Fourth File Rook.

Ranging rook · castles into Mino · 四間飛車 shikenbisha

The idea

The most played opening among amateurs in Japan, and the one most teachers recommend first, because it is a system: you make the same dozen moves almost regardless of what the opponent does, and every one of them has a reason.

The rook swings from its home file to the file in front of the left gold (the fourth file counting from the left, hence the name), the king walks right into a Mino castle, and then you wait. A static rook opponent has to attack a solid position; when they do, you counter along the file your rook is already sitting on.

How it goes together

The plan once you are set up

• Do not attack first. Finish the castle, then improve: silver to 5f or 4g, the knight to 7g when the moment comes.
• When the static rook player attacks down the 8th file or with a silver on the 3rd, answer on the 6th: push the pawn to 6e, exchange, and let the rook and bishop come alive. This is sabaki, getting the pieces out with tempo.
• Trade the bishops when it helps you and not before. The 6f pawn is there so the choice is yours.
• In the endgame the Mino’s side walls are strong. Let the opponent come at your king from the front and use the time to attack theirs.

What to watch for

• A knight landing on 3f or a pawn on 2f is aimed at the head of your castle. Meet it early.
• The Climbing Silver against your left side: keep the 6g silver and the 7g bishop coordinated and do not let the silver sit on 7e.
• Anaguma. Against a king buried in the corner, waiting no longer works; you have to make something happen on the sixth file before they finish.

What it is played against

A static rook: the rook stays on the right and the king castles on the left, in a boat castle, a Left Mino or an Anaguma.

With an Anaguma instead of a Mino

Fourth File Rook Anaguma (四間飛車穴熊)

The Fourth File Rook can castle in an Anaguma instead of the Mino. The first moves are the same, the rook to 6h and the king to 4h, 3h and 2h; then the lance steps up to 1h, the king drops into the corner on 1i, the silver closes the hole on 2h and both golds come to the third file.

It costs several more moves than a Mino, and in return the king is much harder to reach. ja.wikipedia, summarising Hirose Akira’s books, gives the advice: play low and trade pieces, so that the distant king tells; keep the left silver at home until the bishop’s head is attacked; and against a Static Rook Anaguma, where the rook on 6h blocks the left silver’s road to the castle, bring that silver out quickly to 5f, aiming at 4e and 3d.

Hirose played it often and developed much of its theory, and ja.wikipedia’s 2019 popularity ranking puts it 49th. The board is the Anaguma page’s build, with the rook on 6h.