Second Checkmate Chess

It seems that I turned into theorem the stablest axiom of chess world.

Rules

Setup, pieces and rules are exactly as in FIDE chess but aim is changed: winner is player who delivers the second checkmate on the board. Therefore first checkmate is not the end of the game. There are two versions of scenarios after first checkmate:

• Destruction — piece that delivered mate by giving check disappears immediately, opponent can move after this;
• Teleportation — after getting mated, King teleports to any desired square (but this action costs a turn).

In both cases, the mated King has a checker added underneath it to show that a checkmate happened, and the King and checker are moved together as one piece.

But then game continues as in usual Chess. So next checkmate is win for player who does it.
If draw situation (stalemate, threefold repetition of position or insufficient checkmating material) happens at any point of the game, e. g. immediately after first checkmate, result is a draw.

Notes

First version makes attacking side to lose a piece but leaves defending side's King in uncomfortable place, while second version doesn't remove attacker's piece but lets defender to change his/her position from insanely bad to extremely good. In general you should be ready to checkmate twice!

Last revised by A. M. DeWitt.