Anaguma Castle: Shogi's Corner Fortress, Move by Move
The Anaguma, meaning badger hole, is shogi’s maximum-security castle. The king crawls into the corner square 9i where the lance started, sealed in by the lance on 9h, a silver on 8h, and a gold on 7i. It is the hardest standard castle to checkmate.
What the Anaguma Castle is
Every other castle shelters the king. The Anaguma buries it. The lance steps forward to 9h, the king slides underneath into the actual corner, and then the wall goes up behind it: silver to 8h, gold to 7i, with the knight on 8i already part of the masonry. No square next to the king is empty, so there is nowhere to drop a check.
That last point is the castle’s real gift. In shogi, danger arrives as much from the opponent’s hand as from the board, and a king with no adjacent landing squares is immune to the drop checks that end most games. While the Anaguma stands, its owner attacks with a freedom no other castle allows, trading pieces and inviting complications that would be suicidal with an exposed king. Material handed to the opponent cannot easily come back as a check.
The price is paid up front. The dig takes eleven of your own moves in the line shown here, during which the opponent does whatever they like. And the corner is a one-way door: if the wall is ever breached, the king has no escape route at all. Anaguma games tend to be won cleanly or lost completely.
Watch it get built
The replay below shows the full dig from the starting position. Notice the choreography: the bishop diagonal is handled first, the king starts walking early, and the lance-up, king-under shuffle comes only when the coast is clear. Step through it and watch the corner seal shut.
Strengths and weaknesses
Strengths
- The king hides in the corner behind a lance, knight, silver, and gold: the hardest castle to mate.
- No checks are possible for a long time, so you can attack with total freedom elsewhere.
- Trading pieces usually favors the anaguma side because dropped pieces cannot easily reach the king.
Weaknesses
- Takes many moves to build, giving the opponent a free hand in the opening.
- Once the fortress is breached it is hard for the king to escape the corner.
- The edge above the castle is a lever: a well-timed 9e pawn break can crack it open.
When to choose it
The Anaguma’s classic home is the Static Rook side of a Static Rook against Ranging Rook game. The enemy rook points at one wing, so the Static Rook player burrows in on the far side of the board from it and wins the attacking race that follows. That version, the Static Rook Anaguma, is one of the most feared weapons in that ancient matchup. Ranging Rook versions exist too.
Choose it when you have the patience to finish it and a plan for the free moves you are handing over. Against it, the standard advice applies in reverse: attack before the digging finishes, or squeeze the corner from a distance and lever the edge with a well-timed pawn break on 9e.
Best against: Ranging Rook setups; the Static Rook player burrows in on the far side from the enemy rook and wins the attacking race.
Pairs with: Static Rook. See the openings guide for how the opening and the castle fit together.
The other castles
Yagura Castle
Other Static Rook openings, where both kings castle on the same side and the fight happens on the far files.
Mino Castle
Static Rook attacks from the front; the castle faces sideways, so frontal pressure hits its strongest wall.
Or compare all three side by side in the castles guide.
FAQ
What is the Anaguma castle in shogi?
The Anaguma (badger hole) is the castle where the king moves into the corner square itself, under the advanced edge lance, walled in by a silver, a gold, and the knight. With no empty square adjacent to the king, it is the hardest standard castle to mate.
Why is the Anaguma so strong?
Two reasons: the king cannot be checked by drops, because every adjacent square is occupied, and it stands as far as possible from the fighting. Its owner can therefore trade pieces and attack with unusual freedom, since captured material rarely converts into checks against a buried king.
What are the weaknesses of the Anaguma?
It is the slowest standard castle to build, giving the opponent free rein in the opening, and the corner offers zero escape routes once the wall cracks. Attackers target it with edge pawn breaks around 9e and by squeezing the position from a distance rather than checking.
Who should play the Anaguma?
Most famously Static Rook players facing Ranging Rook: the king digs in on the opposite wing from the enemy rook and outlasts the attacking race. It suits patient players who finish what they start, since a half-dug Anaguma is worse than most completed castles.