Double Fortress

The Double Fortress (相矢倉 or 相櫓 aiyagura) is a shogi opening in which both players construct Fortress formations.

Double Fortress games are the most common type of Fortress games found at all levels of play.

Earlier josekis for Fortress in the Edo period (usually spelled 櫓 at that time) were very different from the current josekis.

In one variation, White delays pushing their rook pawn (whereas Black delays the rook pawn push in the modern era) and there is an early bishop trade before both players' kings are moved into their castles.

In the 1947 Meijin tournament, Masao Tsukada and Yoshio Kimura played an early example of the typical 3. S-77 type of Fortress with 1.P-76 P-84 development found in modern shogi.^[2]

This section needs expansion. You can help by adding to it. (June 2016)

This section needs expansion. You can help by adding to it. (May 2016)

Blocking White's bishop with a silver (and also defending the eighth file from a possible attack) is an older Fortress joseki, which typically also includes advancing Black's rook pawn.

The more recent joseki advances Black's pawn on the sixth file instead. (See above.)

Classic Fortress 24-Move Set (旧矢倉24手組 kyū yagura nijū-tegumi)

Compared to the New Fortress 24-Move Set, note that the Classic Fortress 24-Move Set is (a) symmetrical where both sides have the same formation and (b) that only Black's formation differs (White's formation is the same in both the old and new josekis.)

This section needs expansion. You can help by adding to it. (August 2016)

Right Gold To 67 (6七金右 roku-nana kin migi)

Spearing the Sparrow (雀刺し suzume-zashi)

This section needs expansion. You can help by adding to it. (May 2016)

At move 6, White also has an option to play Climbing Silver by advancing their rook pawn to rank 5. (See: White Climbing Silver.)

This section needs expansion. You can help by adding to it. (August 2016)

New Fortress 24-Move Set (新矢倉24手組 shin yagura nijū-tegumi)

This section needs expansion. You can help by adding to it. (May 2016)

Quick Fortress castling

This section needs expansion. You can help by adding to it. (May 2016)

After the 24-move set of the Fortress opening, one major branch in the Fortress strategies is the Silver-37 set of variations. Many variations are under this parent variation.