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.

Initial moves

Bishop Exchange up to move 2 △ pieces in hand: – 9 8 7 6 5 4 3 2 1   香 桂 銀 金 王 金 銀 桂 香 a   飛           角   b 歩 歩 歩 歩 歩 歩 歩 歩 c   歩               d                   e     歩             f 歩 歩 歩 歩 歩 歩 歩 歩 g   角           飛   h 香 桂 銀 金 玉 金 銀 桂 香 i ▲ pieces in hand: –

Bishop Exchange up to move 3 △ pieces in hand: – 9 8 7 6 5 4 3 2 1   香 桂 銀 金 王 金 銀 桂 香 a   飛           角   b 歩   歩 歩 歩 歩 歩 歩 歩 c   歩               d                   e     歩         歩   f 歩 歩   歩 歩 歩 歩 歩 g   角           飛   h 香 桂 銀 金 玉 金 銀 桂 香 i ▲ pieces in hand: –

1. P-7f. Black (先手) chooses the flexible option of activating their bishop.

1. ... P-2d. 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-3d) instead of 1. ... P-2d, then a Bishop Exchange opening would no longer be possible since Bishop Exchange openings have Black's bishop positioned on 7g followed by their left silver positioned on the same 7g. If White's bishop diagonal is open before the Black's bishop has moved to 7g, then Black will not be able to position their silver on 7g.

2. P-2f. 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.

Bishop Exchange
up to move 4

△ pieces in hand: –

9	8	7	6	5	4	3	2	1
香	桂	銀	金	王	金	銀	桂	香	a
	飛						角		b
歩		歩	歩	歩	歩	歩	歩	歩	c
									d
	歩								e
		歩					歩		f
歩	歩		歩	歩	歩	歩		歩	g
	角						飛		h
香	桂	銀	金	玉	金	銀	桂	香	i

▲ pieces in hand: –

2. ... P-8e. After the third move by Black, White has a choice between advancing their rook pawn further (2. ... P-8e) or defending the head of their bishop with a gold (金) (2. G-3b) 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-8e, 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-3b) is somewhat more flexible as the opening at this point is still ambiguous between Bishop Exchange and Side Pawn Capture.

Classic vs modern

After White's rook pawn (2. ... P-8e), Black now has two options. The older option found in Classic Bishop Exchange games was to advance Black's rook pawn (3. P-2e) 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-2e option is delayed. Instead, Black protects the eighth file with their bishop (3. B-7g).

Nonetheless, although disfavored and currently not as popular, a few professional players have played these positions 2015–2017.^[1]

Modern delayed rook pawn

Bishop Exchange
up to move 5

△ pieces in hand: –

9	8	7	6	5	4	3	2	1
香	桂	銀	金	王	金	銀	桂	香	a
	飛						角		b
歩		歩	歩	歩	歩	歩	歩	歩	c
									d
	歩								e
		歩					歩		f
歩	歩	角	歩	歩	歩	歩		歩	g
							飛		h
香	桂	銀	金	玉	金	銀	桂	香	i

▲ pieces in hand: –

3. B-7g. In modern Bishop Exchange openings, Black moves their bishop to the 7g square in order to prevent White from exchanging pawns on the eighth file instead of P-2e. This delay of advancing their rook pawn is known as 飛車先保留 (hishasaki ryūgata) in Japanese.^{[lower-alpha 1]}

Bishop Exchange up to move 6 △ pieces in hand: – 9 8 7 6 5 4 3 2 1   香 桂 銀 金 王 金 銀 桂 香 a   飛           角   b 歩   歩 歩 歩 歩 歩 歩 c             歩     d   歩               e     歩         歩   f 歩 歩 角 歩 歩 歩 歩   歩 g               飛   h 香 桂 銀 金 玉 金 銀 桂 香 i ▲ pieces in hand: –

Bishop Exchange up to move 7 △ pieces in hand: – 9 8 7 6 5 4 3 2 1   香 桂 銀 金 王 金 銀 桂 香 a   飛           角   b 歩   歩 歩 歩 歩   歩 歩 c             歩     d   歩               e     歩         歩   f 歩 歩 角 歩 歩 歩 歩   歩 g   銀           飛   h 香 桂 金 玉 金 銀 桂 香 i ▲ pieces in hand: –

3. ... P-3d. White opens their bishop diagonal attacking Black's bishop on 7g, which is a vulnerable position since Black's bishop diagonal is also open.

4. S-8h. Black moves their left silver to defend the bishop. If the bishop is captured, then the silver can move to 7g and still keep White from exchanging pawns on the eighth file. This is the quintessential position of the Bishop Exchange opening.

Black's bishop positioned on 7g is only defended by their left knight (before moving the silver). If White were to capture the bishop now (4. ... Bx7g+), then Black's knight would be forced to capture (5. Nx7g). This would leave the eighth file unprotected from White's rook pawn attack. Therefore, defending the bishop with the silver is important for defense.

Classic Bishop Exchange

Classic Bishop Exchange
up to move 5

△ pieces in hand: –

9	8	7	6	5	4	3	2	1
香	桂	銀	金	王	金	銀	桂	香	a
	飛						角		b
歩		歩	歩	歩	歩	歩	歩	歩	c
									d
	歩						歩		e
		歩							f
歩	歩		歩	歩	歩	歩		歩	g
	角						飛		h
香	桂	銀	金	玉	金	銀	桂	香	i

▲ pieces in hand: –

3. P-2e. In Classic Bishop Exchange openings, the natural move after White's P-8e was to likewise advance Black's rook pawn. Since White must defend their bishop head from this threat, Black need not immediately protect their eighth file with B-7g and could instead make 3. P-2e. However, the rook pawn push at this early juncture is now becoming disfavored by professional shogi players.

Classic Bishop Exchange
up to move 5

△ pieces in hand: –

9	8	7	6	5	4	3	2	1
香	桂	銀	金	王		銀	桂	香	a
	飛					金	角		b
歩		歩	歩	歩	歩	歩	歩	歩	c
									d
	歩						歩		e
		歩							f
歩	歩		歩	歩	歩	歩		歩	g
	角						飛		h
香	桂	銀	金	玉	金	銀	桂	香	i

▲ pieces in hand: –

3. ... G-3b. Since White's bishop diagonal is closed, White must protect their bishop head (the 2c square) from Black's second file pawn attack by moving their gold to the third file.

If White failed to protect 2c, then after a pawn exchange, Black can drop their pawn on 2c capturing White's bishop in a later move. (Cf. the similar case: Double Wing Attack § Blunder: White's failure to defend bishop.)

Variations

After the initial opening, the Bishop Exchange opening has several possible variations that follow:

• Reclining Silver
• Climbing Silver
• Rushing Silver

Each of these use a different right silver strategy

There are also other variations that use different opening move sequences:

• Tempo Loss
• Wrong Diagonal

Other variations:

• Tomioka Bishop Exchange (富岡流 tomioka-ryuu)

See also

• Bishop Exchange Reclining Silver
• Bishop Exchange Climbing Silver
• Bishop Exchange Rushing Silver
• Tempo Loss Bishop Exchange
• Wrong Diagonal Bishop
• Static Rook

Notes

Bibliography

• Fairbairn, John (1986). Shogi for beginners (2nd ed.). Ishi Press. ISBN 978-4-8718-720-10. 
• Hosking, Tony (1997). The art of shogi. The Shogi Foundation. ISBN 978-0-95310-890-9. 
• Kitao, Madoka (2011). Joseki at a glance. Translated by Kawasaki, Tomohide. Nekomado. ISBN 978-4-9052-2501-0. 

References

External links

• HIDETCHI's YouTube videos:
  • Bishop Exchange #1
  • Bishop Exchange #2
  • Bishop Exchange #3
• Yamajunn's Basic Shogi Opening:
  • Classical Kakugawari Opening
  • Kakugawari
• Yamajunn's Shogi Opening Traps:
  • Classical Kakugawari Opening Part 1
  • Classical Kakugawari Opening Part 2
  • Classical Kakugawari Opening Part 3
• Yet Another Shogi Site: Bishop Exchange: Basics
• Shogi in English: Bishop Exchange