The board is a 3×3 grid of medium boards. Each medium board holds a 3×3 grid of small boards, and each small board is an ordinary 3×3 game. That is 729 squares in total.
Winning. Win three cells in a line to take a small board. Win three small boards in a line to take a medium board. Win three medium boards in a line to win the game.
Where you must play. The position of your move inside its small board sets where the next player must move. Play the middle-right cell of a small board and the next player must play in the middle-right small board of that same medium board.
Free moves. If the target small board is already decided, or its medium board is decided, the next player may play anywhere legal. Those moves are marked (F) in the log.
Notation. Positions read medium.small.cell using T/M/B for top, middle and bottom and L/C/R for left, centre and right — for example MC.TL.BR.
Layouts. Empty Start Board begins on a blank grid. Random Start Position deals a scattered opening with no medium board already won.
Twiddles plays both sides. Press Next move to walk through the game one step at a time — each move is explained below the buttons.
This is the empty board. X moves first. Press Next move to watch the game one move at a time.