German "in-between move". An unexpected move tossed into an expected series of moves.

An in-between move. For example, instead of re-capturing, a check may be given first.

[from German, "in-between move"] An "inbetween" move, or an intermezzo, played before an expected reply. Often, but not always, this involves responding to a threat by posing an even greater threat, forcing the opponent to respond to the threat first.