Castle (shogi)

In shogi, castles (囲い gakoi) are strong defensive fortifications usually involving golds (金), silvers (銀), and pawns (歩) that protect the king (玉). Typically, they also require moving the king from its starting position – often to the left or right side of the board.

In contrast to the special castling move in western chess, shogi castles involving making multiple individual moves with more than one piece. The simplest castle involves two pieces and requires three moves, but it is more common to move at least three different pieces. For example, a simple Mino castle (美濃) requires moving the king, the rook (飛), a silver, and two golds for a total of six moves. Others such as the Static Rook Anaguma castle (振り飛車穴熊) are more complex, which requires moving the king, a pawn, the bishop (角), a lance (香), a silver, and two golds for a total of twelve moves.

There are many types of castles and variations on those types which can be used, but it is important to understand which ones are useful in the current situation and how to compensate for its weak points.

Castles and opening types

Certain castles are generally paired with certain openings. For example, if White is playing a Ranging Rook opening like Fourth File Rook, then White often uses a Mino (or related) castle on their right side of the board. A Fourth File Rook opening can be met with Black playing a Static Rook opening, which may often lead to Black building a Static Rook Anaguma castle.^[1]

Yagura

The Yagura or Fortress castle (矢倉囲い yagura gakoi) is considered by many to be the strongest defensive position in shogi in Double Static Rook games.^[2]

A common Yagura structure is the Gold Yagura (金矢倉 kin yagura). 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 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. A point to keep in mind is that the generals should move diagonally, not directly forward.^[2]

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.^[2]

Quick Yagura castle

Quick Yagura castle or Quick Yagura castling or Rapid Yagura castling (矢倉早囲い yagura hayagakoi) is a faster way of forming a Yagura castle than the standard way in that it saves one move. It is not a distinct castle but rather a method.

Quick Yagura castling will lead to the intermediate position seen in the adjacent diagram. This intermediate position does not occur when a Yagura is built using the slower traditional move sequence.

(The term 早囲い hayagakoi also refers to the Quick castle, also known as the Wall castle.)

Silver Yagura

Although the Gold Yagura castle is very common, there are several variants of Yagura. A Silver Yagura (銀矢倉 gin 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 and the side of silver (5g) is not defended.

Incomplete Yagura

An Incomplete Yagura or Half Yagura (片矢倉 kata 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) after a bishop exchange 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).

Right Yagura

A Right Yagura (右矢倉 migi yagura) is a Yagura castle built on the right side of the board instead of the traditional left side.

A Right Yagura may be useful in Double Ranging Rook positions since the Yagura structure is strong against attacks from above.

A demerit of Right Yagura is that it requires several moves to create.

A Mino castle may transition into a Right Yagura.

Other Yagura variants

There several other Yagura variants shown below.

• Complete Yagura (総矢倉 sōyagura)^[3]
• Diamond Yagura or Lozenge Yagura (菱矢倉 hishi yagura)
• Silver Standing Yagura or High Silver Yagura (銀立ち矢倉 gintachi yagura)^[3]
• Kikusui Yagura or Floating Chrysanthemum Yagura (菊水矢倉 kikusui yagura)
• Dented Yagura or Hollow Yagura (へこみ矢倉 or 凹み矢倉 hekomi yagura)
• Yagura Anaguma (矢倉穴熊)

Crab

When building a Yagura castle, there is a strong intermediate position called the Crab castle (カニ囲い kani gakoi).^[2][5] It has the three pawns on the left side advanced to their final Yagura positions, and on the h 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).

Bonanza

The Bonanza castle (ボナンザ) is a castle that used to be built by the computer shogi engine Bonanza. It has some similarities with the Incomplete Yagura castle.

Helmut

The Helmut or Headpiece castle (カブト 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 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 Helmut Yagura (カブト矢倉 or 兜矢倉 kabuto yagura).

Snowroof

Snowroof (雁木 gangi)

Right King

Right King (右玉 migi gyoku)

Central House

Central House (shogi) (中住まい naka zumai)

Nakahara

Nakahara (shogi) (中原囲い Nakahara gakoi)

Boat

The Boat castle (舟囲い or 船囲い 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.^[6] 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 their 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 or Left Mino.

Daddy's Dearest

Daddy's Dearest or Girl-In-The-House (箱入り娘 hakoiri musume, lit. "daughter inside box")^[7] is a development from the Boat castle with the fifth file gold moving to the sixth file getting closer to the king.

Diamond

The Diamond or Lozenge castle (菱囲い hishi gakoi) can be developed from a Boat castle by moving the left silver up to 6h and incorporating the right silver above the gold on 5g.^[6] The Diamond is relatively stronger than the Boat.

Yonenaga King

Yonenaga King castle (米長玉 Yonenaga gyoku) is used for Static Rook vs Ranging Rook games.^[8] This castle is named after Kunio Yonenaga.

This castle is similar to an Edge King Silver Crown.

The Yonenaga King variant show here is almost the same as a Left Silver Crown castle but with the king moved leftward one file to the edge. Thus, it may called by the name Yonenaga King Silver Crown (米長玉銀冠 yonenaga gyoku ginkanmuri).

Elephant Eye

Silver Elephant Eye (銀象眼 gin zōgan) and Gold Elephant Eye (金象眼 kin zōgan) may be be used in bishop handicap games.

Skewered Cutlet

Skewered Cutlet castle (串カツ kushikatsu) is used for Static Rook vs Ranging Rook games. It is named after a kushikatsu.

The Skewered Cutlet is structurally similar to the Static Rook Anaguma.

Anaguma

Anaguma castle or Bear In The Hole (穴熊 anaguma, lit. "hole-bear") castle is a very common and often used in professional shogi. (An anaguma is a Japanese badger.)

This castle can be executed on either side of the board. A player utilizing the Ranging Rook strategy uses a Ranging Rook Anaguma (振り飛車穴熊 furibisha anaguma) on the right side while a player employing the Static Rook strategy builds a Static Rook Anaguma (居飛車穴熊 ibisha anaguma) on the left side. 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.^[9]

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.^[9]

It's also possible for a gold to be positioned at 6g instead of 7h.^[10]

Anaguma variants

Mino

The Mino castle (美濃囲い minō gakoi or 本美濃囲い hon minō gakoi) is a defensive position that is considered easier for beginners, but still popular with professionals. (Mino is a historical province of Japan.) The King is placed in a safe position, while the three generals work well to back each other up. This is often used when a player chooses a Ranging Rook opening rather than a Static Rook opening.^[11]

The Mino castle takes five steps to complete, not necessarily in this order:^[12]

1. Move the rook to the left side of the board. This move is often first (although it is last in the Fuji System).
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 moved.
5. (Optional) Move the edge pawn one square forward. This gives the king an escape route in the endgame.

In modern shogi against a Static Rook position, the preferred order (as in the Fuji System) is to push the edge pawn and build the castle first, before moving the king. If the Static Rook opponent considers Anaguma, then a Ranging Rook player 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.

Another common variant also advances the fourth file pawn to 4f. This move reinforces the king's temple, the 3g square, from a bishop attack or defends from a knight being positioned on 5e also attacking the king's temple. It additionally makes way for a gold to advance to 4g in the development of a High Mino castle.

It is possible that a Mino castle can transition into a Right Yagura castle.

Incomplete Mino

Incomplete Mino or Half Mino (片美濃 kata Minō) is a Mino with the leftmost gold is missing.^[12]

This is commonly seen as a transitional state when building a regular Mino since the leftmost gold is usually the last piece to move in the formation sequence.

However, an Incomplete Mino is also built for strategies (such as Opposing Rook) that use the gold on the other side of the board (where the rook is positioned).

High Mino

The High Mino (高美濃 taka Minō) castle is a natural development from Mino castle when wanting to put pressure on a Static Rook opponent's castle or when being attacked from above as in a Double Ranging Rook game. 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.^[10]

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. This strengthens the castle against attacks from the front and allows further piece development.

A common such development is having the 3g pawn also move up to 3f to allow space for the knight.^[12] Moving the knight to 3g is optional but common. It's also possible to advance the fifth file pawn, which is defended by the 4f gold.

Silver Mino

A Silver Mino (銀美濃 gin minō) castle replaces the leftmost gold of a regular Mino castle with a silver.

When the leftmost silver is moved up from 5h to 4g as like the gold in a High Mino castle, this is also known as a Silver Mino. In this variant, the 3h is defended better, but the 5h square is now weaker.

As with the regular Mino, it's also standard to make an escape hatch for the king by advancing the first file pawn.

Silver Crown

The Silver Crown castle (銀冠 ginkanmuri) is often a further development from High Mino.

From a High Mino structure, 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 to take the silver's former square.^[12]

It is also typical for the knight to advance.

Silver Crown is stronger than both Mino and High Mino from above.^[10]

Silver Crown variants

A Silver Crown can also be built on the left side (Left Silver Crown 左銀冠 hidari ginkanmuri) for Static Rook positions.

A Left Silver Crown may also transition into a Left Silver Crown Anaguma (居飛車銀冠穴熊 ibisha ginkanmuri anaguma).

An Edge King Silver Crown (端玉銀冠 hashi gyoku ginkanmuri or hashi gyoku ginkan) has the king moved to the edge file. It is structurally similar to the Yonenaga King castle.

Kimura Mino

The Kimura Mino (木村美濃 kimura minō) castle was invented by player Yoshio Kimura.

In this variant, a gold 金 is positioned on 3h where the silver 銀 usually is and the silver is positioned where the gold usually is in a High Mino castle.

A Kimura Mino can be used with a Central Rook Silver Horns (ツノ銀中飛車 tsuno gin nakabisha) attacking formation.

Left Mino

Left Mino (左美濃 hidari minō) can be formed in a similar way to the right-side Mino with the king on 8h.

Castle Tower Mino

There is also a common Left Mino variant known as Tower Mino (天守閣美濃 tenshukaku minō) 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 to the right.^[6]

Another reason for this 8g king position is because it is faster to create: the usual right-side Mino castle has the king positioned on the second file from the edge. However, on the left side this position is occupied by the bishop, so extra moves are required to move the bishop out of the king's way.

Four-Piece Mino

Four Piece Mino (四枚美濃 yonmai minō)

Other Mino variants

• Gold Mino (金美濃 kin minō)
• Diamond Mino (ダイヤモンド美濃 daiyamondo minō)
• Top Knot Mino (ちょんまげ美濃 chonmage minō)
• Bald Mino (坊主美濃 bōzu minō)

Wall

Wall castle (壁囲い kabe gakoi), also known as Quick Castle (早囲い hayagakoi), is used for Static Rook vs Ranging Rook games. According to Hosking, it can also be called Edo Castle.^[8] It can be formed very quickly if under attack.

(In Japanese, the term 早囲い hayagakoi also refers to Quick Yagura castle.)

The Wall castle can develop later into the stronger Gold Mino with two moves.

Flatfish

Flatfish (shogi) (平目囲い or ヒラメ囲い hirame gakoi)

Millenium

Millenium (shogi) (ミレニアム mireniamu) is a newer castle developed in response to the Fuji System (藤井システム Fuji shisutemu) opening.

Twin Gold

Twin Gold (二枚金 nimaikin) is a castle used in Double Ranging Rook openings. ^[8] It's also called Peerless Golds (金無双 kinmusō).

Mid-Rank King castles

Aerial Tower

Aerial Tower (空中楼閣 kūchū rōkaku) is a Mid-Rank King (中段玉 chūdan gyoku) type of castle in which the king is positioned on the middle d-f ranks.

Fourth Rank Edge King

Fourth Rank Edge King (四段端玉 yondan hashigyoku) is a Mid-Rank type of castle.

See also

• Shogi strategy and tactics
• Shogi opening
• Castling (in western chess)

Notes

References

Bibliography

• Aono, Teruichi (2009) [First published in 1983]. Better Moves for Better Shogi. Translated by Fairbairn, John (2nd ed.). Ishi Press. ISBN 978-4-87187-999-6. 
• Fairbairn, John (1984). Shogi for Beginners. Ishi Press. ISBN 978-4-8718-720-10. 
• Hosking, Tony (1997). The Art of Shogi. The Shogi Foundation. ISBN 978-0-95310-890-9. 
• Kaneko, Takashi (2003). Storming the Mino Castle 200. Translated by Sams, Richard. Nekomado. ISBN 978-4905225058. 
• Nishio, Akira (2014). "4th-file rook vs. static rook (1)". Shogi Openings. 

External links

• Youtube: HIDETCHI's How to play shogi: Lesson #17 - Castles for Double Static Rook Opening
• Youtube: HIDETCHI's How to play shogi: Lesson #18 - Castles for Swinging Rook against Static Rook
• Youtube: HIDETCHI's How to play shogi: Lesson #19 - Castles for Static Rook against Swinging Rook
• Youtube: HIDETCHI's How to play shogi: Lesson #20 - Castles for Double Swinging Rook