That's insane! How do you define a win, if it's 1 win from a multiverse of losses?
They do that you cannot go forwards in time until you resolve all the branches of the past, and that a checkmate on any timeline ends the match
The goal instead becomes "can I make them so disorientated by the branching paths that they don't notice I've checkmate until it's too late?" whilst simultaneously keeping track of your own many branches so they don't do the same to you
It's not actually too bad. Any checkmate wins the whole game. It just gets weird. The king can flee to another board, or you can checkmate into the past.
Where's the title text exu? Where is it, huh? You gonna hand over that xkcd title text?
(It's "Luckily, the range is limited by the fact that the square boundary lines follow great circles.")
Unfortunately doesn't seem to work with the image direct link. Thanks for providing it!

Edit: It does not. Bummer.
I mean, you already move pieces across boards in bughouse chess.
https://store.steampowered.com/app/1349230
5D chess, with multiverse time travel.
Not quite the same, but in a similar vein.
That's insane! How do you define a win, if it's 1 win from a multiverse of losses?
They do that you cannot go forwards in time until you resolve all the branches of the past, and that a checkmate on any timeline ends the match
The goal instead becomes "can I make them so disorientated by the branching paths that they don't notice I've checkmate until it's too late?" whilst simultaneously keeping track of your own many branches so they don't do the same to you
It's not actually too bad. Any checkmate wins the whole game. It just gets weird. The king can flee to another board, or you can checkmate into the past.