Castles · 坊主美濃
Bald Mino.
A Half Mino with no pawn on the king’s file: the rook pawn was exchanged before the king castled, so nothing stands over his head.
How it goes together
The squares are the Half Mino’s: king 2h, silver 3h, gold 4i, with the knight and lance at home in the corner. What is missing is a pawn. Black pushed the rook pawn up the second file and exchanged it before castling, so no Black pawn is left anywhere on that file. The 3h silver and the 4i gold guard each other, and the silver still covers 2g, the square over the king, but no pawn stands there. 坊主 (bōzu) is a monk’s shaven head.
Move by move
Both sides’ moves, from the start position, because a pawn only leaves the board in an exchange. The first 22 are a Double Wing Attack line recorded by shogilounge.com, the same moves that open our Nakahara’s Rushing Silver page: Black exchanges the rook pawn on moves 7 to 9 and brings the silver to 3h on move 13. No source plays on into the castle, so the last five moves are ours: the king walks round the silver by 4h and 3i to 2h, and White’s two moves in between are ones the same source plays at that point against a different Black set-up.
Step through the moves, or press play.
Tap a move to jump to it. Arrow keys work once the board has focus.
Twenty-seven moves, fourteen of them Black’s. The rook is still floating on 2f, and Black has the exchanged pawn in hand to drop on 2g if the head needs it. ja.wikipedia and shougi.jp note that the king often stops on 3i instead.
What it is good against
Flexibility. With no pawn of its own on the second file, Black is free to drop one there, and ja.wikipedia notes that a pawn dropped on 2g makes it an ordinary Half Mino. Against an attack from the side it is still a Mino: the silver on 3h and the gold on 4i guard each other.
Where it breaks
The head. No Black pawn stands on the second file, so an attack down that file meets no pawn before it reaches the king. ja.wikipedia calls the head far weaker than a Half Mino’s, shogi-joutatsu calls it very thin, and Shogi Wars says it looks cold up there. It is also one gold short of a full Mino.
When to build it
After an early rook-pawn exchange, when the rook then goes to work away from the second file. ja.wikipedia names the Twisting Rook (ひねり飛車), in which Masuda Kōzō castled this way, with his rook on 7g, against Katō Hifumi and Nakahara Makoto; shogi-joutatsu names the feint ranging rook (陽動振り飛車), and shougi.jp the Double Wing games that turn into a Twisting Rook. It is mostly Black’s castle, because the Twisting Rook is mostly Black’s opening. Put a pawn back on 2g and it is a Half Mino.
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.