Yagura Silver-37.

Static rook, the Yagura · castles into Yagura · 矢倉３七銀 yagura san-nana gin

The idea

Silver-37 is the attacking system Black plays from the Double Yagura: the right silver goes up to 3g as soon as the 24-move opening is complete, before the king castles.

(The Yagura page ends on the same silver by another order, with both kings castled first.) ja.wikipedia calls it a main line of the Double Yagura and, citing Morishita Taku, traces it to a Yagura that Nada Renshō devised between 1965 and 1974.

From 3g the silver can go three ways: trade the 3rd-file pawn with the bishop, climb the 2nd file as a Climbing Silver, or come out to 4f beside a knight on 3g. White’s standard reply is the bishop out to 6d, aimed down the diagonal at the silver and the rook behind it, which stops the pawn to 3e for now.

Black then puts the bishop on 6h, castles, and builds the silver on 4f and the knight on 3g. In this line Black also puts the rook on 3h behind the 3rd-file pawn, then breaks with the pawn to 3e, jumps the knight to 2e, and finishes with a pawn dropped on 3c and an attack on the edge.

The whole order has one source, from 2004, which calls the position at move 46 Black’s ideal shape; ja.wikipedia says White’s later defences were built to prevent that shape and that Black has avoided it since about 2015.

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

• Play the 24-move Yagura with the rook pawn still at home, then the pawn to 3f and the silver to 3g.
• Against White’s bishop on 6d, do not push the pawn to 3e yet: move the bishop to 6h and castle the king on 8h.
• Bring the silver to 4f and the knight to 3g; push the edge pawn to 1e and move the rook to 3h.
• Break with the pawn to 3e. After White takes, jump the knight to 2e and trade silvers on 3e.
• Drop a pawn on 3c to pull the knight forward, then attack the edge: the knight in on 1c and the pawn to 1d.

What to watch for

• The pawn to 3e too early. With White’s bishop on 6d, the exchange on 3e lets White drop a pawn on 3f at the silver, which the bishop already eyes, with the rook behind it.
• The edge. Push the edge pawn to 1e before attacking; the knight on 2e can then be given up on 1c.
• The ideal shape is what White plays against. ja.wikipedia says White learned to answer it with the bishop kept on 7c and a pawn to 4e against the silver, and that from about 2015 Black often chose other plans.

What it is played against

White’s usual reply to the silver on 3g is the bishop to 6d, then its own Yagura with the king on 2b. In this line White moves the bishop on to 7c and 8d and adds the knight on 7c, which leaves Black free to build the ideal shape.

Later defences put the silver on 2d early, keep the bishop on 7c to answer the silver with a pawn to 4e, or counterattack on the edge with a pawn to 9e.