1 This is gnushogi.info, produced by Makeinfo version 3.12h 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. It was written by me,
54 Mike Vanier, the current maintainer of GNU shogi. My email address is
55 <mvanier@bbb.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 **************************
85 Copyright (C) 1989, 1991 Free Software Foundation, Inc.
86 675 Mass Ave, Cambridge, MA 02139, USA
88 Everyone is permitted to copy and distribute verbatim copies
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142 TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
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373 END OF TERMS AND CONDITIONS
375 How to Apply These Terms to Your New Programs
376 =============================================
378 If you develop a new program, and you want it to be of the greatest
379 possible use to the public, the best way to achieve this is to make it
380 free software which everyone can redistribute and change under these
383 To do so, attach the following notices to the program. It is safest
384 to attach them to the start of each source file to most effectively
385 convey the exclusion of warranty; and each file should have at least
386 the "copyright" line and a pointer to where the full notice is found.
388 ONE LINE TO GIVE THE PROGRAM'S NAME AND A BRIEF IDEA OF WHAT IT DOES.
389 Copyright (C) 19YY NAME OF AUTHOR
391 This program is free software; you can redistribute it and/or modify
392 it under the terms of the GNU General Public License as published by
393 the Free Software Foundation; either version 2 of the License, or
394 (at your option) any later version.
396 This program is distributed in the hope that it will be useful,
397 but WITHOUT ANY WARRANTY; without even the implied warranty of
398 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
399 GNU General Public License for more details.
401 You should have received a copy of the GNU General Public License
402 along with this program; if not, write to the Free Software
403 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
405 Also add information on how to contact you by electronic and paper
408 If the program is interactive, make it output a short notice like
409 this when it starts in an interactive mode:
411 Gnomovision version 69, Copyright (C) 19YY NAME OF AUTHOR
412 Gnomovision comes with ABSOLUTELY NO WARRANTY; for details
414 This is free software, and you are welcome to redistribute it
415 under certain conditions; type `show c' for details.
417 The hypothetical commands `show w' and `show c' should show the
418 appropriate parts of the General Public License. Of course, the
419 commands you use may be called something other than `show w' and `show
420 c'; they could even be mouse-clicks or menu items--whatever suits your
423 You should also get your employer (if you work as a programmer) or
424 your school, if any, to sign a "copyright disclaimer" for the program,
425 if necessary. Here is a sample; alter the names:
427 Yoyodyne, Inc., hereby disclaims all copyright interest in the program
428 `Gnomovision' (which makes passes at compilers) written by James Hacker.
430 SIGNATURE OF TY COON, 1 April 1989
431 Ty Coon, President of Vice
433 This General Public License does not permit incorporating your
434 program into proprietary programs. If your program is a subroutine
435 library, you may consider it more useful to permit linking proprietary
436 applications with the library. If this is what you want to do, use the
437 GNU Library General Public License instead of this License.
440 File: gnushogi.info, Node: About shogi, Next: gnushogi, Prev: License, Up: Top
442 About the game of shogi
443 ***********************
445 "Japanese chess cedes nothing in depth or beauty to the European
446 game... it is at least as interesting."
448 -- Alexander Alekhine
449 (quoted in David Pritchard, `The Encyclopedia of Chess Variants')
452 "... shogi [is] by far the most complex form of chess that has ever
453 achieved widespread popularity."
455 -- R. Wayne Schmittberger, `New Rules for Classic Games'
458 Shogi is the version of chess played in Japan. It is strikingly
459 different from standard chess (which I shall refer to henceforth as
460 "international chess") and also to all other regional variants, because
461 captured pieces can re-enter play on the side of the capturer. This
462 has several interesting effects on the play of the game:
465 1. Shogi is much more complex than international chess, at least in
466 terms of the average number of possible moves per turn (estimated
467 at about 35 for chess and at about 80 for shogi).
469 2. There are almost no draws (about 1-2% of all games in professional
472 3. Exchanges complicate the play rather than simplifying it.
474 4. There are no "endgames" in the standard chess sense; all pieces
475 remain in play throughout the game. Games typically end in a race
476 to checkmate the other player before being checkmated oneself.
478 5. Ownership of a piece is not indicated by the color of the piece;
479 instead, pieces are wedge-shaped and point towards the opponent.
480 The name of the piece is inscribed in Kanji characters on the
483 6. Most importantly: it's more fun than other forms of chess :-)
487 Shogi is extremely popular in Japan; it has been estimated that 20
488 million Japanese can play shogi, of which perhaps 1 million are active
489 players. It is even more popular there than the game of go, Japan's
490 other favorite board game. There are a number of professional players
491 who make a considerable amount of money playing in shogi tournaments,
492 and the game receives extensive newpaper and television coverage.
493 Despite this, the game has yet to become popular outside of Japan. Part
494 of this is because the Kanji characters on the pieces scare away some
495 people, but mostly it's due, I think, to lack of exposure to the game
496 and to the difficulty of finding opponents. I hope that GNU shogi will
497 help introduce shogi to a wider audience.
501 * The rules of shogi::
505 * Differences between shogi and chess::
508 File: gnushogi.info, Node: The rules of shogi, Next: Sample game, Prev: About shogi, Up: About shogi
513 Shogi is a two-person abstract strategy board game with full
514 information (i.e. all pieces and moves are visible to both players at
515 all times). It is in the chess family, being descended from the same
516 ancestral game as international chess: the Indian game of Chaturanga.
517 The two players are referred to as "Black" and "White", with Black
518 moving first (unlike in international chess, where White moves first),
519 and with movement alternating between the two players. Note that
520 "Black" and "White" are just names; the pieces are not colored.
521 Instead, they are flat, wedge-shaped pieces which point towards the
522 opponent. The identity of a given piece is indicated by two Japanese
523 Kanji characters on each piece. In fact, only the top character is
524 needed to identify the piece and thus only the top character is used in
525 shogi diagrams. I will use alphabetical equivalents in the diagrams
526 here; to see what the Kanji characters look like, start up xshogi
527 (*note xshogi::.) and compare the starting setup there with the
528 starting setup in this file (*note The opening setup::.).
530 The object of the game is to capture the opponent's King. The board
531 is a grid of 9x9 uncolored squares, and pieces are placed on the
532 squares. Each player begins with 20 pieces, described in the next
533 section. Capture is by displacement, as in international chess.
537 * The moves of the pieces::
538 * The opening setup::
539 * Promotion of pieces::
544 * Notes for chess players::
547 File: gnushogi.info, Node: The moves of the pieces, Next: The opening setup, Prev: The rules of shogi, Up: The rules of shogi
549 The moves of the pieces
550 -----------------------
552 Each player at the beginning of a shogi game has a total of 20
553 pieces of eight different types. The moves of the shogi pieces can be
554 divided into three classes: "stepping" pieces, that only move one
555 square at a time; "ranging" pieces that move any number of unobstructed
556 squares in a line, and "jumping" pieces that can jump over obstructing
557 pieces to reach their destination squares. Most pieces can also
558 promote to different (usually stronger) pieces under certain
559 circumstances (see the next section). All pieces capture the same way
560 that they move (even pawns). The piece moves and promotions are as
561 follows; each piece name is followed by the standard piece abbreviation:
563 1. The king (K). The king can move one square in any horizontal,
564 vertical, or diagonal direction, just like the king in
565 international chess. The king does not promote.
567 2. The rook (R). The rook can move any number of squares in a
568 horizontal or vertical direction. The rook is the same as the
569 rook in international chess (except that it can promote). A rook
570 promotes to a "dragon king" or "dragon" for short (often just
571 referred to as a "promoted rook"), which can move as a rook or can
572 move one square in any diagonal direction.
574 3. The bishop (B). The bishop can move any number of squares in a
575 diagonal direction. The bishop is the same as the bishop in
576 international chess (except that it can promote). A bishop
577 promotes to a "dragon horse" or "horse" for short (often just
578 referred to as a "promoted bishop"), which can move as a bishop or
579 can move one square in any horizontal or vertical direction.
580 Note: the horse should not be confused with a knight (see below),
581 as they are two completely different pieces.
583 4. The gold general (G). A gold general can move one square in any
584 horizontal or vertical direction, or one square in a forward
585 diagonal direction. Gold generals do not promote.
587 5. The silver general (S). A silver general can move one square in
588 any diagonal direction, or one square straight forward. A silver
589 general promotes to a gold general.
591 6. The knight (N). A knight can move one square straight forward
592 followed by one square to either forward diagonal, jumping over
593 intervening pieces if any. In other words, a knight moves like
594 its international chess counterpart, but forward only. A knight
595 promotes to a gold general. The knight is the only jumping piece,
598 7. The lance (L). A lance can move any number of squares straight
599 forward. A lance promotes to a gold general.
601 8. The pawn (P). A pawn can move one square straight forward. The
602 pawn captures the same way that it moves, in contrast to
603 international chess. There is also no initial two-space move for
604 pawns and no _en-passant_ capture. A pawn promotes to a gold
605 general; a promoted pawn is usually known as a "Tokin".
609 File: gnushogi.info, Node: The opening setup, Next: Promotion of pieces, Prev: The moves of the pieces, Up: The rules of shogi
614 The opening setup for shogi is as follows:
617 +--------------------------------------------+
618 | wL | wN | wS | wG | wK | wG | wS | wN | wL | a
619 +--------------------------------------------+
620 | | wR | | | | | | wB | | b
621 +--------------------------------------------+
622 | wP | wP | wP | wP | wP | wP | wP | wP | wP | c
623 +--------------------------------------------+
624 | | | | | | | | | | d
625 +--------------------------------------------+
626 | | | | | | | | | | e
627 +--------------------------------------------+
628 | | | | | | | | | | f
629 +--------------------------------------------+
630 | bP | bP | bP | bP | bP | bP | bP | bP | bP | g
631 +--------------------------------------------+
632 | | bB | | | | | | bR | | h
633 +--------------------------------------------+
634 | bL | bN | bS | bG | bK | bG | bS | bN | bL | i
635 +--------------------------------------------+
638 Here, "b" stands for "black" and "w" stands for "white", so that,
639 for instance, "bL" means "black lance". The numbers above the files
640 and the letters to the right of the ranks represent the most common
641 notation system used for shogi by westerners (the Japanese also use
642 Arabic numerals for the files but use Japanese numerals for the ranks).
645 File: gnushogi.info, Node: Promotion of pieces, Next: Drops, Prev: The opening setup, Up: The rules of shogi
650 In sharp contrast to international chess, where only pawns can
651 promote to higher-ranked pieces, most of the pieces in shogi can
652 promote. The promoted ranks are discussed in the section on piece
653 moves (*note The moves of the pieces::.) but are repeated here for
657 promotes to gold general (called a `tokin' in this case only).
660 promotes to gold general.
663 promotes to gold general.
666 promotes to gold general.
672 promotes to "dragon horse" or just "horse" for short. The horse
673 can move as a bishop or can move one square in any orthogonal
677 promotes to "dragon king" or just "dragon" for short. The dragon
678 can move as a rook or can move one square in any diagonal
685 The three ranks furthest away from each player constitute his/her
686 "promotion zone". A player may, but is not required to, promote a
687 piece after making a move in which the piece begins and/or ends in the
688 promotion zone. Thus you can promote a piece when moving the piece into
689 the promotion zone, out of the promotion zone, or entirely within the
690 promotion zone. Promotion is mandatory in these cases:
693 1. You must promote a pawn or a lance after moving it to the last
696 2. You must promote a knight after moving it to either of the last
701 These forced promotions ensure that a piece cannot be moved to a
702 square from which it would have no further move.
704 Pieces "dropped" onto the board (*note Drops::.) always drop in the
705 unpromoted state, even if they drop into the promotion zone.
708 File: gnushogi.info, Node: Drops, Next: Winning the game, Prev: Promotion of pieces, Up: The rules of shogi
713 When a player captures a piece, that piece is not removed from play.
714 Instead, it becomes the property of the capturer and can re-enter play
715 by being placed on (almost) any vacant square during the player's move.
716 This is known as a "drop" and counts as a full move (in other words,
717 you can either move a piece on the board or drop a piece onto the board
718 during your move, but not both). All pieces drop in the unpromoted
719 state. Pieces may be legally dropped in their promotion zone, but they
720 do not promote on that turn.
722 There are several restrictions on drops:
724 1. A pawn may not be dropped onto a file if there is already an
725 unpromoted pawn belonging to the same player on that file. It is
726 legal to drop a pawn on a file which contains a _promoted_ pawn
727 belonging to the same player, however.
729 2. A pawn may not be dropped to give immediate checkmate on the move.
730 A pawn is, however, permitted to be moved on the board to give
731 immediate checkmate. This is a curious rule, and if anyone knows
732 the reason for it I would appreciate it if they would contact me
733 and explain it to me :-)
735 3. A pawn or piece may not be dropped onto a square from which they
736 would have no legal move. This means that pawns and lances may
737 not be dropped onto the last rank, and the knight may not be
738 dropped onto the last or second-to-last rank.
741 It is entirely permissible (and often advisable) to drop a piece or
742 pawn between one's King and an attacking ranging piece. For this
743 reason, the final checkmating move is nearly always an attack on the
744 King from an adjacent square (except for an attack by a Knight).
746 Captured pieces are said to be pieces "in hand".
748 The drop is the primary distinguishing feature of Japanese chess,
749 shared with no other popular chess-type game. It gives shogi a very
750 aggressive quality, and dramatically increases the number of possible
751 moves once a few pieces have been captured. Another interesting
752 feature of shogi is that exchanges complicate play rather than
753 simplifying it (as in international chess), because of the drop rule.
756 File: gnushogi.info, Node: Winning the game, Next: Draws, Prev: Drops, Up: The rules of shogi
761 A game of shogi is won by capturing the opponent's king. In general,
762 this is done by checkmating the king: attacking the king in such a way
763 that the king cannot be defended no matter what the defending player
764 moves. Note, though, that there is no rule that requires a player to
765 defend a king which is being attacked. However, if he does not defend
766 his king, the opponent is entirely free to capture it on the next move,
767 thus winning the game. As in international chess, in practice most
768 games end by resignation when one player realizes that he cannot escape
772 File: gnushogi.info, Node: Draws, Next: Handicaps, Prev: Winning the game, Up: The rules of shogi
777 There are very few draws in shogi; only about 1-2% of professional
778 games end in a draw. One reason for this is that material can never be
779 depleted as in chess, because captured pieces are constantly re-entering
780 play as a consequence of the drop rule. In fact, most of the ways a
781 game can be drawn in chess are not allowed in shogi:
784 * Draws cannot be offered.
786 * There is no fifty-move rule.
788 * A stalemate counts as a win for the stalemater. Stated otherwise:
789 if you can't move, you lose.
791 * Perpetual check is illegal (see below).
795 There are only two legal ways in which a draw can occur:
798 1. A position (including the pieces in hand) occurs 4 times with the
799 same player to move (called "Sennichite"). However, if this is
800 caused by consecutive checks (direct attacks on the King,
801 threatening to capture it on the next move) by one side, the
802 player giving these checks loses the game. In other words,
803 perpetual check results in a loss for the attacker who recreates
804 the same position the 4th time.
806 2. Both players have moved their King into the the promotion zone (or
807 they cannot be prevented from doing so) and the Kings cannot be
808 checkmated. A King who has entered the promotion zone is known as
809 an "entering King"; due to the forward orientation of most shogi
810 pieces, it is very hard to mate such a King. In that case the
811 players may decide to count their pieces as follows: the King does
812 not count, the Rook and Bishop count as 5 points, and all other
813 pieces as one point. Promotion is disregarded. If both players
814 have at least 24 points the game is a draw (called "Jishogi"). If
815 a player has less, he loses the game.
817 Of course, a player can refuse to count pieces when he still has
818 mating chances or chances to gain material which would affect the
819 outcome of the counting. There is no strict rule about what to do
820 if this is not the case, but nonetheless a player refuses to count
821 up (e.g. because he does not have enough points for a draw). It
822 has been generally accepted that in such a case the game ends and
823 the pieces are counted after one player has managed to get all his
824 pieces protected in the promotion zone.
829 File: gnushogi.info, Node: Handicaps, Next: Notes for chess players, Prev: Draws, Up: The rules of shogi
834 Unlike international chess, shogi has a well-established handicap
835 system which is used when players of different strengths play against
836 each other. Handicaps range from small to huge, which makes it
837 possible for weak players to play against even very strong players and
838 have an even chance of winning.
840 Shogi players are ranked as follows: the weakest rank is around 15
841 "kyu", which represents a beginner. 14 kyu is higher than 15 kyu, 13
842 kyu is higher still, and so on until you get to 1 kyu. The next highest
843 rank is 1 "dan", followed by 2 dan, 3 dan and so forth. The highest
844 amateur rank is 6 dan; professionals go up to 9 dan. However,
845 professional ranks are not the same as amateur ranks; a professional 1
846 dan is _much_ stronger than an amateur 1 dan. This system is similar
847 to that used by go players (and also other Japanese sports such as
850 A handicap consists of the stronger player playing White and removing
851 one or more pieces from his side of the board at the start of the game.
852 These pieces are permanently removed from play; they are not in hand.
854 The following is a list of the accepted handicaps, from weakest to
855 strongest. The degree of the handicap, represented by the position in
856 the list, represents the difference in rank between the two players for
857 which the handicap is appropriate. These rules are taken from the books
858 "Shogi for Beginners" by John Fairbairn and "The Art of Shogi" by Tony
859 Hoskings (*note References and links::.) and, I believe, represent
860 current Japanese practice.
863 1. The stronger player removes his left lance (on 1a).
865 2. The players play a two-game match; in the first game the stronger
866 player removes his left lance (on 1a), while in the second game he
869 3. The stronger player removes his bishop.
871 4. The stronger player removes his rook.
873 5. The stronger player removes his rook and left lance.
875 6. The players play a two-game match; in the first game the stronger
876 player removes his rook and left lance (on 1a), while in the
877 second game he removes his rook and bishop.
879 7. The stronger player removes his rook and bishop. This is usually
880 called a "two-piece" handicap.
882 8. The stronger player removes his rook, bishop, and both lances.
883 This is called a "four-piece" handicap.
885 9. The stronger player removes his rook, bishop, both lances, and both
886 knights. This is called a "six-piece" handicap.
888 10. The stronger player removes his rook, bishop, both lances, both
889 knights, and both silvers. This is called an "eight-piece"
894 Another advantage of playing handicap games is that the handicaps
895 alter the optimal strategy for both players. For instance, handicaps
896 all have their own opening lines which may bear little or no
897 resemblance to those used in non-handicap shogi. This means that when
898 learning handicap shogi, you are essentially learning completely new
899 games which use the same equipment!
901 The reader may wonder how on earth a player giving an eight-piece
902 handicap, say, could possibly hope to win. Don't forget, though, that
903 in shogi the opponent's pieces can be captured and then become part of
904 one's own army. Thus, if the opponent plays badly enough, the number of
905 pieces will soon even out.
908 File: gnushogi.info, Node: Notes for chess players, Prev: Handicaps, Up: The rules of shogi
910 Notes for chess players
911 -----------------------
913 Here are a few miscellaneous things that may confuse chess players.
914 Some of these have been mentioned elsewhere, but they bear repeating.
917 1. There is no queen.
919 2. Pawns capture the same way they move. There is no initial
920 two-space pawn move and no _en-passant_ move.
922 3. There is no special castling move. There _are_ a large number of
923 possible defensive formations referred to as "castles" (*note
924 Sample game::.) but there is no need for special moves to create
927 4. A given piece can only promote to _one_ other kind of piece.
932 File: gnushogi.info, Node: Sample game, Next: Mating problems, Prev: The rules of shogi, Up: About shogi
937 This game was annotated by Pieter Stouten (*note References and
938 links::.). I have made some minor corrections. Note that captures are
939 denoted by the "x" symbol e.g. Rx3f and drops are denoted by the "*"
940 symbol e.g. R*3f. Check is indicated by a "+" after the move, e.g.
941 R3f+. I recommend you use gnushogi/xshogi to play along with this
942 game. In xshogi simply hit the "Force Moves" button after starting up,
943 while in gnushogi enter the word "force" at the prompt. This will
944 allow you to enter moves for both sides.
946 Note also that the move numbering system used here is the chess-type
947 system where one move means one move by each player. The Japanese count
948 one move made by each player as two moves.
950 --------------------------------------------------------------------------
952 Below you will find (the English translation of) an annotated game
953 which was published in the Dutch Shogi magazine "81" and in the Dutch
954 beginners booklet. It has proven to be a very useful game to explain
955 some basic principles of Shogi. Also, it is a rather straightforward
956 game compared to professional games where in most cases very diffuse
957 middle game fights take place.
959 Pieter Stouten, 14th May 1990.
961 --------------------------------------------------------------------------
963 Black: Michael Trent (1-dan). White: David Murphy (2-dan).
965 1. P2f P3d 2. P2e B3c
966 [ This move is necessary, as otherwise white can exchange pawns: 3. P2d
967 Px2d 4. Rx2d. He would thus get a pawn in hand and open up his rook
971 [ White closes the bishop diagonal again. He plans to play ranging rook
972 (the rook goes to 5b, 4b, 3 or 2b; a defensive strategy) and in that
973 case he'd better avoid an exchange of bishops. One of the reasons is
974 that he will have problems developing his pieces without leaving holes
977 4. S4h R3b 5. P3f S4b 6. K6h K6b
978 [ In general the rook plays an important role in the attacks. It is
979 wise to move the king away from the area where the initial fights will
980 be and both players act according to the Shogi proverb "keep the rook
983 7. K7h K7b 8. P5f P5d 9. G4i-5h G4a-5b
984 [ Both players use their second gold general to build their castle. ]
987 [ In itself this move is not bad. However, it will become clear that
988 black plans a quick attack and in that case it is wiser to omit this
991 10... S5c 11. P1f P1d
992 [ The advance of the edge pawns must be timed very well. The remark at
993 black's tenth move applies here too: this move is good if black wants to
994 play a slow game, because it eliminates a future B1e. ]
996 12. P4f K8b 13. N3g S7b
997 [ Black develops his knight in order to start an attack over the second,
998 third and fourth files. White strengthens his king's position and
999 awaits the attack. He aims at a counterattack as soon as black has
1000 broken through into the white camp. Probably white's breakthrough will
1001 take place later, but he has good compensation in the form of a stronger
1002 castle. This theme occurs very often in static rook versus ranging rook
1006 [ Black starts his attack and white puts up a very passive defence. His
1007 rook has a hard task now to penetrate the black position. Moreover, he
1008 blocks his own bishop. It seems much better to start a counterattack
1009 with 14... P3e, later to be followed by B2b, B5a or Bx4d in order to use
1010 his rook more actively. ]
1012 15. Px4d Sx4d 16. P*4e S5c
1013 [ 16... Sx4e is more active. A silver general is normally more valuable
1014 than a knight, but white gets two pawns in hand and black none, while
1015 the knight might come in handy for white too. ]
1017 17. Bx3c+ Nx3c 18. P2d Px2d
1018 [ Black threatens to break through and white has to consider taking the
1019 pawn on 2d or starting a counterattack with Nx4e. If he chooses the
1020 latter, black can play Px2c+ followed by +P3c. The disadvantage is the
1021 black "tokin" (=promoted pawn) that white will get in his camp; the
1022 advantage is that it will cost black two more moves to promote his rook.
1023 Because white did not trust that the result after engaging in a
1024 "semeai" (=mutual attack) with 18...Nx4e would give a positive result,
1025 he captured the pawn on 2d. Making the right decision in moments like
1026 this often makes the difference between a win and a loss: miss one
1027 attacking chance and you will be forced to defend the whole game until
1028 the unavoidable defeat; on the other hand, an unsound attack can destroy
1029 all "aji" (=potential, meaning possibilities, threats) without getting
1030 anything in return. ]
1032 19. Rx2d Nx4e 20. Nx4e Rx4e 21. R2a+ P*4g
1033 [ Now it becomes clear why black's 10. S6h was not good. Had this move
1034 been omitted, then white would not have had the time to play 13... S7b
1035 and after R2a+ the gold on 6a would hang. Thus black would have kept
1036 "sente" (=initiative). Instead of 21... P*4g, B*6d is a very good
1037 move, because after 22. P*2h black does not have a pawn in hand anymore
1038 and he is being threatened with the annoying 22... N*4f 23. G5g N3h+
1039 24. S4g +N4h also. Black can also counter 21... B*6d with 22. N*3g.
1040 White would then reply with 22... R4b 23. B*3c P*4g 24. Bx4b+ Sx4b. The
1041 white rook has played its role and instead of spending moves on saving
1042 it white starts to scatter black's defences by successive pawn drops on
1043 the fourth file: 25. Gx4g P*4f 26. G5g N*6e 27. G5h P4g+ 28. Gx4g P*4f.
1044 This analysis was provided by Kato Hifumi, 9-dan professional (the
1045 highest regular grade). Destroying the coherence of the enemy pieces
1046 (their shape) by dropping pawns is one of the most important Shogi
1047 techniques. With the actual move 21... P*4g white missed a good
1050 22. Sx4g P*4f 23. B*3g Px4g+ 24. +Rx6a +Px3g
1051 [ 23. B*3g seems pointless, but a closer look reveals that it is
1052 actually quite mean. On move 24 white cannot capture black's "Ryu"
1053 (=dragon =promoted rook) with his silver: 24... Sx6a 25. N*7d K7b 26.
1054 G*8b mate. By attacking the front of the white castle and threatening
1055 to mate him there, black has the chance to break down the white
1056 defences from the side. ]
1059 [ Here 25... B*4d would be much better, because it is defensive and
1060 attacking at the same time. After e.g. 26. G*4c Bx9i+ 27. Gx5c black
1061 threatens 28. +Rx7b Kx7b 29. S*6a K8b 30. S*7a Kx7a 31. G*7b mate.
1062 White is one move quicker, however. He has the following beautiful
1063 "tsume" (mating sequence where every move is check): 27... N*8f 28. Px8f
1064 S*8g 29. Kx8g B*9h 30. K7h Bx8i+ 31. K8g +B8i-8h 32. K9f L*9e mate.
1065 This illustrates the sharpness of Shogi: one move can make the
1066 difference between winning and losing. ]
1069 [ This move eliminates white's last chances. 26... R4b 27. +Rx4b Sx4b
1070 28. R*4a seems annoying, but after 28... B*3c 29. S7g B*3b white wins
1071 the rook and with his "tokin" on 3g there still is some hope. ]
1074 [ White cannot defend anymore, so he starts a desperate attack. Black
1075 does not lose the right track, however. ]
1077 28. Nx5c+ +Px5h 29. +Nx6b +Px6h 30. Gx6h N*8f 31. Px8f B*6i 32.
1078 Gx6i R4h+ 33. N*6h +Rx6h 34. Gx6h S*8g 35. Kx8g N*9e 36. K7h
1080 [ White resigns here, because after 36... B*8g 27. K7g his attack has