Everything you need to know - assuming you already know how to play chess.

For the most part, Check, Checkmate and Stalemate work similarly to normal chess, with slight variations to accommodate three players:


Diagonal movement works as in classic chess for the most part.
When moving through the center, the player can choose which path to follow along the same tile colour.


The knight moves one square in one orthogonal direction, then two in the other - exactly as in standard chess.
Around the center of the board, this can give the knight more than the usual eight possible squares.
Castling is valid, just as in standard chess.
Select your King to see valid moves - if castling is available, select the Rook to perform it.


The current turn is shown by the turn indicators - green highlights the active player.
Turn order: White → Black → Red.


On occasion it is possible for a King to be taken in three-player chess. Consider: the White Pawn takes the Red Pawn, leaving the Red King in check by the Black Queen.
So what happens?
The Black Queen has the option to take the Red King, eliminating the Red player from the game.
Jump straight into a game and try it for yourself.