In the game of chess, there's a particular interaction between the king and another piece that causes them to switch positions
I've tried that, but (during my attempts so far) castling didn't trigger.
Oh? Are you sure you went to the bottom left tile of the chess board as a rook?
got it to trigger this time, guess there was a glitch during initial loading last time (it's rare for this to happen and not be noticeable)