Goal: trap the rival king. Gold is the light court and always moves first; Emerald is the dark court.
Tap: tap one of your figures, then a glowing square. Tap it again to let go.
Pawns: advance one or two squares at any time, as long as the path is clear, and capture one or two squares diagonally. A two-square capture needs a clear path and a rival figure on the far square.
Teleporter: the crownless queen on a- and h-file replaces the outer pawns. It teleports to any square in one move. Landing on a rival figure explodes it and the teleporter dies with it — only rival kings and queens are untouchable, and a teleporter never gives check.
Trebuchet: the wooden crane on the b- and g-files replaces the second-outer pawns. It cannot march. It hurls a boulder up to four squares along a rank, file or diagonal, smashing the first figure in its path and staying where it stands; a boulder can strike any figure, the king included.
Castling: tap the king, then two squares toward a rook. The path must be clear and neither the king's square nor the crossed square may be attacked.
En passant: a pawn may take a rival pawn that has just dashed two squares past it. The chance vanishes after one move.
Promotion: a pawn reaching the far rank becomes a queen, rook, bishop, knight or a teleporter — choose the guise.
Draws: stalemate, fifty moves without a capture or pawn move, or too little material to force mate.
Spells: pawns and royalty cast beams, bishops and rooks hurl arcing magic, knights charge as spectral horses, a teleporter winks across the board, and a trebuchet looses a boulder the size of a figure. A capture burns, breaks or explodes the rival figure and leaves a scar on the square for the rest of the duel.
Endgame: when seventeen figures have fallen, the board splits with a great crack. A checkmated king topples and bursts into flame — no panel, just the ruin.
Local duel: two players share this screen. Multiplayer: open the lobby with a friend; the host is Gold, the guest Emerald, and the board turns for Emerald.