Shogi glossary
Right Fourth-file Rook
Japanese: 右四間飛車
In shogi, the Right Fourth-file Rook (migi shikenbisha) is a Static Rook attack in which Black moves the rook from 2h to 4h, the fourth file counted from the right, and piles pieces onto that file to break through.
Static Rook attack with the rook moved to the 4th file on the right (4h).
Why it is still Static Rook
Migi means right. The rook travels only two files and stays on Black's right side, so the king still castles on the left, usually in a quick Boat castle with the king on 7h. That is why it counts as a Static Rook strategy even though the rook has moved.
The stacking idea
Black pushes the 4th-file pawn to 4f, sets the rook on 4h and brings the right silver up via 3h and 4g to 5f, so pawn, silver and rook all bear on 4e. The break starts with the pawn to 4e; if White captures, the silver recaptures with the rook standing behind it.
Counting attackers and defenders on the 4th file decides whether the break works. The attack is classically aimed at White's Fourth-file Rook, whose rook on 4b stands on the same file and whose bishop on 3c guards the 4d pawn.
FAQ
What is the difference between Right Fourth-file Rook and Fourth-file Rook?
The Fourth-file Rook is Ranging Rook: the rook goes left to 6h and the king castles right. The Right Fourth-file Rook keeps the rook on the right at 4h, castles on the left and attacks.
Why push the pawn to 4e before the silver?
A silver stepping onto 4e can be taken by White's pawn on 4d. Pushing the pawn first lets the silver recapture safely.
Related
Terms:
Lessons: Counting Attackers and Defenders · The Boat Castle and Breaking Castles
Openings: Right Fourth-file Rook
I don't do defense. Hope you brought a castle!
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