags & 1 ? ft >= ff : ft <= ff), other &= (flags & 1 ? cl->ft >= cl->ff : cl->ft <= cl->ff);
+           if(kifu & 0x40) this &= (ft == ff), other &= (cl->ft == cl->ff); // should never be used
+           if(!other) cl->count--; // the old move did not satisfy the requested relative position, erase it
+           if(!this) return;       // the current move does not satisfy the requested relative position, ignore it
+       }
+
        cl->count++;
-        cl->piece = board[rf][ff];
-       cl->rf = rf;
-       cl->ff = ff;
-       cl->rt = wildCard ? cl->rtIn : rt;
-       cl->ft = wildCard ? cl->ftIn : ft;
-       cl->kind = kind;
+       if(cl->count == 1 || board[rt][ft] != EmptySquare) {
+         // [HGM] oneclick: if multiple moves, be sure we remember capture
+         cl->piece = board[rf][ff];
+         cl->rf = rf;
+         cl->ff = ff;
+         cl->rt = wildCard ? cl->rtIn : rt;
+         cl->ft = wildCard ? cl->ftIn : ft;
+         cl->kind = kind;
+       }
+       cl->captures += (board[rt][ft] != EmptySquare); // [HGM] oneclick: count captures
     }
 }
 
-void Disambiguate(board, flags, closure)
-     Board board;
-     int flags;
-     DisambiguateClosure *closure;
+void
+Disambiguate (Board board, int flags, DisambiguateClosure *closure)
 {
     int illegal = 0; char c = closure->promoCharIn;
 
-    closure->count = 0;
+    if(quickFlag) flags = flags & ~1 | quickFlag & 1; // [HGM] speed: in quick mode quickFlag specifies side-to-move.
+    closure->count = closure->captures = 0;
     closure->rf = closure->ff = closure->rt = closure->ft = 0;
     closure->kind = ImpossibleMove;
-    if (appData.debugMode) {
-        fprintf(debugFP, "Disambiguate in:  %d(%d,%d)-(%d,%d) = %d (%c)\n",
-                             closure->pieceIn,closure->ffIn,closure->rfIn,closure->ftIn,closure->rtIn,
-                             closure->promoCharIn, closure->promoCharIn >= ' ' ? closure->promoCharIn : '-');
-    }
-    GenLegal(board, flags, DisambiguateCallback, (VOIDSTAR) closure);
+    rFilter = closure->rtIn; // [HGM] speed: only consider moves to given to-square
+    fFilter = closure->ftIn;
+    if(quickFlag) { // [HGM] speed: try without check test first, because if that is not ambiguous, we are happy
+        GenLegal(board, flags|F_IGNORE_CHECK, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn);
+        if(closure->count > 1) { // gamble did not pay off. retry with check test to resolve ambiguity
+            closure->count = closure->captures = 0;
+            closure->rf = closure->ff = closure->rt = closure->ft = 0;
+            closure->kind = ImpossibleMove;
+            GenLegal(board, flags, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn); // [HGM] speed: only pieces of requested type
+        }
+    } else
+    GenLegal(board, flags, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn); // [HGM] speed: only pieces of requested type
     if (closure->count == 0) {
        /* See if it's an illegal move due to check */
         illegal = 1;
-        GenLegal(board, flags|F_IGNORE_CHECK, DisambiguateCallback, (VOIDSTAR) closure);       
+        GenLegal(board, flags|F_IGNORE_CHECK, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn);
        if (closure->count == 0) {
            /* No, it's not even that */
-    if (appData.debugMode) { int i, j;
-       for(i=BOARD_HEIGHT-1; i>=0; i--) {
-               for(j=0; j<BOARD_WIDTH; j++)
-                       fprintf(debugFP, "%3d", (int) board[i][j]);
-               fprintf(debugFP, "\n");
-       }
-    }
+         if(!appData.testLegality && !pieceDefs && closure->pieceIn != EmptySquare) {
+           int f, r; // if there is only a single piece of the requested type on the board, use that
+           closure->rt = closure->rtIn, closure->ft = closure->ftIn;
+           for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++)
+               if(board[r][f] == closure->pieceIn) closure->count++, closure->rf = r, closure->ff = f;
+           if(closure->count > 1) illegal = 0; // ambiguous
+         }
+         if(closure->count == 0) {
+           if (appData.debugMode) { int i, j;
+               for(i=BOARD_HEIGHT-1; i>=0; i--) {
+                   for(j=0; j<BOARD_WIDTH; j++)
+                       fprintf(debugFP, "%3d", (int) board[i][j]);
+                   fprintf(debugFP, "\n");
+               }
+           }
            return;
+         }
        }
+    } else if(pieceDefs && closure->count > 1 && closure->rtIn >=0) { // [HGM] gen: move is ambiguous under engine-defined rules (and not one-click)
+       DisambiguateClosure spare = *closure;
+        if(gameInfo.variant == VariantXiangqi && closure->pieceIn == EmptySquare && closure->ffIn < 0) {
+            closure->ffIn = closure->ftIn; //closure->pieceIn = (flags & 1 ? BlackPawn : WhitePawn); // forward Pawn push has priority
+            Disambiguate(board, flags, closure);
+            return;
+        }
+       pieceDefs = FALSE; spare.count = 0;     // See if the (erroneous) built-in rules would resolve that
+        GenLegal(board, flags, DisambiguateCallback, (VOIDSTAR) &spare, closure->pieceIn);
+       if(spare.count == 1) *closure = spare;  // It does, so use those in stead (game from file saved before gen patch?)
+       pieceDefs = TRUE;
     }
 
+    if (c == 'x') c = NULLCHAR; // get rid of any 'x' (which should never happen?)
+    if(gameInfo.variant == VariantSChess && c && c != '=' && closure->piece != WhitePawn && closure->piece != BlackPawn) {
+        if(closure->piece < BlackPawn) { // white
+            if(closure->rf != 0) closure->kind = IllegalMove; // must be on back rank
+            if(!(board[VIRGIN][closure->ff] & VIRGIN_W)) closure->kind = IllegalMove; // non-virgin
+            if(board[PieceToNumber(CharToPiece(ToUpper(c)))][BOARD_WIDTH-2] == 0) closure->kind = ImpossibleMove;// must be in stock
+            if(closure->kind == WhiteHSideCastleFR && (closure->ff == BOARD_RGHT-2 || closure->ff == BOARD_RGHT-3)) closure->kind = ImpossibleMove;
+            if(closure->kind == WhiteASideCastleFR && (closure->ff == BOARD_LEFT+2 || closure->ff == BOARD_LEFT+3)) closure->kind = ImpossibleMove;
+        } else {
+            if(closure->rf != BOARD_HEIGHT-1) closure->kind = IllegalMove;
+            if(!(board[VIRGIN][closure->ff] & VIRGIN_B)) closure->kind = IllegalMove; // non-virgin
+            if(board[BOARD_HEIGHT-1-PieceToNumber(CharToPiece(ToLower(c)))][1] == 0) closure->kind = ImpossibleMove;
+            if(closure->kind == BlackHSideCastleFR && (closure->ff == BOARD_RGHT-2 || closure->ff == BOARD_RGHT-3)) closure->kind = ImpossibleMove;
+            if(closure->kind == BlackASideCastleFR && (closure->ff == BOARD_LEFT+2 || closure->ff == BOARD_LEFT+3)) closure->kind = ImpossibleMove;
+        }
+    } else
+    if(gameInfo.variant == VariantChu) {
+        if(c == '+') closure->kind = (flags & F_WHITE_ON_MOVE ? WhitePromotion : BlackPromotion); // for now, accept any
+    } else
     if(gameInfo.variant == VariantShogi) {
-        /* [HGM] Shogi promotions. '=' means defer */
+        /* [HGM] Shogi promotions. On input, '=' means defer, '+' promote. Afterwards, c is set to '+' for promotions, NULL other */
         if(closure->rfIn != DROP_RANK && closure->kind == NormalMove) {
             ChessSquare piece = closure->piece;
-            if(c != NULLCHAR && c != 'x' && c != '+' && c != '=' &&
-               ToUpper(PieceToChar(PROMOTED piece)) != ToUpper(c) ) 
-                    closure->kind = IllegalMove;
+            int zone = BOARD_HEIGHT/3 + (BOARD_HEIGHT == 8);
+            if (c == 'd' && (piece == WhiteRook   || piece == BlackRook)   ||
+                c == 'h' && (piece == WhiteBishop || piece == BlackBishop) ||
+                c == 'g' && (piece <= WhiteFerz || piece <= BlackFerz && piece >= BlackPawn) )
+                   c = '+'; // allowed ICS notations
+            if(c != NULLCHAR && c != '+' && c != '=') closure->kind = IllegalMove; // otherwise specifying a piece is illegal
             else if(flags & F_WHITE_ON_MOVE) {
                 if( (int) piece < (int) WhiteWazir &&
-                     (closure->rf > BOARD_HEIGHT-4 || closure->rt > BOARD_HEIGHT-4) ) {
+                     (closure->rf >= BOARD_HEIGHT-zone || closure->rt >= BOARD_HEIGHT-zone) ) {
                     if( (piece == WhitePawn || piece == WhiteQueen) && closure->rt > BOARD_HEIGHT-2 ||
                          piece == WhiteKnight && closure->rt > BOARD_HEIGHT-3) /* promotion mandatory */
-                             closure->kind = c == '=' ? IllegalMove : WhitePromotionKnight;
-                    else /* promotion optional, default is promote */
-                             closure->kind = c == '=' ? NormalMove  : WhitePromotionQueen;
-                   
-                } else closure->kind = (c == NULLCHAR || c == 'x' || c == '=') ?
-                                            NormalMove : IllegalMove;
+                       closure->kind = c == '=' ? IllegalMove : WhitePromotion;
+                    else /* promotion optional, default is defer */
+                       closure->kind = c == '+' ? WhitePromotion : WhiteNonPromotion;
+                } else closure->kind = c == '+' ? IllegalMove : NormalMove;
             } else {
-                if( (int) piece < (int) BlackWazir && (closure->rf < 3 || closure->rt < 3) ) {
+                if( (int) piece < (int) BlackWazir && (closure->rf < zone || closure->rt < zone) ) {
                     if( (piece == BlackPawn || piece == BlackQueen) && closure->rt < 1 ||
                          piece == BlackKnight && closure->rt < 2 ) /* promotion obligatory */
-                             closure->kind = c == '=' ? IllegalMove : BlackPromotionKnight;
-                    else /* promotion optional, default is promote */
-                             closure->kind = c == '=' ? NormalMove  : BlackPromotionQueen;
-
-                } else closure->kind = (c == NULLCHAR || c == 'x' || c == '=') ?
-                                            NormalMove : IllegalMove;
+                       closure->kind = c == '=' ? IllegalMove : BlackPromotion;
+                    else /* promotion optional, default is defer */
+                       closure->kind = c == '+' ? BlackPromotion : BlackNonPromotion;
+                } else closure->kind = c == '+' ? IllegalMove : NormalMove;
             }
         }
+        if(closure->kind == WhitePromotion || closure->kind == BlackPromotion) c = '+'; else
+        if(closure->kind == WhiteNonPromotion || closure->kind == BlackNonPromotion) c = '=';
     } else
-    if (closure->promoCharIn != NULLCHAR && closure->promoCharIn != 'x') {
-       if (closure->kind == WhitePromotionQueen
-           || closure->kind == BlackPromotionQueen) {
-           closure->kind = 
-             PromoCharToMoveType((flags & F_WHITE_ON_MOVE) != 0,
-                                 closure->promoCharIn);
-       } else {
-           closure->kind = IllegalMove;
-       }
-    }
-    /* [HGM] returns 'q' for optional promotion, 'n' for mandatory */
-    if(closure->promoCharIn != '=')
-        closure->promoChar = ToLower(closure->promoCharIn);
-    else closure->promoChar = '=';
-    if (closure->promoChar == 'x') closure->promoChar = NULLCHAR;
+    if (closure->kind == WhitePromotion || closure->kind == BlackPromotion) {
+        if(c == NULLCHAR) { // missing promoChar on mandatory promotion; use default for variant
+            if(gameInfo.variant == VariantShatranj || gameInfo.variant == VariantCourier ||
+               gameInfo.variant == VariantMakruk)
+                c = PieceToChar(BlackFerz);
+            else if(gameInfo.variant == VariantASEAN)
+                c = PieceToChar(BlackRook);
+            else if(gameInfo.variant == VariantGreat)
+                c = PieceToChar(BlackMan);
+            else if(gameInfo.variant == VariantGrand)
+                   closure->kind = closure->rt != 0 && closure->rt != BOARD_HEIGHT-1 ? NormalMove : AmbiguousMove; // no default in Grand Chess
+            else
+                c = PieceToChar(BlackQueen);
+        } else if(c == '=') closure->kind = IllegalMove; // no deferral outside Shogi
+        else if(c == 'l' && gameInfo.variant == VariantChuChess && HasLion(board, flags)) closure->kind = IllegalMove;
+    } else if (c == '+') { // '+' outside shogi, check if pieceToCharTable enabled it
+        ChessSquare p = closure->piece;
+        if(p > WhiteMan && p < BlackPawn || p > BlackMan || PieceToChar(PROMOTED(p)) != '+')
+            closure->kind = ImpossibleMove; // used on non-promotable piece
+        else if(gameInfo.variant == VariantChuChess && HasLion(board, flags)) closure->kind = IllegalMove;
+    } else if (c != NULLCHAR) closure->kind = IllegalMove;
+
+    closure->promoChar = ToLower(c); // this can be NULLCHAR! Note we keep original promoChar even if illegal.
+    if(c != '+' && c != '=' && c != NULLCHAR && CharToPiece(flags & F_WHITE_ON_MOVE ? ToUpper(c) : ToLower(c)) == EmptySquare)
+       closure->kind = ImpossibleMove; // but we cannot handle non-existing piece types!
     if (closure->count > 1) {
        closure->kind = AmbiguousMove;
     }
@@ -1317,14 +2264,6 @@ void Disambiguate(board, flags, closure)
        */
        closure->kind = IllegalMove;
     }
-    if(closure->kind == IllegalMove)
-    /* [HGM] might be a variant we don't understand, pass on promotion info */
-        closure->promoChar = ToLower(closure->promoCharIn);
-    if (appData.debugMode) {
-        fprintf(debugFP, "Disambiguate out: %d(%d,%d)-(%d,%d) = %d (%c)\n",
-        closure->piece,closure->ff,closure->rf,closure->ft,closure->rt,closure->promoChar,
-       closure->promoChar >= ' ' ? closure->promoChar:'-');
-    }
 }
 
 
@@ -1343,20 +2282,16 @@ extern void CoordsToAlgebraicCallback P((Board board, int flags,
                                         ChessMove kind, int rf, int ff,
                                         int rt, int ft, VOIDSTAR closure));
 
-void CoordsToAlgebraicCallback(board, flags, kind, rf, ff, rt, ft, closure)
-     Board board;
-     int flags;
-     ChessMove kind;
-     int rf, ff, rt, ft;
-     VOIDSTAR closure;
+void
+CoordsToAlgebraicCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
 {
     register CoordsToAlgebraicClosure *cl =
       (CoordsToAlgebraicClosure *) closure;
 
-    if (rt == cl->rt && ft == cl->ft &&
+    if ((rt == cl->rt && ft == cl->ft || rt == rf && ft == ff) && // [HGM] null move matches any toSquare
         (board[rf][ff] == cl->piece
          || PieceToChar(board[rf][ff]) == '~' &&
-            (ChessSquare) (DEMOTED board[rf][ff]) == cl->piece)
+            (ChessSquare) (DEMOTED(board[rf][ff])) == cl->piece)
                                      ) {
        if (rf == cl->rf) {
            if (ff == cl->ff) {
@@ -1370,26 +2305,23 @@ void CoordsToAlgebraicCallback(board, flags, kind, rf, ff, rt, ft, closure)
            } else {
                cl->either++; /* rank or file will rule out this move */
            }
-       }           
+       }
     }
 }
 
 /* Convert coordinates to normal algebraic notation.
    promoChar must be NULLCHAR or 'x' if not a promotion.
 */
-ChessMove CoordsToAlgebraic(board, flags, rf, ff, rt, ft, promoChar, out)
-     Board board;
-     int flags;
-     int rf, ff, rt, ft;
-     int promoChar;
-     char out[MOVE_LEN];
+ChessMove
+CoordsToAlgebraic (Board board, int flags, int rf, int ff, int rt, int ft, int promoChar, char out[MOVE_LEN])
 {
     ChessSquare piece;
     ChessMove kind;
-    char *outp = out, c;
+    char *outp = out, c, capture;
     CoordsToAlgebraicClosure cl;
-    
+
     if (rf == DROP_RANK) {
+       if(ff == EmptySquare) { strncpy(outp, "--",3); return NormalMove; } // [HGM] pass
        /* Bughouse piece drop */
        *outp++ = ToUpper(PieceToChar((ChessSquare) ff));
        *outp++ = '@';
@@ -1403,10 +2335,8 @@ ChessMove CoordsToAlgebraic(board, flags, rf, ff, rt, ft, promoChar, out)
 
     if (promoChar == 'x') promoChar = NULLCHAR;
     piece = board[rf][ff];
-    if(PieceToChar(piece)=='~') piece = (ChessSquare)(DEMOTED piece);
+    if(PieceToChar(piece)=='~') piece = (ChessSquare)(DEMOTED(piece));
 
-  if (appData.debugMode)
-          fprintf(debugFP, "CoordsToAlgebraic, piece=%d (%d,%d)-(%d,%d) %c\n", (int)piece,ff,rf,ft,rt,promoChar >= ' ' ? promoChar : '-');
     switch (piece) {
       case WhitePawn:
       case BlackPawn:
@@ -1420,14 +2350,15 @@ ChessMove CoordsToAlgebraic(board, flags, rf, ff, rt, ft, promoChar, out)
        }
        /* Pawn move */
         *outp++ = ff + AAA;
-        if (ff == ft && board[rt][ft] == EmptySquare) { /* [HGM] Xiangqi has straight noncapts! */
+       capture = board[rt][ft] != EmptySquare || kind == WhiteCapturesEnPassant || kind == BlackCapturesEnPassant;
+        if (ff == ft && !capture) { /* [HGM] Xiangqi has straight noncapts! */
            /* Non-capture; use style "e5" */
             if(rt+ONE <= '9')
                *outp++ = rt + ONE;
             else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
        } else {
            /* Capture; use style "exd5" */
-            if(gameInfo.variant != VariantXiangqi || board[rt][ft] != EmptySquare )
+            if(capture)
             *outp++ = 'x';  /* [HGM] Xiangqi has sideway noncaptures across river! */
             *outp++ = ft + AAA;
             if(rt+ONE <= '9')
@@ -1436,10 +2367,8 @@ ChessMove CoordsToAlgebraic(board, flags, rf, ff, rt, ft, promoChar, out)
        }
        /* Use promotion suffix style "=Q" */
        *outp = NULLCHAR;
-  if (appData.debugMode)
-          fprintf(debugFP, "movetype=%d, promochar=%d=%c\n", (int)kind, promoChar, promoChar >= ' ' ? promoChar : '-');
         if (promoChar != NULLCHAR) {
-            if(gameInfo.variant == VariantShogi) {
+            if(IS_SHOGI(gameInfo.variant)) {
                 /* [HGM] ... but not in Shogi! */
                 *outp++ = promoChar == '=' ? '=' : '+';
             } else {
@@ -1450,27 +2379,31 @@ ChessMove CoordsToAlgebraic(board, flags, rf, ff, rt, ft, promoChar, out)
        }
         return kind;
 
-       
+
       case WhiteKing:
       case BlackKing:
         /* Fabien moved code: FRC castling first (if KxR), wild castling second */
        /* Code added by Tord:  FRC castling. */
        if((piece == WhiteKing && board[rt][ft] == WhiteRook) ||
           (piece == BlackKing && board[rt][ft] == BlackRook)) {
-         if(ft > ff) strcpy(out, "O-O"); else strcpy(out, "O-O-O");
-            return LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
+         if(ft > ff)
+           safeStrCpy(out, "O-O", MOVE_LEN);
+         else
+           safeStrCpy(out, "O-O-O", MOVE_LEN);
+         return LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
        }
        /* End of code added by Tord */
        /* Test for castling or ICS wild castling */
        /* Use style "O-O" (oh-oh) for PGN compatibility */
        else if (rf == rt &&
            rf == ((piece == WhiteKing) ? 0 : BOARD_HEIGHT-1) &&
+            (ft - ff > 1 || ff - ft > 1) &&  // No castling if legal King move (on narrow boards!)
             ((ff == BOARD_WIDTH>>1 && (ft == BOARD_LEFT+2 || ft == BOARD_RGHT-2)) ||
              (ff == (BOARD_WIDTH-1)>>1 && (ft == BOARD_LEFT+1 || ft == BOARD_RGHT-3)))) {
             if(ft==BOARD_LEFT+1 || ft==BOARD_RGHT-2)
-               strcpy(out, "O-O");
+             snprintf(out, MOVE_LEN, "O-O%c%c%c", promoChar ? '/' : 0, ToUpper(promoChar), ff + AAA);
             else
-               strcpy(out, "O-O-O");
+             snprintf(out, MOVE_LEN, "O-O-O%c%c%c", promoChar ? '/' : 0, ToUpper(promoChar), ff + AAA);
 
            /* This notation is always unambiguous, unless there are
               kings on both the d and e files, with "wild castling"
@@ -1488,18 +2421,19 @@ ChessMove CoordsToAlgebraic(board, flags, rf, ff, rt, ft, promoChar, out)
        /* Piece move */
        cl.rf = rf;
        cl.ff = ff;
-       cl.rt = rt;
-       cl.ft = ft;
+       cl.rt = rFilter = rt; // [HGM] speed: filter on to-square
+       cl.ft = fFilter = ft;
        cl.piece = piece;
        cl.kind = IllegalMove;
        cl.rank = cl.file = cl.either = 0;
-        GenLegal(board, flags, CoordsToAlgebraicCallback, (VOIDSTAR) &cl);
+        c = PieceToChar(piece) ;
+        GenLegal(board, flags, CoordsToAlgebraicCallback, (VOIDSTAR) &cl, c!='~' ? piece : (DEMOTED(piece))); // [HGM] speed
 
        if (cl.kind == IllegalMove && !(flags&F_IGNORE_CHECK)) {
            /* Generate pretty moves for moving into check, but
               still return IllegalMove.
            */
-            GenLegal(board, flags|F_IGNORE_CHECK, CoordsToAlgebraicCallback, (VOIDSTAR) &cl);
+            GenLegal(board, flags|F_IGNORE_CHECK, CoordsToAlgebraicCallback, (VOIDSTAR) &cl, c!='~' ? piece : (DEMOTED(piece)));
            if (cl.kind == IllegalMove) break;
            cl.kind = IllegalMove;
        }
@@ -1509,13 +2443,13 @@ ChessMove CoordsToAlgebraic(board, flags, rf, ff, rt, ft, promoChar, out)
           else "N1f3" or "N5xf7",
           else "Ng1f3" or "Ng5xf7".
        */
-        c = PieceToChar(piece) ;
         if( c == '~' || c == '+') {
            /* [HGM] print nonexistent piece as its demoted version */
-           piece = (ChessSquare) (DEMOTED piece);
+           piece = (ChessSquare) (CHUDEMOTED(piece));
         }
         if(c=='+') *outp++ = c;
         *outp++ = ToUpper(PieceToChar(piece));
+        if(*outp = PieceSuffix(piece)) outp++;
 
        if (cl.file || (cl.either && !cl.rank)) {
             *outp++ = ff + AAA;
@@ -1533,60 +2467,37 @@ ChessMove CoordsToAlgebraic(board, flags, rf, ff, rt, ft, promoChar, out)
         if(rt+ONE <= '9')
            *outp++ = rt + ONE;
         else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
-       *outp = NULLCHAR;
-        if (gameInfo.variant == VariantShogi) {
+        if (IS_SHOGI(gameInfo.variant)) {
             /* [HGM] in Shogi non-pawns can promote */
-            if(flags & F_WHITE_ON_MOVE) {
-                if( (int) cl.piece < (int) WhiteWazir &&
-                     (rf > BOARD_HEIGHT-4 || rt > BOARD_HEIGHT-4) ) {
-                    if( (piece == WhitePawn || piece == WhiteQueen) && rt > BOARD_HEIGHT-2 ||
-                         piece == WhiteKnight && rt > BOARD_HEIGHT-3) /* promotion mandatory */
-                             cl.kind = promoChar == '=' ? IllegalMove : WhitePromotionKnight;
-                    else cl.kind =  WhitePromotionQueen; /* promotion optional */
-                   
-                } else cl.kind = (promoChar == NULLCHAR || promoChar == 'x' || promoChar == '=') ?
-                                            NormalMove : IllegalMove;
-            } else {
-                if( (int) cl.piece < (int) BlackWazir && (rf < 3 || rt < 3) ) {
-                    if( (piece == BlackPawn || piece == BlackQueen) && rt < 1 ||
-                         piece == BlackKnight && rt < 2 ) /* promotion obligatory */
-                             cl.kind = promoChar == '=' ? IllegalMove : BlackPromotionKnight;
-                    else cl.kind =  BlackPromotionQueen; /* promotion optional */
-                } else cl.kind = (promoChar == NULLCHAR || promoChar == 'x' || promoChar == '=') ?
-                                            NormalMove : IllegalMove;
-            }
-            if(cl.kind == WhitePromotionQueen || cl.kind == BlackPromotionQueen) {
-                /* for optional promotions append '+' or '=' */
-                if(promoChar == '=') {
-                    *outp++ = '=';
-                    cl.kind = NormalMove;
-                } else *outp++ = '+';
-                *outp = NULLCHAR;
-            } else if(cl.kind == IllegalMove) {
-                /* Illegal move specifies any given promotion */
-                if(promoChar != NULLCHAR && promoChar != 'x') {
-                    *outp++ = '=';
-                    *outp++ = ToUpper(promoChar);
-                    *outp = NULLCHAR;
-                }
+            *outp++ = promoChar; // Don't bother to correct move type, return value is never used!
+        }
+        else if (gameInfo.variant == VariantChuChess && promoChar ||
+                 gameInfo.variant != VariantSuper && promoChar &&
+                 (piece == WhiteLance || piece == BlackLance) ) { // Lance sometimes represents Pawn
+            *outp++ = '=';
+            *outp++ = ToUpper(promoChar);
+        }
+        else if (gameInfo.variant == VariantSChess && promoChar) { // and in S-Chess we have gating
+            ChessSquare victim = board[rt][ft];
+            if(piece == WhiteRook && victim == WhiteKing ||
+               piece == BlackRook && victim == BlackKing) {
+                strncpy(out, "O-O-O", MOVE_LEN);
+                outp = out + 3 + 2*(ft > ff);
             }
+            *outp++ = '/';
+            *outp++ = ToUpper(promoChar);
+            if(out[0] == 'O') *outp++ = ff + AAA;
         }
+       *outp = NULLCHAR;
         return cl.kind;
-       
-      /* [HGM] Always long notation for fairies we don't know */
-      case WhiteFalcon:
-      case BlackFalcon:
-      case WhiteLance:
-      case BlackLance:
-      case WhiteGrasshopper:
-      case BlackGrasshopper:
+
       case EmptySquare:
        /* Moving a nonexistent piece */
        break;
     }
-    
+
     /* Not a legal move, even ignoring check.
-       If there was a piece on the from square, 
+       If there was a piece on the from square,
        use style "Ng1g3" or "Ng1xe8";
        if there was a pawn or nothing (!),
        use style "g1g3" or "g1xe8".  Use "x"
@@ -1594,13 +2505,22 @@ ChessMove CoordsToAlgebraic(board, flags, rf, ff, rt, ft, promoChar, out)
        a piece of the same color.
     */
     outp = out;
+    c = 0;
     if (piece != EmptySquare && piece != WhitePawn && piece != BlackPawn) {
-       *outp++ = ToUpper(PieceToChar(piece));
+       int r, f;
+      for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<=BOARD_RGHT; f++)
+               c += (board[r][f] == piece); // count on-board pieces of given type
+        *outp = PieceToChar(piece);
+        if(*outp == '+') outp++, piece = CHUDEMOTED(piece);
+        *outp++ = ToUpper(PieceToChar(piece));
+        if(*outp = PieceSuffix(piece)) outp++;
     }
+  if(c != 1) { // [HGM] but if there is only one piece of the mentioned type, no from-square, thank you!
     *outp++ = ff + AAA;
     if(rf+ONE <= '9')
        *outp++ = rf + ONE;
     else { *outp++ = (rf+ONE-'0')/10 + '0';*outp++ = (rf+ONE-'0')%10 + '0'; }
+  }
     if (board[rt][ft] != EmptySquare) *outp++ = 'x';
     *outp++ = ft + AAA;
     if(rt+ONE <= '9')
@@ -1630,11 +2550,11 @@ typedef struct {
 int preyStackPointer, chaseStackPointer;
 
 struct {
-char rf, ff, rt, ft;
+unsigned char rf, ff, rt, ft;
 } chaseStack[100];
 
 struct {
-char rank, file;
+unsigned char rank, file;
 } preyStack[100];
 
 
@@ -1646,12 +2566,8 @@ extern void AtacksCallback P((Board board, int flags, ChessMove kind,
                                int rf, int ff, int rt, int ft,
                                VOIDSTAR closure));
 
-void AttacksCallback(board, flags, kind, rf, ff, rt, ft, closure)
-     Board board;
-     int flags;
-     ChessMove kind;
-     int rf, ff, rt, ft;
-     VOIDSTAR closure;
+void
+AttacksCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
 {   // For adding captures that can lead to chase indictment to the chaseStack
     if(board[rt][ft] == EmptySquare) return;                               // non-capture
     if(board[rt][ft] == WhitePawn && rt <  BOARD_HEIGHT/2) return;         // Pawn before river can be chased
@@ -1670,12 +2586,8 @@ extern void ExistingAtacksCallback P((Board board, int flags, ChessMove kind,
                                int rf, int ff, int rt, int ft,
                                VOIDSTAR closure));
 
-void ExistingAttacksCallback(board, flags, kind, rf, ff, rt, ft, closure)
-     Board board;
-     int flags;
-     ChessMove kind;
-     int rf, ff, rt, ft;
-     VOIDSTAR closure;
+void
+ExistingAttacksCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
 {   // for removing pre-exsting captures from the chaseStack, to be left with newly created ones
     int i;
     register ChaseClosure *cl = (ChaseClosure *) closure; //closure tells us the move played in the repeat loop
@@ -1686,8 +2598,8 @@ void ExistingAttacksCallback(board, flags, kind, rf, ff, rt, ft, closure)
     }
     // search move in chaseStack, and delete it if it occurred there (as we know now it is not a new capture)
     for(i=0; i<chaseStackPointer; i++) {
-       if(chaseStack[i].rf == rf && chaseStack[i].ff == ff && 
-          chaseStack[i].rt == rt && chaseStack[i].ft == ft   ) { 
+       if(chaseStack[i].rf == rf && chaseStack[i].ff == ff &&
+          chaseStack[i].rt == rt && chaseStack[i].ft == ft   ) {
            // move found on chaseStack, delete it by overwriting with move popped from top of chaseStack
            chaseStack[i] = chaseStack[--chaseStackPointer];
            break;
@@ -1699,12 +2611,8 @@ extern void ProtectedCallback P((Board board, int flags, ChessMove kind,
                                int rf, int ff, int rt, int ft,
                                VOIDSTAR closure));
 
-void ProtectedCallback(board, flags, kind, rf, ff, rt, ft, closure)
-     Board board;
-     int flags;
-     ChessMove kind;
-     int rf, ff, rt, ft;
-     VOIDSTAR closure;
+void
+ProtectedCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
 {   // for determining if a piece (given through the closure) is protected
     register ChaseClosure *cl = (ChaseClosure *) closure; // closure tells us where to recapture
 
@@ -1715,7 +2623,8 @@ void ProtectedCallback(board, flags, kind, rf, ff, rt, ft, closure)
 
 extern char moveList[MAX_MOVES][MOVE_LEN];
 
-int PerpetualChase(int first, int last)
+int
+PerpetualChase (int first, int last)
 {   // this routine detects if the side to move in the 'first' position is perpetually chasing (when not checking)
     int i, j, k, tail;
     ChaseClosure cl;
@@ -1726,10 +2635,10 @@ int PerpetualChase(int first, int last)
         if(appData.debugMode) fprintf(debugFP, "judge position %i\n", i);
        chaseStackPointer = 0;   // clear stack that is going to hold possible chases
        // determine all captures possible after the move, and put them on chaseStack
-       GenLegal(boards[i+1], PosFlags(i), AttacksCallback, &cl);
-       if(appData.debugMode) { int n; 
-           for(n=0; n<chaseStackPointer; n++) 
-                fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE, 
+       GenLegal(boards[i+1], PosFlags(i), AttacksCallback, &cl, EmptySquare);
+       if(appData.debugMode) { int n;
+           for(n=0; n<chaseStackPointer; n++)
+                fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
                                               chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
             fprintf(debugFP, ": all capts\n");
        }
@@ -1738,10 +2647,12 @@ int PerpetualChase(int first, int last)
        cl.ff = moveList[i][0]-AAA+BOARD_LEFT;
        cl.rt = moveList[i][3]-ONE;
        cl.ft = moveList[i][2]-AAA+BOARD_LEFT;
-       GenLegal(boards[i],   PosFlags(i), ExistingAttacksCallback, &cl);
-       if(appData.debugMode) { int n; 
-           for(n=0; n<chaseStackPointer; n++) 
-                fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE, 
+       CopyBoard(xqCheckers, nullBoard); xqCheckers[EP_STATUS] = 1; // giant kludge to make GenLegal ignore pre-existing checks
+       GenLegal(boards[i],   PosFlags(i), ExistingAttacksCallback, &cl, EmptySquare);
+       xqCheckers[EP_STATUS] = 0; // disable the generation of quasi-legal moves again
+       if(appData.debugMode) { int n;
+           for(n=0; n<chaseStackPointer; n++)
+                fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
                                               chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
             fprintf(debugFP, ": new capts after %c%c%c%c\n", cl.ff+AAA, cl.rf+ONE, cl.ft+AAA, cl.rt+ONE);
        }
@@ -1753,11 +2664,11 @@ int PerpetualChase(int first, int last)
            if(attacker >= (int) BlackPawn) attacker = BLACK_TO_WHITE attacker; // convert to white, as piecee type
            if(victim   >= (int) BlackPawn) victim   = BLACK_TO_WHITE victim;
 
-           if((attacker == WhiteKnight || attacker == WhiteCannon) && victim == WhiteRook) 
+           if((attacker == WhiteKnight || attacker == WhiteCannon) && victim == WhiteRook)
                continue; // C or H attack on R is always chase; leave on chaseStack
 
            if(attacker == victim) {
-                if(LegalityTest(boards[i+1], PosFlags(i+1), chaseStack[j].rt, 
+                if(LegalityTest(boards[i+1], PosFlags(i+1), chaseStack[j].rt,
                    chaseStack[j].ft, chaseStack[j].rf, chaseStack[j].ff, NULLCHAR) == NormalMove) {
                        // we can capture back with equal piece, so this is no chase but a sacrifice
                         chaseStack[j] = chaseStack[--chaseStackPointer]; // delete the capture from the chaseStack
@@ -1767,6 +2678,8 @@ int PerpetualChase(int first, int last)
            }
 
            // the attack is on a lower piece, or on a pinned or blocked equal one
+           CopyBoard(xqCheckers, nullBoard); xqCheckers[EP_STATUS] = 1;
+           CheckTest(boards[i+1], PosFlags(i+1), -1, -1, -1, -1, FALSE); // if we deliver check with our move, the checkers get marked
             // test if the victim is protected by a true protector. First make the capture.
            captured = boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
            boards[i+1][chaseStack[j].rt][chaseStack[j].ft] = boards[i+1][chaseStack[j].rf][chaseStack[j].ff];
@@ -1778,20 +2691,22 @@ int PerpetualChase(int first, int last)
            if(appData.debugMode) {
                fprintf(debugFP, "test if we can recapture %c%c\n", cl.ft+AAA, cl.rt+ONE);
            }
-            GenLegal(boards[i+1], PosFlags(i+1), ProtectedCallback, &cl); // try all moves
+           xqCheckers[EP_STATUS] = 2; // causes GenLegal to ignore the checks we delivered with the move, in real life evaded before we captured
+            GenLegal(boards[i+1], PosFlags(i+1), ProtectedCallback, &cl, EmptySquare); // try all moves
+           xqCheckers[EP_STATUS] = 0; // disable quasi-legal moves again
            // unmake the capture
            boards[i+1][chaseStack[j].rf][chaseStack[j].ff] = boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
             boards[i+1][chaseStack[j].rt][chaseStack[j].ft] = captured;
            // if a recapture was found, piece is protected, and we are not chasing it.
            if(cl.recaptures) { // attacked piece was defended by true protector, no chase
                chaseStack[j] = chaseStack[--chaseStackPointer]; // so delete from chaseStack
-               j--; /* ! */ 
+               j--; /* ! */
            }
        }
        // chaseStack now contains all moves that chased
-       if(appData.debugMode) { int n; 
-           for(n=0; n<chaseStackPointer; n++) 
-                fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE, 
+       if(appData.debugMode) { int n;
+           for(n=0; n<chaseStackPointer; n++)
+                fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
                                               chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
             fprintf(debugFP, ": chases\n");
        }
@@ -1817,8 +2732,8 @@ int PerpetualChase(int first, int last)
            }
        }
         preyStackPointer = tail; // keep bottom part of preyStack, popping pieces unchased on move i.
-       if(appData.debugMode) { int n; 
-            for(n=0; n<preyStackPointer; n++) 
+       if(appData.debugMode) { int n;
+            for(n=0; n<preyStackPointer; n++)
                 fprintf(debugFP, "%c%c ", preyStack[n].file+AAA, preyStack[n].rank+ONE);
             fprintf(debugFP, "always chased upto ply %d\n", i);
        }
@@ -1832,5 +2747,6 @@ int PerpetualChase(int first, int last)
             }
         }
     }
-    return preyStackPointer; // if any piece was left on preyStack, it has been perpetually chased
+    return preyStackPointer ? 256*(preyStack[preyStackPointer].file - BOARD_LEFT + AAA) + (preyStack[preyStackPointer].rank + ONE)
+                               : 0; // if any piece was left on preyStack, it has been perpetually chased,and we return the
 }