My friends and I have been playing knightmare chess in a four player variant. We were playing with the stipulation that when a player is checkmated, after his turn he removes his king from the board and his pieces change allegiance to the last player to cause checkmate.
I had caused checkmate on a player. An opponent between my turn and the checkmated player moved his bishop to cause check on the same king I had checkmated. He staked a claim to this player's pieces. I refuted his claim on the basis his bishop did not cause checkmate, only check while my peices actually did cause checkmate. Who would get the pieces?
By definition, check is a move where a peice is threatening on his opponents next turn. According to this, I argued that I caused checkmate and was entitled to his peices.