Moremover

A moremover is a directmate whose limit is four White moves or more. Black still resists, and White must show that mate can be forced against every legal defense within the stated number of moves.

In the usual #n notation, n is the number of White moves. The boundary is simply length: #4, #5, and any longer directmate belong to this category. A threemover still has its own category, as does a twomover.

The extra length allows plans with more preparation, redirection, and maneuvering before mate, but it does not change the basic objective. Moremover does not simply mean a long problem: a four-move helpmate or selfmate belongs to a different type because the relationship between the two sides is different.