Yagura.

How it goes together

The rook stays home on the right, so the king goes left. Silver to 7g and gold to 6g make the front wall, the second gold on 7h stands next to the king on 8h, and the bishop, which started on 8h, has moved out of the way. It takes twelve moves, and in games where both sides keep their rooks home it is the most played castle there is.

Move by move

Black only, from the start position. Watch the order rather than the squares: the generals all go up first, and the king walks in last along the bottom rank.

The bishop is the reason for that order. It starts on 8h, the square the king is walking to, and with its own silver on 7g its only way out is 7i, the square the king has to pass through. Twelve moves, and they cannot be shuffled for convenience.

What it is good against

Solid from the front and against diagonal attacks, which is where a static rook opponent comes from. The 6g gold guards the 7g silver and the 7h gold guards them both, and the king has the 9i corner behind him if he needs it.

Where it breaks

Time. Twelve moves is a long while, and a half-built Yagura is a weak one; the whole art of the opening is building it without falling behind. Once built, the head of the 7g silver and the edge file are the usual points of attack.

When to build it

When both players keep their rooks on the right. Against a ranging rook it is the wrong shape; choose a Mino on the left, or a castle in the corner.

Other Yagura shapes

Japanese sources name more Yagura shapes than this site builds. Two have diagrams that several sources agree on; they are shown below as positions rather than builds, because no source gives a move order for them.

Dented Yagura (へこみ矢倉)

The king, the left gold and the silver stand as in a Gold Yagura, on 8h, 7h and 7g, but the right gold stays on the second rank at 6h, beside the 7h gold, and the 6g pawn stays at home. The two golds guard each other, so the 7h gold has a defender besides the king, and both guard the 7g silver; the 6h gold also covers 6i. Four diagrams agree on it square for square.

It sits lower than a Gold Yagura: Japanese teaching sites call it much stronger from the side and thinner on the diagonals, and shougi.jp adds that after a bishop trade it leaves fewer squares for a dropped bishop. It usually grows out of the Helmet Yagura in Bishop Exchange games, mostly as White’s castle, when the king walks on to 8h and the right gold steps across to 6h.

Push the sixth-file pawn to 6f and lift that gold to 6g, and it becomes a Gold Yagura.

Square Yagura (四角矢倉)

All four golds and silvers in a two-by-two block beside the king.

In the gold form a Complete Yagura’s right silver has come back to 6h, under the 6g gold; in the silver form a Silver Yagura adds the right gold on 6h. shogijugem calls the silver form one of the hardest four-piece Yagura, iron against attacks from the side, with the edge as its weak point; there the 6h gold covers 5g, 5h and 6i, squares a dropped bishop would use.

In the gold form the 7h gold is guarded by the king alone. No source gives a move order for either.

Three more names turn up in the same lists, each with too little behind it here for a diagram. Tofu Yagura (豆腐矢倉) is not a castle you build: the name is for a Gold Yagura that falls apart like soft tofu after a knight attack drives its silver off 7g. Flowing Yagura (流れ矢倉) sends the left silver to the centre instead of 7g, and its two sources disagree about what then stands on 7g. Straight Line Yagura (一文字矢倉) is a nickname for all four golds and silvers in one row, 7g to 4g, with the king behind them on 7h.