Direct Opposing Rook.

Ranging rook, played by White · castles into Mino, on White’s side · ダイレクト向かい飛車 dairekuto mukaibisha

The idea

This line is White’s. The Direct Opposing Rook keeps the bishop’s diagonal open and trades bishops itself, on 8h, on the fourth move. Older bishop-exchange ranging rooks put the rook on 4b first and moved it to 2b later, because a Black bishop dropped on 6e attacks 4c and 8c at once, and the rook on 4b guards 4c.

The Direct Opposing Rook skips that stop and saves the move, which is what “direct” means. Its answer to the bishop on 6e is a bishop of your own on 7d, across its path.

If Black promotes on 4c, the right gold comes to 5b and, shogi-rule.com says, the horse can be trapped, so Black gives it for the gold and drops a gold on 7e at your bishop; ja.wikipedia gives this as the line after the gold move.

Satō Yasumitsu tried the direct swing in his games, and it was very popular among professionals in 2013, the year Ōishi Tadashi built his results on it. The castle that comes next is a Mino, built quickly, and the line stops short of it.

How it goes together

Both sides’ moves are shown, because this opening is an agreement rather than a system: one player cannot reach it alone, so a one-sided list of moves would be a fiction.

The plan once you are set up

• After Black’s 7f and 2f, trade bishops on 8h.
• Bring the left silver to 4b and 3c, so Black’s pawn to 2d does not break through.
• Swing the rook from 8b to 2b in one move.
• If Black drops a bishop on 6e, drop yours on 7d; if Black then promotes on 4c, bring the right gold to 5b.
• Otherwise castle quickly into a Mino, then use the left silver: the pawn to 2d when it works, or the silver out to 4d and on to 5e or 3e.

What to watch for

• Which gold goes to 5b. With Black’s pawn on 2e, the left gold loses to the pawn to 2d, the exchange and a pawn dropped on 2c; the right gold is the safe one.
• Black taking on 7d instead of promoting: bishop takes bishop, your pawn takes back, and Black pushes the pawn to 7e. ja.wikipedia calls the result hard to judge.
• Guarding against the bishop drop in advance with the left gold. The Mynavi column says not to.

What it is played against

A static rook that has opened its diagonal and pushed the rook pawn to 2f. The sharp reply is the bishop drop on 6e; the quiet one, in the Mynavi column, is to castle and aim the knight at 3c with the pawn to 3f and the knight to 3g.

A later form

Tonari’s form (都成式)

Tonari Ryūma’s version, from his 2021 book, as ja.wikipedia gives it. You push the edge pawn twice, to 9e, trade bishops only on move eight, bring the silver to 3c and push the pawn to 4d, and swing the rook to 2b last. The edge pawn takes the space first.

The pawn on 4d is there for the bishop drop: after the bishop on 6e, your bishop on 7d and the promotion on 4c, there is no pawn left on 4c for the horse to win. The line has one source, with its diagram. It is a different line from the Tonari, the trap with the gold on 3a by the same player.