Castle (shogi)

Her opponent, Fusako Ajiki (White) was using an Incomplete Mino castle (on the right side of her board) that has been attacked forcing the silver previously on 72 to move to 61.

[2] The 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.

The Helmet or Headpiece (カブト, kabuto) castle is a structure often used to protect the king while playing a Reclining Silver strategy usually in combination with a Bishop Exchange opening.

Putting more emphasis on a wide defense than on solidness, the goal of the player using this castle is to prevent the opponent from dropping pieces into their camp.

Although feeble in appearance, the main characteristic of this castle is that as the formation is low the king has plenty of routes to escape from attacks coming from right or left.

In recent years attention has been paid to its use for sente (black) in Side-Pawn Capture openings, and some research has been conducted about the solidness of the king, and following this research the Right Nakahara variation, where the position of the pieces on left and right of the king are reversed, has become rarely used.

It is named after the long row of pieces on rank 8, which is like the shape of traditional Japanese paperweights used to hold down parchment paper for brushwork calligraphy.

The Boat castle [ja] (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.

A rapid attack is not guaranteed to be successful, since Ranging Rook will try to trade off the bishops and bring the game into a full-scale battle.

As such, Static Rook would rather resort to making stronger castles, such as Bear-in-the-hole or Left Mino.

Subsequently, the castle has been used by professional shogi players in 2018 and recently featured in a book on a new Anti-Ranging Rook Rapid Attack strategy.

The Skewered Cutlet is structurally similar to the Static Rook Bear-in-the-hole, but unlike the latter, the positions of the king and the lance are reversed.

Among its advantages is that since the king is away from the bishop's diagonal, it can easily escape towards the top from side attacks, and furthermore, that it can be formed in one less move than Bear-in-the-hole.

In contrast, it takes only two moves to convert into a Millennium castle, so care needs to be taken to use it properly depending on the circumstances.

The Mino castle (美濃囲い, minōgakoi) is a defensive position that is considered easier for beginners, but still popular with professionals.

Yasumitsu Satō (Black) used the Wall castle in a 2017 NHK tournament on October 22 as shown in the adjacent diagram.

The name "Millennium" is due to the fact that it first started to be deliberately played among professional players around the year 2000.

At the time, the Fujii System was making its fury felt, which unlike Bear-in-the-hole Static Rook made threats against the king difficult by way of the bishop and the knight, which consolidated it as a strong tactic.

The Millennium castle is characterized by the King being positioned in the place of the left knight, and surrounded by three (or four) golds and silvers.

Furthermore, the most important difference with Bear-in-the-hole is that since the king is not on the rival's bishop diagonal this makes it easy for the left knight to attack and capture.

Further, compared to the Bear-in-the-hole castle, due to its close proximity to the center, it shows weakness against attacks with promoted pawns.

This castle usually develops when one player tries to attack the other's Silver Crown from the side with rooks (or dragons).

Compared to Mino castles, the Gold Excelsior is stronger against attacks from above (especially those from the first and second file).

Gold Excelsior is also weak against attacks from the fourth file, which is often called "the rabbit's ear."

Ranging Rook games, in which side attacks are typical, Mino castles are superior.

In contrast, against side attacks in Double Ranging Rook games, Gold Excelsior is superior.

However, positions where a silver wall is formed have been falling out of favor recently due to their weaknesses against Fortress castles, and hence Mino has become more predominant even in Double Ranging Rook games.

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

In a Double Static Rook game from an April 1970 Meijin title match, challenger Renshō Nada [ja] (Black) used a Fourth Rank Edge King castle (which requires many moves to construct).

Yasuharu Ōyama initially used a Snowroof-like structure for his castle that later developed in response to Nada's position.