> I only end up with 4 dimensions I think you're right. Even if we classify classical Chess as 3D (2D board + a time axis for game states), time travel re-uses

> I only end up with 4 dimensions I think you're right. Even if we classify classical Chess as 3D (2D board + a time axis for game states), time travel re-uses that same time dimension. If you wanted to shift the complexity into ludicrous speed (this is inspired by archgoon's comment [0]), you could introduce another dimension by putting a classical chess board inside each square of the 4D board. The 4D move only succeeds if you win the game on the mini-board. Just, please, don't bring recursion into this, unless you're captain Kirk and absolutely need to nerd-snipe a rogue AI. (“They've gone to plaid!”) There's another possibility I've hinted at by calling standard Chess ‘classical’. On second thought, let’s not go to Quantum Chess. 'Tis a silly place. (I tried to imagine what a Schrödinger's king would look like. I've seen things you people wouldn't believe. Queens checked en passant from the future. I watched knigths glitter in the parallel time-line near the Hadamard Gate. All those moments will be lost in time, like tears in rain. Time to resign.) [0] https://news.ycombinator.com/item?id=24064974 https://news.ycombinator.com/item?id=24064974