Clearance sacrifice

In chess, a clearance sacrifice is a tactical motif which involves a square on the chessboard being vacated to open up lines of attack. The tactic may also result in the substitution of a piece hindering the attack by a piece useful to the attack.

Example of clearance sacrifice

	a	b	c	d	e	f	g	h
8									8
7									7
6									6
5									5
4									4
3									3
2									2
1									1
	a	b	c	d	e	f	g	h

1.Rf8+ Rxf8 2.Qg8+ Rxg8 3.Nf7#

Example

In the diagram, the clearance sacrifice 1.Rf8+ vacates the f7 square and, after 1...Rxf8 (better than 1...Bxf8 2.Qg8#), White utilizes the battery on the a2–g8 diagonal. After 2.Qg8+ Rxg8 (only move), White has a classic smothered mate with 3.Nf7#, utilizing the f7 square vacated by the clearance sacrifice.