-Chu Chess is an intermediate between (Mighty-Lion) Chess and Chu Shogi. -It was designed for over-the-board play with the aid of two Chess sets, some draughts chips, -and an International-Daughts (10x10) board. -Pieces placed on a draughts-chip pedestal would represent 'crowned' pieces, -i.e. pieces that in addition to their normal Chess moves would also be able to move as an orthodox King. -With the exception of the Knight on a pedestal, which would not only get the extra King move, -but the full power of a Chu-Shogi Lion. -(To highlight its importance, it could be put on top of a stack of draughts chips.) -This variant can be played in two versions, differing only in promotion rules, -which can be either Chess-like or Shogi-like. -
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-Initial setup-
-f0, e9: King
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Click on a piece below to see its moves
+Chu Chess is an intermediate between (Mighty-Lion) Chess and + Chu Shogi. It was designed for over-the-board play with the aid + of two Chess sets, some draughts chips, and an + International-Daughts (10x10) board. Pieces placed on a + draughts-chip pedestal would represent 'crowned' pieces, i.e. + pieces that in addition to their normal Chess moves would also be + able to move as an orthodox King. With the exception of the + Knight on a pedestal, which would not only get the extra King + move, but the full power of a Chu-Shogi Lion. (To highlight its + importance, it could be put on top of a stack of draughts chips.) + This variant can be played in two versions, differing only in + promotion rules, which can be either Chess-like or + Shogi-like.
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+ Moves at a Glance- |
+ Click on a piece below to see its moves - |
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Pawn peculiarities-
Castling--A King that has not moved before can move three squares in the direction of a Rook that has not moved before, -in which case that Rook is moved to the square the King skipped over. -This is only allowed if all squares between King and Rook are empty, -when the King is not in check on the square it came from, -and would not be in check on any of the squares it skipped over. - -General rules-
Chess-like or Shogi-like promotion--In the Chess-like version only Pawns promote. -You can choose what piece to promote to, but promotion is mandatory: -you cannot stay a Pawn. -In the Shogi-like version other pieces can also promote, but there is no choice: -pieces promote to their 'crowned' versions, and acquire the moves of a King on top of their own that way. -Pieces that already had all King moves cannot promote. -Thus a Commoner cannot Promote, and a Pawn can only promote to Commoner. -The Knight promotes to Lion, and thus gains unusually much in value. - -The Lion piece--The Lion can make two moves per turn. -That means it can also capture two pieces per turn, -one on the square it moves to (as normal), and one 'en passant' on the transit square. -It can also capture on the transit square, and move on to an empty square ('hit and run'), -or capture and move back to where it came from ('shooting' the piece from a distance, as it were). -Of course it can also capture a single piece in the normal Chess manner. -In that case the transit square is immaterial. - --The Lion can make such double moves as two King steps, -i.e. in all directions, and arbitrarily changing direction between them. -It can also jump over the transit square, i.e. reach the distant two-step destination in a single jump. -Finally it can also just make a step to an adjacent square, refraining from taking a second step. - -Restrictions on Lion capture--There are rules to make Lion trading very difficult, in order to keep the Lions in play. -Basically they specify that two Lions cannot be captured in consecutive half-moves. -When the first capture is Lion x Lion from a distance, -it is forbidden to play it if pseudo-legal (i.e. without taking account of check) recapture of the capturing Lion is possible -with another piece than King. -So even when the Lion is protected only with a pinned piece, the other Lion cannot capture it from a distance, -just like a King could not capture it. - -When a non-Lion captures a Lion, it is just the other way around: -then the 'counterstrike' by a non-Lion against the Lion is forbidden. -One possibility left open is thus when you capture an adjacent Lion. -But then you would in general be foolish to allow recapture, -as you could take the Lion hit-and-run fashion, fleeing to a save square. -An exception to the rule is when a valuable opponent piece (i.e. not a Pawn) forms a 'bridge' between the Lions; -you may then capture that piece in the first leg of the double-move, -and then take the opponent Lion with the second leg. -Then the opponent can recapture, but he will have lost a valuable piece. -In the late end-game, when you have nothing to protect your Lion with other than King, -trading becomes possible. - -XBoard interface issues--This game has to be played with the option Show Target Squares on! -This option will cause marking of the target squares of any piece you select or grab, -by the engine (with legality testing off) or by XBoard (legality testing on). -Moving to a square marked in cyan will be interpreted not as the final destination, -but as the transit square after the first step of a multi-leg move. -XBoard will then highlight the possible destination squares of the second leg from there. -Should you want to end on the cyan square, you click it again, (it will be no longer marked in cyan), -and XBoard will terminate the move after the first leg. -You can also move back to the starting square, to 'shoot' the opponent piece from nearby. - --XBoard will allow both the Chess-like and the Shogi-like promotion; -the engine will have to decide which promotion style it thinks legal. -The default choice in 'sweep-promotions' mode will be deferral for pieces, however, -to facilitate Chess-like play. -To play a Shogi promotion in this mode you should enter it as a click-click move, -but during the click on the promotion square move the mouse pointer down until the promoted piece appears, and only then release the mouse button. -The Pawn will show Queen as default, and a 'dragging click' on the promotion square will cycle through all choices. -In the Shogi version you would have to choose the Commoner that way. -With a promotion popup you would have to press 'No' on piece moves into the zone when you play the Chess-like version, -and press 'Commoner' on Pawn promotions when you play the Shogi-like version. - -Differences with FIDE--The board is 10x10, with a 3-rank-deep promotion zone. -The initial setup leaves an almost empty rank behind the pieces, where you can immediately castle. -You have a Lion, Crowned Rook, Crowned Bishop and two Soldiers as extra pieces. -In the Shogi-like version of the rules, some pieces other than Pawn can also promote. - -Strategy issues--It is not possible to force checkmate on a bare King with just a single Bishop or Knight (in addition to your own King). -Two Knights cannot do that either. - --With a single Commoner you can force checkmate on a bare King. - --Bishops are confined to squares of a single color. -Having Bishops on both colors compensates this weakness, and is worth an extra 0.5 on top of their added value. - --A Queen is upward compatible with all weaker pieces except Knight. -So only promotion to Queen or Knight makes sense, -(except perhaps for rare situations where you might have to avoid stalemate). - -- -- -- + |  |
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| Piece | + +ID | + +value | + +Moves (Betza notation) | + +Remarks | +
| King | + +K | + +- | + +K | + +Can castle with Rook, moving 3 steps towards it | +
| Lion | + +L | + +15 | + +KNAD(cK-aK)(K-bK) | + +Can make two independent King steps per turn (capturing + upto two pieces) | +
| Queen | + +Q | + +9.5 | + +RB or Q | + ++ |
| Crowned Rook | + ++R | + +7 | + +RF | + +aka Dragon Kin | +
| Crowned Bishop | + ++B | + +5.25 | + +BW | + +aka Dragon Horse | +
| Rook | + +R | + +5 | + +R | + ++ |
| Bishop | + +B | + +3.5 | + +B | + +Color-bound | +
| Knight | + +N | + +3 | + +N | + ++ |
| Commoner | + +M | + +3 | + +K | + +aka Man or Soldier | +
| Pawn | + +P | + +1 | + +mfWcfF | + +Promotes to Q, R, B, or N on reaching promotion zone | +
A King that has not moved before can move three squares + in the direction of a Rook that has not moved before, in which + case that Rook is moved to the square the King skipped over. This + is only allowed if all squares between King and Rook are empty, + when the King is not in check on the square it came from, and + would not be in check on any of the squares it skipped over.
+ +In the Chess-like version only Pawns promote. You can choose + what piece to promote to, but promotion is mandatory: you cannot + stay a Pawn. In the Shogi-like version other pieces can also + promote, but there is no choice: pieces promote to their + 'crowned' versions, and acquire the moves of a King on top of + their own that way. Pieces that already had all King moves cannot + promote. Thus a Commoner cannot Promote, and a Pawn can only + promote to Commoner. The Knight promotes to Lion, and thus gains + unusually much in value.
+ +The Lion can make two moves per turn. That means it can also + capture two pieces per turn, one on the square it moves to (as + normal), and one 'en passant' on the transit square. It can also + capture on the transit square, and move on to an empty square + ('hit and run'), or capture and move back to where it came from + ('shooting' the piece from a distance, as it were). Of course it + can also capture a single piece in the normal Chess manner. In + that case the transit square is immaterial.
+ +The Lion can make such double moves as two King steps, i.e. in + all directions, and arbitrarily changing direction between them. + It can also jump over the transit square, i.e. reach the distant + two-step destination in a single jump. Finally it can also just + make a step to an adjacent square, refraining from taking a + second step.
+ +There are rules to make Lion trading very difficult, in order + to keep the Lions in play. Basically they specify that two Lions + cannot be captured in consecutive half-moves. When the first + capture is Lion x Lion from a distance, it is forbidden to play + it if pseudo-legal (i.e. without taking account of check) + recapture of the capturing Lion is possible with another piece + than King. So even when the Lion is protected only with a + pinned piece, the other Lion cannot capture it from a + distance, just like a King could not capture it.
+ +When a non-Lion captures a Lion, it is just the other way + around: then the 'counterstrike' by a non-Lion against the Lion + is forbidden. One possibility left open is thus when you capture + an adjacent Lion. But then you would in general be foolish to + allow recapture, as you could take the Lion hit-and-run fashion, + fleeing to a save square. An exception to the rule is when a + valuable opponent piece (i.e. not a Pawn) forms a 'bridge' + between the Lions; you may then capture that piece in the first + leg of the double-move, and then take the opponent Lion with the + second leg. Then the opponent can recapture, but he will have + lost a valuable piece. In the late end-game, when you have + nothing to protect your Lion with other than King, trading + becomes possible.
+ +This game has to be played with the option Show Target Squares + on! This option will cause marking of the target squares of any + piece you select or grab, by the engine (with legality testing + off) or by XBoard (legality testing on). Moving to a square + marked in cyan will be interpreted not as the final destination, + but as the transit square after the first step of a multi-leg + move. XBoard will then highlight the possible destination squares + of the second leg from there. Should you want to end on the cyan + square, you click it again, (it will be no longer marked in + cyan), and XBoard will terminate the move after the first leg. + You can also move back to the starting square, to 'shoot' the + opponent piece from nearby.
+ +XBoard will allow both the Chess-like and the Shogi-like + promotion; the engine will have to decide which promotion style + it thinks legal. The default choice in 'sweep-promotions' mode + will be deferral for pieces, however, to facilitate Chess-like + play. To play a Shogi promotion in this mode you should enter it + as a click-click move, but during the click on the promotion + square move the mouse pointer down until the promoted piece + appears, and only then release the mouse button. The Pawn will + show Queen as default, and a 'dragging click' on the promotion + square will cycle through all choices. In the Shogi version you + would have to choose the Commoner that way. With a promotion + popup you would have to press 'No' on piece moves into the zone + when you play the Chess-like version, and press 'Commoner' on + Pawn promotions when you play the Shogi-like version.
+ +The board is 10x10, with a 3-rank-deep promotion zone. The + initial setup leaves an almost empty rank behind the pieces, + where you can immediately castle. You have a Lion, Crowned Rook, + Crowned Bishop and two Soldiers as extra pieces. In the + Shogi-like version of the rules, some pieces other than Pawn can + also promote.
+ +It is not possible to force checkmate on a bare King with just + a single Bishop or Knight (in addition to your own King). Two + Knights cannot do that either.
+ +With a single Commoner you can force checkmate on a bare + King.
+ +Bishops are confined to squares of a single color. Having + Bishops on both colors compensates this weakness, and is worth an + extra 0.5 on top of their added value.
+ +A Queen is upward compatible with all weaker pieces except + Knight. So only promotion to Queen or Knight makes sense, (except + perhaps for rare situations where you might have to avoid + stalemate).
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