Shogi strategy and tactics

Starting position of shogi game

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

The basic tactics of shogi are similar to those of chess, involving forks, pins, removing the defender and other techniques, all of which are considered very strong when used effectively.

頭金 Head-Gold
 
△ Pieces-in-hand: none
▲ Pieces-in-hand: none
 
 
頭金 Head-Gold checkmate via promotion
 
△ Pieces-in-hand: none
▲ Pieces-in-hand: none
 
i. S-5b+

頭金 Head-Gold
 
△ Pieces-in-hand: none
▲ Pieces-in-hand: 金
 
 
頭金 Head-Gold checkmate via drop
 
△ Pieces-in-hand: none
▲ Pieces-in-hand: none
 
i. G*5b

Castles

There are several strong defensive fortifications known as castles. There are many variations and types of castles which can be used, but it is essential to understand which ones are useful in the current situation and how to compensate for its weak points.

Yagura

金矢倉 Gold Yagura

カニ Crab

The Yagura castle (矢倉囲い yagura gakoi, a yagura is a tower structure in Japanese castles) is considered by many to be the strongest defensive position in shogi.[1] It has a strongly protected king; a well-fortified line of pawns; and the bishop, rook, and a pawn all support a later attack by the rook's silver or knight. It is notoriously difficult to break down with a frontal assault, though it is weaker from the side. It is typically used against static rook openings that involve advancing the rook's pawn. However, one's opponent may just as easily adopt this defense, giving neither side an advantage.

There is a good deal of flexibility in the order of moves when building the Yagura defense, and the possibilities will not be listed here. The only point to keep in mind is that the generals should move diagonally, not directly forward.[1] However, there is a strong intermediate position called the Crab castle (カニ囲い kani gakoi).[1][2] It has the three pawns on the left side advanced to their final Yagura positions, and on the second rank all four generals are lined up next to the bishop, which is still in its starting position: 角金銀金銀 bishop-gold-silver-gold-silver. The king is moved one square to the left, behind the middle silver. The crab name comes from the way the king at 6i can only move from side to side (7i, 5i).

While forming the castle, the rook's pawn is often advanced two squares in preparation for a climbing rook assault on the opposing king. Another common preparation is to advance the adjacent silver's pawn square, allowing passage for both the rook's silver and knight. These offensive moves are not properly part of the castle, but the two-square pawn advance must be carried out early if there is to be room for it, and so it is often done while still castling.[1]

A common attack against the Yagura defense is to advance the rook's knight directly forward, defended by the rook and with a pawn in hand, to attack the fortifications on either side of the castled king.[1] If the defender has answered a lance's pawn advance on that side, a pawn may be dropped where the edge pawn had been. If the defending silver has moved or is not yet in position, a pawn may be dropped there.

銀矢倉 Silver Yagura

片矢倉 Half Yagura

Although Gold Yagura castle is very common, there are several variants of Yagura. A Silver Yagura uses a silver on 6g instead of a gold.[3] This allows for defending of the gold on 7h, which is only defended by the king in a Gold Yagura. Silver Yagura allows for greater flexibility with two silvers on the g rank. In a Gold Yagura, if the silver on 7g moves to 7f, it is not be able to return 7g, and if the gold on 6g moves to 7f, it can't move back to 7g. Using two silvers on 7g and 6g allows for the same range of defense on 8f, 7f, 6f, and 5f as well as the greater potential of both silvers returning back to 7g and 6g after moving up to the f rank. However, by using a second silver for the castle, one gives up the use of the silver for offensive purposes.

A Half Yagura has the king and the gold on 7h and 6h, respectively, instead of the positions 8h and 7h as in the usual Yagura castles. This positioning is meant to protect from the opponent's bishop being dropped onto 6i or 5i (highlighted in diagram) as now the gold on 6h is defended by the silver on 7g and the gold on 6g and the gold on 6h can attack 6i.[4][3] In a Gold Yagura, the gold on 6h is not defended by any piece besides the king, and it cannot attack a bishop that was dropped on 6i. A Half Yagura is also known as Amano Yagura (天野矢倉), named after Edo period shogi master Soufu Amano (天野宗歩).

Mino

美濃 Mino

A defensive position that is considered easier for beginners, but still popular with professionals, is the Mino castle (美濃囲い Minō gakoi). The King is placed in a safe position, while the three generals work well to back each other up. This is sometimes used when a player chooses a bishop opening rather than the rook-pawn opening.[5]

The Mino castle takes six steps to complete, not necessarily in this order:[6]

  1. Move the rook to the left side of the board. This move must be first.
  2. Move the king to where the rook started, three moves.
  3. Move the right-side silver general up one space, so it is now adjacent to the king.
  4. Move the left-side gold general diagonally up and right so that it is protected by the other gold general, which has not yet moved.
  5. (Optional) Move the edge pawn one square forward. This gives the king an escape route in the endgame.
  6. (Optional) Move the fourth file pawn one square forward, so that the left-side gold can be moved diagonally up and right once again. This strengthens the castle against attacks from the front and allows further piece development.

In modern Shogi against static rook, the preferred order is to push the edge pawn and build the castle first, before moving the king. If static rook considers Anaguma, then ranging rook has the option of making a rapid attack, while leaving the king on its initial square. If static rook chooses a rapid attack himself, then ranging rook will start moving the king into the castle.

High Mino

The High Mino castle is a natural development from Mino castle. Compared to Mino, it allows the player a greater potential for offense on the right side of the board and is stronger at the top although somewhat weaker from the side. It is created from Mino, by pushing the 4th file pawn up to 4f (if it hasn't already) to make way for the gold that moves from 5h. The 3g pawn also moves up to 3f to allow space for the knight.[6] Moving the knight to 3g is optional but common.

高美濃 High Mino

Silver Crown

The Silver Crown castle (銀冠 ginkanmuri) is often a further development from High Mino. From High Mino, the pawn above the king moves to 2f allowing the silver to position itself at the head of the king (2g). Then, the gold on 4i moves to 3h.[6] A silver crown can also be built on the left side.

銀冠 silver crown

Left Mino

Left Mino (左美濃 hidari Minō) can be formed in a similar way to the right-side Mino. However, there is also a common Left Mino variant that positions the king above the bishop's head, which allows the king to stay out of the diagonal of the opponent's bishop as shown below.[7]

左美濃 Left Mino

Anaguma

振り飛車穴熊 Ranging Rook Anaguma

居飛穴熊 Static Rook Anaguma

A third defense often used in professional shogi is the Anaguma (穴熊 lit. "bear in the hole", and which means "hibernating bear".[lower-alpha 1]), commonly called the "bear in the hole" castle in English (穴熊囲い anaguma gakoi). This castle can be executed on either side of the board, i.e. either by a player utilizing the ranging rook strategy or by a player employing the static rook strategy. The end-result will place the king in the corner square where the lance started, defended by two gold generals and one silver. This way, the King cannot be easily checked by a knight or a ranging piece.[8]

One suggested strategy for a rook-side castle is:

  1. Move the rook to the sixth or seventh file.
  2. Move the king to the rook's starting square.
  3. Move the lance up one square, then move the king to the lance's starting square.
  4. Move the silver general up and right.
  5. Move both gold generals to the castle for additional defense.

When building a left side Anaguma (with a static rook opening), the bishop is moved out of the way of the king, and the 7th file pawn is moved to make space for the bishop, which may be moved elsewhere later.[8]

Boat

船 boat

The Boat castle (舟囲い funagakoi) is a static rook castle used against ranging rook, where the king moves next to the bishop and moves the right hand gold diagonally forward above the king's throne. This castle can also be an intermediary towards making stronger castles, such as Left Mino, Silver Crown or Anaguma.[7] This castle is often considered weak, although static rook has the option of engaging in a rapid attack through various means, especially against 4th file rook and by making use of the left-hand silver.

A rapid attack isn't guaranteed to be successful, since ranging rook will try to trade off the bishops and bring the game into a full-scale battle. This can lead static rook into a difficult game, because his Boat castle is too weak compared to the opponent's Mino castle. As such, static rook would rather resort to making stronger castles, such as Anaguma.

Kabuto

The Kabuto castle is a structure often used to protect the king while playing a reclining silver strategy (腰掛け銀 koshikakegin) usually in combination with a bishop-exchange opening.[4] If bishops have already been exchanged, then the silver that originated originated at 7i will have moved up to 7g via 8h. And, for reclining silver, the silver that originated at 3i will have reached the central file at 5f (through 3h and 4g) with pawn on the fourth file moving up to 4f to make way for the silver. Reclining silver's name comes from the way the silver at 5f appears to sit on top of the 5g pawn and lean back against the 4f pawn. Kabuto is also known as Kabuto Yagura (カブト矢倉).

カブト Kabuto

Kabuto after bishop exchange and reclining silver in place
△ Pieces-in-hand: 角
▲ Pieces-in-hand: 角

Opening

The opening of shogi is generally slower than that of chess, due to the larger board and less mobile pieces. But since a quick offense will leave a player's home territory open to drop attacks as soon as pieces are exchanged, the aim of the opening is to build up defenses for the king, typically by moving the king to the side in a castle with three generals.[9] Leaving a king on its original square (居玉 igyoku or "sitting king") is a particularly dangerous position.[1][10]

Bishop opening
1. P-7f   ...

Rook opening
1. P-2f   ...

Both players can move the rook pawn forward (P-2f), or, more commonly, advance the pawn above and to the right of the bishop (P-7f). The former is known as a rook opening and the latter a bishop opening. With a bishop opening, it's common to exchange bishops by having one capture the other. This allows each player to put their newly captured bishop into play anywhere on the board, although care must be taken to avoid weaknesses in defense which may allow for a bishop drop. However, it is not advantageous to exchange bishops if your opponent has a better defensive setup, or more lines of attack. Moreover, making a bishop exchange constitutes one turn loss, so it's not advised without a good reason.

Many common opening attacks involve advancing a silver and ideally pawns, protected by other pieces. Because silvers have more possibilities for retreat, while golds better defend their sides, silvers are generally considered superior as attacking pieces, and golds superior as defensive pieces. It is common practice to defend the king with three generals, two golds and a silver.

Because defense is so important, and because shogi pieces are relatively slow movers, the opening game tends to be much longer in shogi than in international chess,[1] commonly with a dozen or more moves to shore up defenses before the initial attack is made.

Over many decades, Japanese professional players have all invented various jōseki (定跡), which determine moves and sequences which are thought to be the best for a particular situation. It also covers a branch of different variations within an intricate strategy, including alternative options and the certain consequences that some moves may bring.[11]

Openings are also classified as Static Rook (居飛車 ibisha) openings, where the offense is supported by the rook in its original position, and Ranging Rook (振り飛車 furibisha) openings, where the rook moves to the center or left of the board to support an attack there, typically with the idea of allowing the opponent to attack while arranging a better defense and aiming for a counterattack.[12] However, as the most powerful piece on the board, the rook invites attack, and in most cases, especially for weaker players, it is a good idea to keep the king well away from the rook.[1]

Openings are traditionally further categorized into based on the opening each player chooses:

  1. Double Static Rook (相居飛車 aiibisha) [that is, black Static Rook vs white Static Rook]
  2. Static Rook vs Ranging Rook (居飛車対振り飛車 ibisha tai furibisha)
  3. Ranging Rook vs Static Rook (振り飛車対居飛車 furibisha tai ibisha)
  4. Double Ranging Rook (相振り飛車 aifuribisha)

For each general static or ranging rook classification, there are many different opening types with traditional josekis.

Static Rook

Static Rook
2nd File
 
△
▲
Static Rook
4th File
 
△
▲
Static Rook
3rd File
 
△
▲

Climbing Silver

The Climbing Silver (棒銀 bōgin, literally "pole-silver") attack involves advancing a silver upward along with an advanced or dropped pawn supported by the rook aiming to break through the opponent's camp on their bishop's side.[1] Many different static rook opening variants include a climbing silver component. For instance, Climbing Silver can played as part of Double Wing Attack, Yagura, or Bishop Exchange openings. (However, there are other variants of these openings that don't include Climbing Silver.)

In the diagrams below, the black's silver advances to the e file.

Silver's starting position
 
△
▲
 
START
 
 
 
Silver to e rank (3e)
 
△
▲
 
i. S-3h
ii. S-2g
iii. S-2f
iv. S-3e
Silver to e rank (1e)
 
△
▲
 
i. S-3h
ii. S-2g
iii. S-2f
iv. S-1e

Once the silver has reached the e file (S-1e in the diagram directly below), black can attempt to attack white's bishop pawn at 2c by advancing their pawn (P-2d). White can capture black's pawn, but the silver can recapture white's pawn. Because white did not properly defend their bishop's head here, white's camp is somewhat weaker and more susceptible to subsequent attacks from black.

Pawn attack on bishop's pawn (2c)
 
△ Pieces-in-hand: none
▲ Pieces-in-hand: none
 
i. S-3h   ...
ii. S-2g   ...
iii. S-2f   ...
iv. S-1e   ...
v. P-2e   ...
 
Pawn exchange, Silver advance to 2d
 
△ Pieces-in-hand:
▲ Pieces-in-hand: 歩
 
i. S-3h   ...
ii. S-2g   ...
iii. S-2f   ...
iv. S-1e   ...
v. P-2e   Px2e
vi. Sx2e   ...

Similarly, it's also possible to play Climbing Silver when black has no pawn on the second file. Here the silver can climb to the empty 2e square. And, if there's a pawn in hand, then that pawn can be dropped to 2d.

Silver to 2e
 
△
▲ Pieces-in-hand: 歩
 
i. S-3h
ii. S-2g
iii. S-2f
iv. S-2e
2d pawn drop
 
△
▲ Pieces-in-hand: none
 
i. S-3h
ii. S-2g
iii. S-2f
iv. S-2e
v. P*2d

Defending the Bishop's Head

It is important for both players to protect the bishop's head with the gold, rather than immediately push the rook pawn again. If either player ignores protecting the bishop after move 6, their bishop may get trapped by a pawn drop as shown for black's bishop in the diagram below.

Double Wing Attack Trap
without Black's gold protecting 7h
 
△ Pieces-in-hand: none
▲ Pieces-in-hand: 歩歩
 
1. P-2f   P-8d
2. P-2e   P-8e
3. P-2d??   Px2d
4. Rx2d   P-8f
5. Px8f   P*8g!

A similar issue occurs in a Bishop Exchange opening where if bishop's head is not protected by a gold, then a pawn drop can occur.

Yagura josekis

Yagura
up to move 4 
△
▲

Side Pawn Capture

(also translated as Side Pawn Picker)

Side Pawn Capture
up to move 11 
 
△ Pieces-in-hand: 歩
▲ Pieces-in-hand: 歩

Bishop Exchange

Bishop Exchange
up to move 4 
△
▲
Bishop Exchange
up to move 4 
△
▲

Double Wing Attack

Double Wing Attack is a Double Static Rook opening where both sides play Static Rook with the first several moves on each side being identical or very similar. Both sides advance their bishop pawns to the e rank. Then, golds are moved to defend each bishop's head. Next, black initiates a pawn attack on the second file leading to a pawn exchange involving the rook. White responds by dropping a pawn to 2c to push black's rook back.

Double Wing Attack
position after 4 moves
 
△ Pieces-in-hand: none
▲ Pieces-in-hand: none
 
1. P-2f   P-8d
2. P-2e   P-8e
Double Wing Attack
position after 6 moves
 
△ Pieces-in-hand: none
▲ Pieces-in-hand: none
 
3. G-7h   G-3b
 
Double Wing Attack
position after 7 moves
 
△ Pieces-in-hand: none
▲ Pieces-in-hand: none
 
4. P-2d   ...
 
Double Wing Attack
position after 10 moves
 
△ Pieces-in-hand: none
▲ Pieces-in-hand: 歩
 
4. ...   Px2d
5. Rx2d   P*2c

After move 10 of Double Wing Attack, the joseki branches off into different variants depending on which square the rook moves down to. In the Floating Rook variant (浮き飛車 ukibisha), the rook moves to 2f. In the Retreating Rook variant (引き飛車 hikihisha), the rook returns to 2h.

Double Wing Attack Retreating Rook

After black's rook has retreated, white plays a similar sequences of moves: pawn exchange and a pawn drop by black.

Double Wing Attack Retreating Rook
position after 11 moves
 
△ Pieces-in-hand: none
▲ Pieces-in-hand: 歩 

6. R-2h   ...
 
Double Wing Attack Retreating Rook
position after 12 moves
 
△ Pieces-in-hand: none
▲ Pieces-in-hand: 歩
 
6. ...   P-8f
 
Double Wing Attack Retreating Rook
position after 16 moves
 
△ Pieces-in-hand: 歩
▲ Pieces-in-hand: 歩
 
7. Px8f   Rx8f
8. P*8g   R-8d

A common variant of Double Wing Attack Retreating Rook is for black to play Climbing Silver.

Other variants of Double Wing Attack Retreating Rook include Reclining Silver.

Double Wing Attack Floating Rook
Double Wing Attack Floating Rook
position after 11 moves
 
△ Pieces-in-hand: none
▲ Pieces-in-hand: 歩 

6. R-2f   ...

Ranging Rook

Ranging Rook
8th File
 

Ranging Rook
7th File
 

Ranging Rook
6th File
 

Ranging Rook
5th File
 

Many of the Ranging Rook strategies are named from the white/gote's perspective. For instance, the Third File Rook opening is named third file because when white moves their rook into position, their rook will end up on the third file (R-3b). If the same Third File Rook opening was played by black, then black's rook will move to the seventh file (R-7h). Similarly, the Third File Rook opening moves the rook second file (R-3b) for white while the position played by black is the eighth file (R-7h). (However, this opening nomenclature is different for the Right Fourth File Rook opening (a Static Rook opening). Right Fourth File Rook played by white moves their rook to the sixth file (R-6b) while the same opening played by black actually does move their rook to the fourth file (R-4h). Thus, the generalization is that Ranging Rook openings are named from white's perspective while the Static Rook opening is named from black's perspective.)

The Opposing Rook opening moves a rook to the same file as the opponent's rook. For white, this Opposing Rook position is the second file (R-2b) while the position played by black is the eighth file (R-8h).

Fourth File Rook

Fourth File Rook (Black)
 
△
▲
Fourth File Rook (White)
 
△
▲

Third File Rook

Third File Rook (Black)
 
△
▲
Third File Rook (White)
 
△
▲
Ishida Style (Third File Rook)
 
△
▲
 
(with Mino castle)
Quick Ishida (Third File Rook)
 
△
▲

Opposing Rook

Opposing Rook (White)
 
△ Pieces-in-hand: none
▲
Opposing Rook (White)
 
△ Pieces-in-hand: none
▲
Opposing Rook (White)
 
△ Pieces-in-hand: 角
▲
Opposing Rook (White)
 
△ Pieces-in-hand: 角
▲


Opposing Rook (Black)
 
△
▲
Opposing Rook (Black)
 
△
▲

Middle game

Professional shogi players tend to evaluate the flow of the game, that is, the sequence of moves leading to the current position and its likely development, much more than chess players.[13]

Because pawns attack head on, and cannot defend each other, they tend to be lost early in the game, providing ammunition for such attacks. Dropping a pawn behind enemy lines, promoting it to a tokin (gold general), and dropping a second pawn immediately behind the tokin so that they protect each other makes a strong attack; it threatens the opponent's entire defense, but provides little value to the opponent if the attack fails and the pieces are captured.

Players raised on international chess often make poor use of drops,[1] but dropping is half the game. If a player has more than a couple of captured pieces in hand, it is likely that dropping attacks are being overlooked. However, it is wise to keep a pawn in hand, and often to exchange pieces if necessary to get one.[14] Compared with international chess players, shogi players are more likely to sacrifice pieces, even powerful ones, if the resulting capture can be dropped back into play for a specific purpose.[15]

Attacking pieces can easily become trapped behind enemy lines, as the opponent can often drop a pawn on a protected square to cut off the line of retreat. For this reason, rooks, which can retreat in only one direction, are commonly kept at a safe distance in the early parts of the game, and used to support attacks by weaker pieces. However, once the game has opened up, a promoted rook is an especially deadly piece behind enemy lines.

Advancing a lance pawn can open up the side of the board for attack. Therefore, when a player first advances a lance pawn, it is common, though not obligatory, for the opponent to answer by advancing the opposing pawn, in order to avoid complications later in the game. It also allows the king to escape if attacked from the side.

End game

The collapse of one side's defense marks the beginning of the end game. Once a player has broken through the enemy lines, the opponent's king can be easily trapped by its own pieces. A common last-ditch defensive tactic is to open the pawn line to allow the king to escape. Kings are more difficult to checkmate in the open, especially if the opponent does not have many ranged pieces in play.

In the endgame, it comes down to a race over who can checkmate the opponent first. A tactic known as speed counting plays an important role in the endgame. By counting the number of moves until checkmate (assuming the opponent doesn't get to move) for both Black and White, this will help to influence decisions on whether to attack or defend. A simple mistake can change the flow of the game drastically. Among this, there are many other delicate factors to look out for within the endgame, including sacrificial attacks and traps.

A player's endgame play is strengthened by training on tsumeshogi.

Notes

  1. ↑ "badger" is a homonym

References

  1. 1 2 3 4 5 6 7 8 9 10 Fairbairn 1984.
  2. ↑ Hosking 1997, p. 46, Part 1, Chapter 8: Castles.
  3. 1 2 Hosking 1997, p. 47, Part 1, Chapter 8: Castles.
  4. 1 2 柿沼, 昭治 (1979). Shōgi ni tsuyoku naru hon 将棋に強くなる本 [Becoming Strong at Shogi] (in Japanese). 金園社 [Kin-ensha]. p. 29. ISBN 978-4321-55222-6.
  5. ↑ Hosking 1997, pp. 49–50, Part 1, Chapter 8: Castles.
  6. 1 2 3 Hosking 1997, p. 50, Part 1, Chapter 8: Castles.
  7. 1 2 Hosking 1997, p. 52, Part 1, Chapter 8: Castles.
  8. 1 2 Hosking 1997, p. 53–54, Part 1, Chapter 8: Castles.
  9. ↑ Jonathan Schaeffer, Martin Müller, Yngvi Björnsson (2003). Computers and games: third international conference, CG 2002, Edmonton, Canada, July 25–27, 2002: revised papers. Springer. p. 175.
  10. ↑ Hosking 1997, p. 42, Part 1, Chapter 7: Balancing Attack with Defense.
  11. ↑ Hosking 1997, p. 29, Part 1, Chapter 5: Introduction to Shogi Strategy and Tactics.
  12. ↑ Hosking 1997, pp. 43–45, Part 1, Chapter 7: Balancing Attack with Defense.
  13. ↑ Ito, Takeshi; Matsubara, Hitoshi; Grimbergen, Reijer (2004). "Shōgi no Ninchi Kagakuteki Kenkyū (2) Tsugi no Itte Jikken kara no Kōsatsu" 将棋の認知科学的研究(2)次の一手実験からの考察 [A Cognitive Science Approach to Shogi Playing Processes (2)-Some Results on Next Move Test Experiments]. 情報処理学会論文誌 [Transactions of Information Processing Society of Japan] (in Japanese) (Information Processing Society of Japan) 45 (5): 1481–1492. ISSN 0387-5806.
  14. ↑ Hosking 1997, p. 34, Part 1, Chapter 5: Introduction to Shogi Strategy and Tactics: "The pawn therefore has a vital role to play in both attack and defense. Having no pawn in hand (fugire), while one's opponent does have at least one pawn in hand, is clearly a disadvantange, and can be a very serious disadvantage."
  15. ↑ Hosking 1997, p. 23, Part 1, Chapter 4: Comparison of Shogi with Chess.

Bibliography

Further reading

External links

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