In chess, zwischenzug (German for "intermediate move") is a common tactic that occurs in almost every game. Zwischenzug is where Player1 threatens Player2, and instead of Player2 countering the direct threat from Player1 (which Player1 expects) Player2 plays a move which poses an even more serious threat to Player1. Player1 must then counter the threat from Player2, which will ideally change the entire situation to Player2īs advantage. Such moves are also called intermezzos.
Borisenkov-Mezenev (diagram, Black to play), continued 1...f2, threatening to queen, which White countered with 2.Rg8, intending 3.Rf8+. But White resigned after the zwischenzug 2...Bb1! which allows Black to queen (3.Kxb1 f1=Q+ or 3.Rf8+ Bf5).
These moves are given in algebraic chess notation.