Bishop Exchange Fourth File Rook

Bishop Exchange 4th Rook

☖ pieces in hand: –

9	8	7	6	5	4	3	2	1
香	桂		金		金	銀	桂	香	1
	飛		銀		王		馬		2
歩		歩	歩	歩	歩		歩	歩	3
	歩					歩			4
									5
		歩							6
歩	歩		歩	歩	歩	歩	歩	歩	7
			飛			玉			8
香	桂	銀	金		金	銀	桂	香	9

☗ pieces in hand: 角

In shogi, Bishop Exchange Fourth File Rook (角交換四間飛車 kaku kōkan shikenbisha) or Open Bishop Diagonal Fourth File Rook (角道オープン四間飛車 kaku michi ōpen shikenbisha) is a Fourth File Rook (Ranging Rook) opening in which the player's bishop diagonal remains open allowing for a bishop exchange to occur early in the opening.

This contrasts with the defensive so-called normal or standard Fourth File Rook that keeps the bishop diagonal closed until the player is ready for a counterattack so that they may avoid rough and tumble battles initiated by their opponent. (See: Types of Ranging Rook.)

Development

Bishop Exchange Fourth Rook

☖ pieces in hand: –

9	8	7	6	5	4	3	2	1
香	桂	銀	金	王	金	銀	桂	香	1
	飛						角		2
歩	歩	歩	歩	歩	歩		歩	歩	3
						歩			4
									5
		歩							6
歩	歩		歩	歩	歩	歩	歩	歩	7
	角						飛		8
香	桂	銀	金	玉	金	銀	桂	香	9

☗ pieces in hand: –

Bishop Exchange Fourth Rook

☖ pieces in hand: –

9	8	7	6	5	4	3	2	1
香	桂	銀	金	王	金	銀	桂	香	1
	飛						角		2
歩	歩	歩	歩	歩	歩		歩	歩	3
						歩			4
									5
		歩							6
歩	歩		歩	歩	歩	歩	歩	歩	7
	角		飛						8
香	桂	銀	金	玉	金	銀	桂	香	9

☗ pieces in hand: –

1. P-7f P-3d. The most common first two moves in shogi: bishop diagonals are opened.

2. R-6h. Black swings their rook to the sixth file on their second turn. This is the characteristic of Bishop Exchange Fourth File Rook.

Traditional Fourth File Rook Instead would have closed their bishop diagonal (2. P-6f) in order to prevent White from trading bishops at an inopportune time.

Bishop Exchange Fourth Rook

☖ pieces in hand: –