Bishop Exchange

In shogi, Bishop Exchange (角換わり kakugawari) is a Double Static Rook (相居飛車) opening (戦法) in which each player's bishop (角) is captured relatively early so that they keep their bishops in hand.

1. P-76. Black (先手) chooses the flexible option of activating their bishop.

1. ...P-24. White (後手) pushes their rook pawn (歩) showing their intent to play Static Rook.

Note that if White had opened their bishop diagonal (1. ...P-34) instead of 1. ...P-24, then a Bishop Exchange opening would no longer be possible since Bishop Exchange openings have Black's bishop positioned on 77 followed by their left silver positioned on the same 77. If White's bishop diagonal is open before the Black's bishop has moved to 77, then Black will not be able to position their silver on 77.

2. P-26. Black mirrors White in activating their rook (飛) with a rook pawn push. Thus, the game can now be seen as a Double Static Rook game.

2. ...P-85. After the third move by Black, White has a choice between advancing their rook pawn further (2. ...P-85) or defending the head of their bishop with a gold (金) (2. G-32) from Black's possible second file pawn attack.

The rook pawn option (shown here) is more suggestive of a Bishop Exchange opening since White is threatening to exchange eighth file pawns before Black exchanges pawns on the second file which may lead to White gaining the initiative. While, in response to White's 2. ...P-85, Black could advance their rook pawn on the second file as well, doing so is more suggestive of a Side Pawn Capture opening in professional play since modern Bishop Exchange openings generally delay a second file pawn push for later in the game. Therefore, Black's most common response to the White's rook pawn push is to move their bishop to the seventh file preventing White's pawn exchange, which leads to a Bishop Exchange opening.

The gold option (2. ..G-32) is somewhat more flexible as the opening at this point is still ambiguous between Bishop Exchange and Side Pawn Capture.

After White's rook pawn (2. ...P-85), Black now has two options. The older option found in Classic Bishop Exchange games was to advance Black's rook pawn (3. P-25) since White's bishop head is unprotected. (See § Classic Bishop Exchange below.)

However, this move has been replaced in more recent Bishop Exchange games (see § Modern Bishop Exchange (Delayed rook pawn push) below) where the P-25 option is delayed. Instead, Black protects the eighth file with their bishop (3. B-77).

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