1 This is gnushogi.info, produced by makeinfo version 4.3 from
4 This file describes how to use GNU shogi, a program which plays
5 Shogi (Japanese chess).
7 Copyright (C) 1999 Michael C. Vanier and the Free Software
10 Permission is granted to make and distribute verbatim copies of this
11 manual provided the copyright notice and this permission notice are
12 preserved on all copies.
14 Permission is granted to copy and distribute modified versions of
15 this manual under the conditions for verbatim copying, provided that
16 the entire resulting derived work is distributed under the terms of a
17 permission notice identical to this one.
19 Permission is granted to copy and distribute translations of this
20 manual into another language, under the above conditions for modified
21 versions, except that this permission notice may be stated in a
22 translation approved by the Free Software Foundation.
25 File: gnushogi.info, Node: Top, Next: (dir), Prev: (dir), Up: (dir)
27 GNU Shogi (Japanese chess)
28 **************************
32 * Introduction:: What is GNU shogi?
33 * License:: The GNU General Public License.
34 * About shogi:: General information, rules, etc.
35 * gnushogi:: How to play GNU shogi (gnushogi).
36 * xshogi:: The X interface to GNU shogi.
37 * References and links:: Where to go for more information.
39 * Bugs:: Where and how to report bugs.
43 File: gnushogi.info, Node: Introduction, Next: License, Prev: Top, Up: Top
48 GNU shogi is a program that plays shogi, the Japanese version of
49 chess, against a human (or computer) opponent. This file describes how
50 to use GNU shogi and also gives background information about the game
53 This file describes GNU shogi version 1.3.2. It was written by me,
54 Mike Vanier, the current maintainer of GNU shogi. My email address is
55 <mvanier@cs.caltech.edu>.
57 GNU shogi is actually two programs:
61 is the text-based program which also contains the game-playing
65 is the X-windows graphical interface to gnushogi.
68 Since xshogi invokes gnushogi, most players will just type "xshogi"
71 Disclaimer: I use the personal pronouns "him", "his" etc. to refer
72 to a shogi player regardless of gender. That's easier than writing
73 "his or her" all over the place. I don't mean to infer that women
74 don't play shogi; in fact shogi is very popular in Japan among women as
78 File: gnushogi.info, Node: License, Next: About shogi, Prev: Introduction, Up: Top
80 GNU GENERAL PUBLIC LICENSE
81 **************************
84 Copyright (C) 1989, 1991 Free Software Foundation, Inc.
85 675 Mass Ave, Cambridge, MA 02139, USA
87 Everyone is permitted to copy and distribute verbatim copies
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141 TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
142 0. This License applies to any program or other work which contains a
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160 1. You may copy and distribute verbatim copies of the Program's
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168 You may charge a fee for the physical act of transferring a copy,
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313 This section is intended to make thoroughly clear what is believed
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369 ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
371 END OF TERMS AND CONDITIONS
373 How to Apply These Terms to Your New Programs
374 =============================================
376 If you develop a new program, and you want it to be of the greatest
377 possible use to the public, the best way to achieve this is to make it
378 free software which everyone can redistribute and change under these
381 To do so, attach the following notices to the program. It is safest
382 to attach them to the start of each source file to most effectively
383 convey the exclusion of warranty; and each file should have at least
384 the "copyright" line and a pointer to where the full notice is found.
386 ONE LINE TO GIVE THE PROGRAM'S NAME AND A BRIEF IDEA OF WHAT IT DOES.
387 Copyright (C) 19YY NAME OF AUTHOR
389 This program is free software; you can redistribute it and/or modify
390 it under the terms of the GNU General Public License as published by
391 the Free Software Foundation; either version 2 of the License, or
392 (at your option) any later version.
394 This program is distributed in the hope that it will be useful,
395 but WITHOUT ANY WARRANTY; without even the implied warranty of
396 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
397 GNU General Public License for more details.
399 You should have received a copy of the GNU General Public License
400 along with this program; if not, write to the Free Software
401 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
403 Also add information on how to contact you by electronic and paper
406 If the program is interactive, make it output a short notice like
407 this when it starts in an interactive mode:
409 Gnomovision version 69, Copyright (C) 19YY NAME OF AUTHOR
410 Gnomovision comes with ABSOLUTELY NO WARRANTY; for details
412 This is free software, and you are welcome to redistribute it
413 under certain conditions; type `show c' for details.
415 The hypothetical commands `show w' and `show c' should show the
416 appropriate parts of the General Public License. Of course, the
417 commands you use may be called something other than `show w' and `show
418 c'; they could even be mouse-clicks or menu items--whatever suits your
421 You should also get your employer (if you work as a programmer) or
422 your school, if any, to sign a "copyright disclaimer" for the program,
423 if necessary. Here is a sample; alter the names:
425 Yoyodyne, Inc., hereby disclaims all copyright interest in the program
426 `Gnomovision' (which makes passes at compilers) written by James Hacker.
428 SIGNATURE OF TY COON, 1 April 1989
429 Ty Coon, President of Vice
431 This General Public License does not permit incorporating your
432 program into proprietary programs. If your program is a subroutine
433 library, you may consider it more useful to permit linking proprietary
434 applications with the library. If this is what you want to do, use the
435 GNU Library General Public License instead of this License.
438 File: gnushogi.info, Node: About shogi, Next: gnushogi, Prev: License, Up: Top
440 About the game of shogi
441 ***********************
443 "Japanese chess cedes nothing in depth or beauty to the European
444 game... it is at least as interesting."
446 -- Alexander Alekhine
447 (quoted in David Pritchard, `The Encyclopedia of Chess Variants')
450 "... shogi [is] by far the most complex form of chess that has ever
451 achieved widespread popularity."
453 -- R. Wayne Schmittberger, `New Rules for Classic Games'
456 Shogi is the version of chess played in Japan. It is strikingly
457 different from standard chess (which I shall refer to henceforth as
458 "international chess") and also to all other regional variants, because
459 captured pieces can re-enter play on the side of the capturer. This
460 has several interesting effects on the play of the game:
463 1. Shogi is much more complex than international chess, at least in
464 terms of the average number of possible moves per turn (estimated
465 at about 35 for chess and at about 80 for shogi).
467 2. There are almost no draws (about 1-2% of all games in professional
470 3. Exchanges complicate the play rather than simplifying it.
472 4. There are no "endgames" in the standard chess sense; all pieces
473 remain in play throughout the game. Games typically end in a race
474 to checkmate the other player before being checkmated oneself.
476 5. Ownership of a piece is not indicated by the color of the piece;
477 instead, pieces are wedge-shaped and point towards the opponent.
478 The name of the piece is inscribed in Kanji characters on the
481 6. Most importantly: it's more fun than other forms of chess :-)
485 Shogi is extremely popular in Japan; it has been estimated that 20
486 million Japanese can play shogi, of which perhaps 1 million are active
487 players. It is even more popular there than the game of go, Japan's
488 other favorite board game. There are a number of professional players
489 who make a considerable amount of money playing in shogi tournaments,
490 and the game receives extensive newpaper and television coverage.
491 Despite this, the game has yet to become popular outside of Japan. Part
492 of this is because the Kanji characters on the pieces scare away some
493 people, but mostly it's due, I think, to lack of exposure to the game
494 and to the difficulty of finding opponents. I hope that GNU shogi will
495 help introduce shogi to a wider audience.
499 * The rules of shogi::
503 * Differences between shogi and chess::
506 File: gnushogi.info, Node: The rules of shogi, Next: Sample game, Prev: About shogi, Up: About shogi
511 Shogi is a two-person abstract strategy board game with full
512 information (i.e. all pieces and moves are visible to both players at
513 all times). It is in the chess family, being descended from the same
514 ancestral game as international chess: the Indian game of Chaturanga.
515 The two players are referred to as "Black" and "White", with Black
516 moving first (unlike in international chess, where White moves first),
517 and with movement alternating between the two players. Note that
518 "Black" and "White" are just names; the pieces are not colored.
519 Instead, they are flat, wedge-shaped pieces which point towards the
520 opponent. The identity of a given piece is indicated by two Japanese
521 Kanji characters on each piece. In fact, only the top character is
522 needed to identify the piece and thus only the top character is used in
523 shogi diagrams. I will use alphabetical equivalents in the diagrams
524 here; to see what the Kanji characters look like, start up xshogi
525 (*note xshogi::) and compare the starting setup there with the starting
526 setup in this file (*note The opening setup::).
528 The object of the game is to capture the opponent's King. The board
529 is a grid of 9x9 uncolored squares, and pieces are placed on the
530 squares. Each player begins with 20 pieces, described in the next
531 section. Capture is by displacement, as in international chess.
535 * The moves of the pieces::
536 * The opening setup::
537 * Promotion of pieces::
542 * Notes for chess players::
545 File: gnushogi.info, Node: The moves of the pieces, Next: The opening setup, Prev: The rules of shogi, Up: The rules of shogi
547 The moves of the pieces
548 -----------------------
550 Each player at the beginning of a shogi game has a total of 20
551 pieces of eight different types. The moves of the shogi pieces can be
552 divided into three classes: "stepping" pieces, that only move one
553 square at a time; "ranging" pieces that move any number of unobstructed
554 squares in a line, and "jumping" pieces that can jump over obstructing
555 pieces to reach their destination squares. Most pieces can also
556 promote to different (usually stronger) pieces under certain
557 circumstances (see the next section). All pieces capture the same way
558 that they move (even pawns). The piece moves and promotions are as
559 follows; each piece name is followed by the standard piece abbreviation:
561 1. The king (K). The king can move one square in any horizontal,
562 vertical, or diagonal direction, just like the king in
563 international chess. The king does not promote.
565 2. The rook (R). The rook can move any number of squares in a
566 horizontal or vertical direction. The rook is the same as the
567 rook in international chess (except that it can promote). A rook
568 promotes to a "dragon king" or "dragon" for short (often just
569 referred to as a "promoted rook"), which can move as a rook or can
570 move one square in any diagonal direction.
572 3. The bishop (B). The bishop can move any number of squares in a
573 diagonal direction. The bishop is the same as the bishop in
574 international chess (except that it can promote). A bishop
575 promotes to a "dragon horse" or "horse" for short (often just
576 referred to as a "promoted bishop"), which can move as a bishop or
577 can move one square in any horizontal or vertical direction.
578 Note: the horse should not be confused with a knight (see below),
579 as they are two completely different pieces.
581 4. The gold general (G). A gold general can move one square in any
582 horizontal or vertical direction, or one square in a forward
583 diagonal direction. Gold generals do not promote.
585 5. The silver general (S). A silver general can move one square in
586 any diagonal direction, or one square straight forward. A silver
587 general promotes to a gold general.
589 6. The knight (N). A knight can move one square straight forward
590 followed by one square to either forward diagonal, jumping over
591 intervening pieces if any. In other words, a knight moves like
592 its international chess counterpart, but forward only. A knight
593 promotes to a gold general. The knight is the only jumping piece,
596 7. The lance (L). A lance can move any number of squares straight
597 forward. A lance promotes to a gold general.
599 8. The pawn (P). A pawn can move one square straight forward. The
600 pawn captures the same way that it moves, in contrast to
601 international chess. There is also no initial two-space move for
602 pawns and no _en-passant_ capture. A pawn promotes to a gold
603 general; a promoted pawn is usually known as a "Tokin".
607 File: gnushogi.info, Node: The opening setup, Next: Promotion of pieces, Prev: The moves of the pieces, Up: The rules of shogi
612 The opening setup for shogi is as follows:
615 +--------------------------------------------+
616 | wL | wN | wS | wG | wK | wG | wS | wN | wL | a
617 +--------------------------------------------+
618 | | wR | | | | | | wB | | b
619 +--------------------------------------------+
620 | wP | wP | wP | wP | wP | wP | wP | wP | wP | c
621 +--------------------------------------------+
622 | | | | | | | | | | d
623 +--------------------------------------------+
624 | | | | | | | | | | e
625 +--------------------------------------------+
626 | | | | | | | | | | f
627 +--------------------------------------------+
628 | bP | bP | bP | bP | bP | bP | bP | bP | bP | g
629 +--------------------------------------------+
630 | | bB | | | | | | bR | | h
631 +--------------------------------------------+
632 | bL | bN | bS | bG | bK | bG | bS | bN | bL | i
633 +--------------------------------------------+
636 Here, "b" stands for "black" and "w" stands for "white", so that,
637 for instance, "bL" means "black lance". The numbers above the files
638 and the letters to the right of the ranks represent the most common
639 notation system used for shogi by westerners (the Japanese also use
640 Arabic numerals for the files but use Japanese numerals for the ranks).
643 File: gnushogi.info, Node: Promotion of pieces, Next: Drops, Prev: The opening setup, Up: The rules of shogi
648 In sharp contrast to international chess, where only pawns can
649 promote to higher-ranked pieces, most of the pieces in shogi can
650 promote. The promoted ranks are discussed in the section on piece
651 moves (*note The moves of the pieces::) but are repeated here for
655 promotes to gold general (called a `tokin' in this case only).
658 promotes to gold general.
661 promotes to gold general.
664 promotes to gold general.
670 promotes to "dragon horse" or just "horse" for short. The horse
671 can move as a bishop or can move one square in any orthogonal
675 promotes to "dragon king" or just "dragon" for short. The dragon
676 can move as a rook or can move one square in any diagonal
683 The three ranks furthest away from each player constitute his/her
684 "promotion zone". A player may, but is not required to, promote a
685 piece after making a move in which the piece begins and/or ends in the
686 promotion zone. Thus you can promote a piece when moving the piece into
687 the promotion zone, out of the promotion zone, or entirely within the
688 promotion zone. Promotion is mandatory in these cases:
691 1. You must promote a pawn or a lance after moving it to the last
694 2. You must promote a knight after moving it to either of the last
699 These forced promotions ensure that a piece cannot be moved to a
700 square from which it would have no further move.
702 Pieces "dropped" onto the board (*note Drops::) always drop in the
703 unpromoted state, even if they drop into the promotion zone.
706 File: gnushogi.info, Node: Drops, Next: Winning the game, Prev: Promotion of pieces, Up: The rules of shogi
711 When a player captures a piece, that piece is not removed from play.
712 Instead, it becomes the property of the capturer and can re-enter play
713 by being placed on (almost) any vacant square during the player's move.
714 This is known as a "drop" and counts as a full move (in other words,
715 you can either move a piece on the board or drop a piece onto the board
716 during your move, but not both). All pieces drop in the unpromoted
717 state. Pieces may be legally dropped in their promotion zone, but they
718 do not promote on that turn.
720 There are several restrictions on drops:
722 1. A pawn may not be dropped onto a file if there is already an
723 unpromoted pawn belonging to the same player on that file. It is
724 legal to drop a pawn on a file which contains a _promoted_ pawn
725 belonging to the same player, however.
727 2. A pawn may not be dropped to give immediate checkmate on the move.
728 A pawn is, however, permitted to be moved on the board to give
729 immediate checkmate. This is a curious rule, and if anyone knows
730 the reason for it I would appreciate it if they would contact me
731 and explain it to me :-)
733 3. A pawn or piece may not be dropped onto a square from which they
734 would have no legal move. This means that pawns and lances may
735 not be dropped onto the last rank, and the knight may not be
736 dropped onto the last or second-to-last rank.
739 It is entirely permissible (and often advisable) to drop a piece or
740 pawn between one's King and an attacking ranging piece. For this
741 reason, the final checkmating move is nearly always an attack on the
742 King from an adjacent square (except for an attack by a Knight).
744 Captured pieces are said to be pieces "in hand".
746 The drop is the primary distinguishing feature of Japanese chess,
747 shared with no other popular chess-type game. It gives shogi a very
748 aggressive quality, and dramatically increases the number of possible
749 moves once a few pieces have been captured. Another interesting
750 feature of shogi is that exchanges complicate play rather than
751 simplifying it (as in international chess), because of the drop rule.
754 File: gnushogi.info, Node: Winning the game, Next: Draws, Prev: Drops, Up: The rules of shogi
759 A game of shogi is won by capturing the opponent's king. In general,
760 this is done by checkmating the king: attacking the king in such a way
761 that the king cannot be defended no matter what the defending player
762 moves. Note, though, that there is no rule that requires a player to
763 defend a king which is being attacked. However, if he does not defend
764 his king, the opponent is entirely free to capture it on the next move,
765 thus winning the game. As in international chess, in practice most
766 games end by resignation when one player realizes that he cannot escape
770 File: gnushogi.info, Node: Draws, Next: Handicaps, Prev: Winning the game, Up: The rules of shogi
775 There are very few draws in shogi; only about 1-2% of professional
776 games end in a draw. One reason for this is that material can never be
777 depleted as in chess, because captured pieces are constantly re-entering
778 play as a consequence of the drop rule. In fact, most of the ways a
779 game can be drawn in chess are not allowed in shogi:
782 * Draws cannot be offered.
784 * There is no fifty-move rule.
786 * A stalemate counts as a win for the stalemater. Stated otherwise:
787 if you can't move, you lose.
789 * Perpetual check is illegal (see below).
793 There are only two legal ways in which a draw can occur:
796 1. A position (including the pieces in hand) occurs 4 times with the
797 same player to move (called "Sennichite"). However, if this is
798 caused by consecutive checks (direct attacks on the King,
799 threatening to capture it on the next move) by one side, the
800 player giving these checks loses the game. In other words,
801 perpetual check results in a loss for the attacker who recreates
802 the same position the 4th time.
804 2. Both players have moved their King into the the promotion zone (or
805 they cannot be prevented from doing so) and the Kings cannot be
806 checkmated. A King who has entered the promotion zone is known as
807 an "entering King"; due to the forward orientation of most shogi
808 pieces, it is very hard to mate such a King. In that case the
809 players may decide to count their pieces as follows: the King does
810 not count, the Rook and Bishop count as 5 points, and all other
811 pieces as one point. Promotion is disregarded. If both players
812 have at least 24 points the game is a draw (called "Jishogi"). If
813 a player has less, he loses the game.
815 Of course, a player can refuse to count pieces when he still has
816 mating chances or chances to gain material which would affect the
817 outcome of the counting. There is no strict rule about what to do
818 if this is not the case, but nonetheless a player refuses to count
819 up (e.g. because he does not have enough points for a draw). It
820 has been generally accepted that in such a case the game ends and
821 the pieces are counted after one player has managed to get all his
822 pieces protected in the promotion zone.
827 File: gnushogi.info, Node: Handicaps, Next: Notes for chess players, Prev: Draws, Up: The rules of shogi
832 Unlike international chess, shogi has a well-established handicap
833 system which is used when players of different strengths play against
834 each other. Handicaps range from small to huge, which makes it
835 possible for weak players to play against even very strong players and
836 have an even chance of winning.
838 Shogi players are ranked as follows: the weakest rank is around 15
839 "kyu", which represents a beginner. 14 kyu is higher than 15 kyu, 13
840 kyu is higher still, and so on until you get to 1 kyu. The next highest
841 rank is 1 "dan", followed by 2 dan, 3 dan and so forth. The highest
842 amateur rank is 6 dan; professionals go up to 9 dan. However,
843 professional ranks are not the same as amateur ranks; a professional 1
844 dan is _much_ stronger than an amateur 1 dan. This system is similar
845 to that used by go players (and also other Japanese sports such as
848 A handicap consists of the stronger player playing White and removing
849 one or more pieces from his side of the board at the start of the game.
850 These pieces are permanently removed from play; they are not in hand.
852 The following is a list of the accepted handicaps, from weakest to
853 strongest. The degree of the handicap, represented by the position in
854 the list, represents the difference in rank between the two players for
855 which the handicap is appropriate. These rules are taken from the books
856 "Shogi for Beginners" by John Fairbairn and "The Art of Shogi" by Tony
857 Hoskings (*note References and links::) and, I believe, represent
858 current Japanese practice.
861 1. The stronger player removes his left lance (on 1a).
863 2. The players play a two-game match; in the first game the stronger
864 player removes his left lance (on 1a), while in the second game he
867 3. The stronger player removes his bishop.
869 4. The stronger player removes his rook.
871 5. The stronger player removes his rook and left lance.
873 6. The players play a two-game match; in the first game the stronger
874 player removes his rook and left lance (on 1a), while in the
875 second game he removes his rook and bishop.
877 7. The stronger player removes his rook and bishop. This is usually
878 called a "two-piece" handicap.
880 8. The stronger player removes his rook, bishop, and both lances.
881 This is called a "four-piece" handicap.
883 9. The stronger player removes his rook, bishop, both lances, and both
884 knights. This is called a "six-piece" handicap.
886 10. The stronger player removes his rook, bishop, both lances, both
887 knights, and both silvers. This is called an "eight-piece"
892 Another advantage of playing handicap games is that the handicaps
893 alter the optimal strategy for both players. For instance, handicaps
894 all have their own opening lines which may bear little or no
895 resemblance to those used in non-handicap shogi. This means that when
896 learning handicap shogi, you are essentially learning completely new
897 games which use the same equipment!
899 The reader may wonder how on earth a player giving an eight-piece
900 handicap, say, could possibly hope to win. Don't forget, though, that
901 in shogi the opponent's pieces can be captured and then become part of
902 one's own army. Thus, if the opponent plays badly enough, the number of
903 pieces will soon even out.
906 File: gnushogi.info, Node: Notes for chess players, Prev: Handicaps, Up: The rules of shogi
908 Notes for chess players
909 -----------------------
911 Here are a few miscellaneous things that may confuse chess players.
912 Some of these have been mentioned elsewhere, but they bear repeating.
915 1. There is no queen.
917 2. Pawns capture the same way they move. There is no initial
918 two-space pawn move and no _en-passant_ move.
920 3. There is no special castling move. There _are_ a large number of
921 possible defensive formations referred to as "castles" (*note
922 Sample game::) but there is no need for special moves to create
925 4. A given piece can only promote to _one_ other kind of piece.
930 File: gnushogi.info, Node: Sample game, Next: Mating problems, Prev: The rules of shogi, Up: About shogi
935 This game was annotated by Pieter Stouten (*note References and
936 links::). I have made some minor corrections. Note that captures are
937 denoted by the "x" symbol e.g. Rx3f and drops are denoted by the "*"
938 symbol e.g. R*3f. Check is indicated by a "+" after the move, e.g.
939 R3f+. I recommend you use gnushogi/xshogi to play along with this
940 game. In xshogi simply hit the "Force Moves" button after starting up,
941 while in gnushogi enter the word "force" at the prompt. This will
942 allow you to enter moves for both sides.
944 Note also that the move numbering system used here is the chess-type
945 system where one move means one move by each player. The Japanese count
946 one move made by each player as two moves.
948 --------------------------------------------------------------------------
950 Below you will find (the English translation of) an annotated game
951 which was published in the Dutch Shogi magazine "81" and in the Dutch
952 beginners booklet. It has proven to be a very useful game to explain
953 some basic principles of Shogi. Also, it is a rather straightforward
954 game compared to professional games where in most cases very diffuse
955 middle game fights take place.
957 Pieter Stouten, 14th May 1990.
959 --------------------------------------------------------------------------
961 Black: Michael Trent (1-dan). White: David Murphy (2-dan).
963 1. P2f P3d 2. P2e B3c
964 [ This move is necessary, as otherwise white can exchange pawns: 3. P2d
965 Px2d 4. Rx2d. He would thus get a pawn in hand and open up his rook
969 [ White closes the bishop diagonal again. He plans to play ranging rook
970 (the rook goes to 5b, 4b, 3 or 2b; a defensive strategy) and in that
971 case he'd better avoid an exchange of bishops. One of the reasons is
972 that he will have problems developing his pieces without leaving holes
975 4. S4h R3b 5. P3f S4b 6. K6h K6b
976 [ In general the rook plays an important role in the attacks. It is
977 wise to move the king away from the area where the initial fights will
978 be and both players act according to the Shogi proverb "keep the rook
981 7. K7h K7b 8. P5f P5d 9. G4i-5h G4a-5b
982 [ Both players use their second gold general to build their castle. ]
985 [ In itself this move is not bad. However, it will become clear that
986 black plans a quick attack and in that case it is wiser to omit this
989 10... S5c 11. P1f P1d
990 [ The advance of the edge pawns must be timed very well. The remark at
991 black's tenth move applies here too: this move is good if black wants to
992 play a slow game, because it eliminates a future B1e. ]
994 12. P4f K8b 13. N3g S7b
995 [ Black develops his knight in order to start an attack over the second,
996 third and fourth files. White strengthens his king's position and
997 awaits the attack. He aims at a counterattack as soon as black has
998 broken through into the white camp. Probably white's breakthrough will
999 take place later, but he has good compensation in the form of a stronger
1000 castle. This theme occurs very often in static rook versus ranging rook
1004 [ Black starts his attack and white puts up a very passive defence. His
1005 rook has a hard task now to penetrate the black position. Moreover, he
1006 blocks his own bishop. It seems much better to start a counterattack
1007 with 14... P3e, later to be followed by B2b, B5a or Bx4d in order to use
1008 his rook more actively. ]
1010 15. Px4d Sx4d 16. P*4e S5c
1011 [ 16... Sx4e is more active. A silver general is normally more valuable
1012 than a knight, but white gets two pawns in hand and black none, while
1013 the knight might come in handy for white too. ]
1015 17. Bx3c+ Nx3c 18. P2d Px2d
1016 [ Black threatens to break through and white has to consider taking the
1017 pawn on 2d or starting a counterattack with Nx4e. If he chooses the
1018 latter, black can play Px2c+ followed by +P3c. The disadvantage is the
1019 black "tokin" (=promoted pawn) that white will get in his camp; the
1020 advantage is that it will cost black two more moves to promote his rook.
1021 Because white did not trust that the result after engaging in a
1022 "semeai" (=mutual attack) with 18...Nx4e would give a positive result,
1023 he captured the pawn on 2d. Making the right decision in moments like
1024 this often makes the difference between a win and a loss: miss one
1025 attacking chance and you will be forced to defend the whole game until
1026 the unavoidable defeat; on the other hand, an unsound attack can destroy
1027 all "aji" (=potential, meaning possibilities, threats) without getting
1028 anything in return. ]
1030 19. Rx2d Nx4e 20. Nx4e Rx4e 21. R2a+ P*4g
1031 [ Now it becomes clear why black's 10. S6h was not good. Had this move
1032 been omitted, then white would not have had the time to play 13... S7b
1033 and after R2a+ the gold on 6a would hang. Thus black would have kept
1034 "sente" (=initiative). Instead of 21... P*4g, B*6d is a very good
1035 move, because after 22. P*2h black does not have a pawn in hand anymore
1036 and he is being threatened with the annoying 22... N*4f 23. G5g N3h+
1037 24. S4g +N4h also. Black can also counter 21... B*6d with 22. N*3g.
1038 White would then reply with 22... R4b 23. B*3c P*4g 24. Bx4b+ Sx4b. The
1039 white rook has played its role and instead of spending moves on saving
1040 it white starts to scatter black's defences by successive pawn drops on
1041 the fourth file: 25. Gx4g P*4f 26. G5g N*6e 27. G5h P4g+ 28. Gx4g P*4f.
1042 This analysis was provided by Kato Hifumi, 9-dan professional (the
1043 highest regular grade). Destroying the coherence of the enemy pieces
1044 (their shape) by dropping pawns is one of the most important Shogi
1045 techniques. With the actual move 21... P*4g white missed a good
1048 22. Sx4g P*4f 23. B*3g Px4g+ 24. +Rx6a +Px3g
1049 [ 23. B*3g seems pointless, but a closer look reveals that it is
1050 actually quite mean. On move 24 white cannot capture black's "Ryu"
1051 (=dragon =promoted rook) with his silver: 24... Sx6a 25. N*7d K7b 26.
1052 G*8b mate. By attacking the front of the white castle and threatening
1053 to mate him there, black has the chance to break down the white
1054 defences from the side. ]
1057 [ Here 25... B*4d would be much better, because it is defensive and
1058 attacking at the same time. After e.g. 26. G*4c Bx9i+ 27. Gx5c black
1059 threatens 28. +Rx7b Kx7b 29. S*6a K8b 30. S*7a Kx7a 31. G*7b mate.
1060 White is one move quicker, however. He has the following beautiful
1061 "tsume" (mating sequence where every move is check): 27... N*8f 28. Px8f
1062 S*8g 29. Kx8g B*9h 30. K7h Bx8i+ 31. K8g +B8i-8h 32. K9f L*9e mate.
1063 This illustrates the sharpness of Shogi: one move can make the
1064 difference between winning and losing. ]
1067 [ This move eliminates white's last chances. 26... R4b 27. +Rx4b Sx4b
1068 28. R*4a seems annoying, but after 28... B*3c 29. S7g B*3b white wins
1069 the rook and with his "tokin" on 3g there still is some hope. ]
1072 [ White cannot defend anymore, so he starts a desperate attack. Black
1073 does not lose the right track, however. ]
1075 28. Nx5c+ +Px5h 29. +Nx6b +Px6h 30. Gx6h N*8f 31. Px8f B*6i 32.
1076 Gx6i R4h+ 33. N*6h +Rx6h 34. Gx6h S*8g 35. Kx8g N*9e 36. K7h
1078 [ White resigns here, because after 36... B*8g 27. K7g his attack has