Ultimate Tic-Tac-Toe

• Board
• Objective
• Play

Ultimate Tic-Tac-Toe is played on the board with nine "Tic-tac-toe" boards arranged in a 3 × 3 grid. Each of the smaller 3x3 boards is called a "local board" and the larger 3x3 grid is called a "global board"

The winner of the game is the player who wins "Tic-tac-toe" on the global board, i.e. wins on three local boards on a horizontal. vertical or a diagonal row:

Os win this game

The game begins with an empty board. There are two players in the game: Xs and Os.

Xs begins by drawing "X" anywhere on the global board. The relative position of their move within the local board they made their move on defines the next local board where Os have to play their move:

Xs played at the bottom middle square on the local board.
Now Os are forced to play their move on the bottom middle local board.

In the same way the relative position of the move made by Os defines the local board where Xs are forced to make their next move and so on.

If a move is played so that it is to win a local board by the rules of normal "Tic-Tac-Toe", then the entire local board is marked as a victory for the player on the global board.

Once a local board is won by some player or it is filled completely, no more moves may be played on that local board. If a player is sent to such a local board by the previous move, then that player may play on any empty cell of any local board that is not won yet.

Game play ends when either a player wins the global board or there are no legal moves remaining, in which case the game is a draw.