In-between moves
“The moves that interrupt an expected or apparently forced tactical sequence by “slipping in”, are called intermediate or in-between moves. They can disturb or completely refute a combination, but sometimes intermediate moves are integral part of the attacking procedure.” - paraphrasing Vladimir Vukovic’s brilliant book “The Art of Chess Sacrifice”.
Intermediate moves are some of the most beautiful occurrences on the chess board. Vukovic also notes that this kind of obstacle is the main fear for every devoted attacker.

In this position, White naively trades the Bishops…
1. Bxb6?
But Black is not obliged to take that back. Instead, his reply carries much stronger threat…
