Backwash squeeze

Backwash squeeze is a rare squeeze which involves squeezing an opponent which lies behind declarer's menace. It was first attested by famous bridge theorist G?a Ottlik in an article in The Bridge World in 1974, as well as in his famous book Adventures in Card Play, co-authored with Hugh Kelsey.

By nature, backwash squeeze is a non-material trump squeeze without the count. It occurs when the declarer (or dummy) has high trump(s) but must not draw opponent's remaining trump(s). Instead, he ruffs a card high, and the opponent playing after, still having trump(s), must choose to under-ruff or give up one of menaces, either in form of a direct trick or an exit card, allowing later endplay. Since the squeeze is without the count, the squeezed defender will be allowed to take a later trick.

Example

		♠	KJ
		♥	32
		♦	A5
		♣	-
♠	854	N W         E S		♠	-
♥	-			♥	Q
♦	KJ			♦	10942
♣	5			♣	J
		♠	A7
		♥	-
		♦	Q83
		♣	9

Spades are trumps, and South needs five of six remaining tricks, the last trick having been taken by dummy. The material for those is theoretically there by means of ♦A and crossruffing, but West's ♠8 is in the way, as he can overruff declarer's ♠7 if he tries to ruff hearts. However, West also protects diamonds, and can be thrown-in with that trump if the correct position is set up. The declarer now ruffs a heart with trump Ace (establishing the suit), and West is backwash-squeezed. As he must not unguard diamonds, and under-ruffing will allow the declarer to draw trumps with dummy's KJ, he discards a club?his exit card. Now, the declarer draws trumps and plays now high heart from dummy; when West overrufs, he has only diamonds left and must give up a trick in the suit.