Shogi strategy and tactics

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Even Game Initial Position
9 8 7 6 5 4 3 2 1
91 81 71 61 51 41 31 21 11 a
92 82 72 62 52 42 32 22 12 b
93 83 73 63 53 43 33 23 13 c
94 84 74 64 54 44 34 24 14 d
95 85 75 65 55 45 35 25 15 e
96 86 76 66 56 46 36 26 16 f
97 87 77 67 57 47 37 27 17 g
98 88 78 68 58 48 38 28 18 h
99 89 79 69 59 49 39 29 19 i

Shogi, like western chess, can be divided into the opening, middle game and endgame, each requiring a different strategy. The opening consists of arranging one's defenses and positioning for attack, the middle game consists of attempting to break through the opposing defenses while maintaining one's own, and the endgame starts when one side's defenses have been compromised.

Tactics[edit]

The basic tactics (手筋 tesuji) of shogi are similar to those of chess tactics, involving forks, pins, removing the defender and other techniques, all of which are considered very strong when used effectively. Other tactics, particularly ones involving dropped pieces, have no parallel in western chess.

Fork[edit]

A fork (両取り ryōtori) is a move that uses one piece to attack two or more of the opponent's pieces simultaneously, with the aim to achieve material advantage, since the opponent can counter only one of the threats.[1] (Cf. forks in western chess.)

Some forks have specific names in Japanese. A silver forking two pieces from behind is 割り打ちの銀 wariuchi gin "silver stabbing-in-the-back". A fork between a king and a rook is 王手飛車 (ōtebisha).

Pin[edit]

Bishop Pinning Pawn
Protecting Rook

 
9 8 7 6 5 4 3 2 1
91 81 71 61 51 41 31 21 11 a
92 82 72 62 52 42 32 22 12 b
93 83 73 63 53 43 33 23 13 c
94 84 74 64 54 44 34 24 14 d
95 85 75 65 55 45 35 25 15 e
96 86 76 66 56 46 36 26 16 f
97 87 77 67 57 47 37 27 17 g
98 88 78 68 58 48 38 28 18 h
99 89 79 69 59 49 39 29 19 i

A pin is when a defending piece that is attacked by a ranging piece cannot move without without exposing a more valuable piece behind it.[1] (Cf. pins in western chess and also cf. skewers.) In shogi, only lances, rooks (or dragons), and bishops (or horses) can pin an opponent's piece. In the example, the Black's pawn at 3g is pinned by White's bishop because if the pawn were to advance to 3f then Black's rook would be captured by the bishop.

Dangling pawn[edit]

A dangling pawn or hanging pawn, (垂れ歩 or たれ歩 tarefu) is a pawn that is dropped in a position in which it can promote (to a と tokin) in the player's next move.[2]

Although dropping a dangling pawn may not be an immediate threat to an opponent, the later threat of promotion can be a greater danger. For example, in the diagrams below, Black is attempting to break through White's camp along the second file at 2c with a dropped pawn supported by a rook on 2h. If Black drops the pawn on 2c, White can retreat their bishop to 3a and since the pawn can only attack forward it does not threaten Black's gold on 3c. In subsequent moves, Black cannot win the piece exchanges by promoting the pawn on the b rank (P-2b+) because White can start the attack and there are an equal number of pieces (gold and bishop vs pawn and rook). In contrast, if Black drops a dangling pawn to 2d and White does nothing to prepare, when the pawn promotes at 2c both White's gold and bishop will be attacked by the tokin.

Joining pawns[edit]

Joining pawns (継ぎ歩 tsugifu) is a tactic in which a pawn is sacrificially dropped at the head of an opponent's pawn in order to lure the opponent's pawn forward.

In the example diagrams, Black attacks White's pawn on 2c leading White to capture Black's pawn. Then, Black plays the joining pawn tactic forcing White to move to 2e. Since White's pawn is now at 2e it cannot be used to protect White's camp on the second file. Furthermore, since White cannot drop a second pawn on the second file, their defense is much weaker.

Additionally, the moved pawn also gives Black an option of dropping a dangling pawn on 2d, which cannot be immediately attacked by White. This joining–dangling pawn sequence corresponds to a shogi proverb: 三歩あったら、継ぎ歩とたれ歩 sanpu attara tsugifu ni tarefu "if you have three pawns, joining pawn and dangling pawn".[3]

Joining pawn tactics may be useful in damaging the structure of an opponent's castle.

Piece exchange and turn loss[edit]

When two pieces (usually identical) are captured by each side at the same coordinates, it is referred to as an exchange. (Cf. exchanges in western chess.) Since captured pieces are never removed from play, a piece exchange has the effect of putting the exchanged pieces in hand and a turn sacrifice for the player who initiated the exchange.

For example, in the diagrams to the right, Black has decided to capture White's bishop on 2b with their bishop on the seventh file (Bx2b). White responds by capturing Black's bishop with White's silver (Sx2b). In comparing the start and end board positions of this bishop exchange, one can see that this is as if Black and White both removed each of their bishops from the board and put them each in hand and then Black skipped their turn allowing White to advance their silver to 2b. For this reason, equal piece exchanges must weigh the pros and cons of losing a turn and gaining a piece in hand (all else being equal).

There is an opening known as One-Turn Loss Bishop Exchange, which is so-named because White, who already is slower to position their pieces since they have second move, intentionally skips their turn via a bishop exchange. This puts White behind two moves. (Of course, there is a strategical tradeoff in this move which allows White to position their pieces in way that isn't otherwise possible.)

Generals[edit]

Function and mobility[edit]

Golds are usually used to defend whereas silvers are used to attack.

Dancing Pawns[edit]