A castle 囲い is the formation you build around your king before the fighting starts. There are dozens, but three families cover most games. The diagrams show just the castle's own pieces.
Mino 美濃囲い
The ranging-rook player's castle, built on the right where the rook started. King on b2, silver c2, golds d1 and e2. It takes only a few moves and is very hard to break from the side, where a static-rook attack usually comes.
Yagura 矢倉
The classic castle when both players play static rook. The king sits on h2 behind a tall wall: golds g2 and f3, silver g3, pawns g4 and f4. Strong from the front, where a static-rook opponent attacks; slower to build than Mino.
Anaguma 穴熊
"Bear in the hole": the king goes all the way into the corner, behind its own lance, and the generals pack in around it. It takes the longest to build, but once complete it is widely considered the hardest king in shogi to mate — often the attacker needs to strip away three or four pieces first.
Choosing
| Castle | Speed | Strong against | Goes with |
|---|---|---|---|
| Mino | Fast | Attacks from the side | Ranging rook |
| Yagura | Medium | Attacks from the front | Static rook vs static rook |
| Anaguma | Slow | Almost everything, once built | Either |
A half-built castle is often worse than none: know how many moves yours needs, and count whether you have them.
To see how each castle is built move by move — and six more besides these three — use the castle reference.