A position in which checkmate is forced (obligatory) I am looking for a position in which all possible moves are checkmate. This means, that if the player does not want to checkmate the opponent, because for example he feels sorry for him, even in that case he is forced to checkmate him. He cannot avoid it. Can you tell me an example? White or black does not matter.

Also, I feel this can be done only if there is a very small number of possible moves. For example 1 or 2.
I just remembered a class of chess problem; see item 267 of Tim Krabbé's Open Chess Diary (his whole site is highly recommended):

[Title "White mates in 7, Noam Elkies, 2004."]
[FEN "KBk5/P1P4p/2Pp3P/P6p/2p3rP/2P3pB/6P1/8 w KQkq - 0 1"]


Spoiler: White has some choices here, he can choose different move orders. But it's always checkmate on move 7, no matter what.