Whether you call it Zwischenzug (from German), Intermezzo (from Italian), an intermediate move or just an in-between move, it's all the same thing. It's a very common tactic that you need to know because it happens in almost all chess games. A Zwischenzug is when a player, instead of playing the expected move, often a recapture, plays another move that makes an immediate threat that the opponent must answer, before playing the original expected move.
In this Savielly Tartakower - Jose Raul Capablanca game from 1924, Tarakower just played Bxb8. Instead of recapturing immediately with Rxb8, can you find a better move that makes a strong threat?9...
