Castles · 兜矢倉
Helmet Yagura.
The Bishop Exchange castle: silver 7g, golds 7h and 5h, and the king between them on 6h, with a bishop in each player’s hand.
How it goes together
The front is the Yagura’s: the left silver on 7g, which got there by taking back the traded bishop, and the left gold on 7h behind it. The right gold does not climb to 6g as it would in a Yagura. It stays on 5h, where it covers more of the camp against a dropped bishop, and the king steps once, from 5i to 6h, so that it stands between the two golds. The 6g and 5g pawns stay at home, and 8h, where the bishop started, is empty. English sources call it the Helmet Fortress.
Move by move
This castle only exists once the bishops are off, so the order below is a real game with both sides’ moves: the Bishop Exchange line, the right silver to 4g, the edge pawns, then the king and the right gold on moves 23 and 25.
Step through the moves, or press play.
Tap a move to jump to it. Arrow keys work once the board has focus.
Most diagrams stop here, with the king on 6h. Given time it often walks on to 7i, and it can go all the way to 8h, but in this opening the fight usually starts before it gets there.
What it is good against
Dropped bishops. With both bishops in hand a castle is judged by the squares it leaves open, and this one leaves few: both golds cover 6g, the 7h gold holds the silver on 7g, and the fifth-file pawn stays at home, because pushing it gives a bishop dropped on 3i room to work. It is quick, too: in this line the castle costs two moves after the trade. And it can later grow into a Gold Yagura or a Dented Yagura (へこみ矢倉).
Where it breaks
It is a light castle. Against an attack from the side it is weaker than the Dented Yagura, with the king on 8h and the right gold beside the other on 6h, and the 6i square behind the king is covered by the king alone. It cannot always be deepened at leisure either: the fight often starts before the king reaches 8h, and a deeper king can end up nearer the opponent’s attack.
When to build it
In the Bishop Exchange, by both players, above all in the Reclining Silver lines, where both sides build for a long time before attacking. Climbing Silver and Rushing Silver players use it too, often half built, because their attack starts sooner. Recent professional games often keep the right gold on 4h instead of 5h, with the rook on 2i.
Build it at the board.
The app’s lesson walks the king into a Mino one step at a time, and its review names the castle you were building when a game turned.