relation tomove parameters

A tomove parameter is a type of relation parameter that checks whether the side to move is the same in the source and the target.

A tomove parameter is either

(tomove match)
or
(tomove mismatch)
The target matches source according to the first, match version if the side to move is the same in the target and the source. The target matches the source according to the second, mismatch version if the side to move is different in the target and the source.

To recap: When a relation filter is evaluated at a particular position, that position is called the source or source position. Every other position in the game successively becomes the target or target position. For the relation filter to match at a target, each of its relation parameters must also match that target.