Variations
Many board games share the element of trying to be the first to get n-in-a-row: three men's morris, nine men's morris, pente, gomoku, Qubic, Connect Four, Quarto, Gobblet. Generalizing the original Tic-tac-toe game, we get the -game, played on the -dimensional cube with edge. Then, the ordinary Tic-tac-toe is the -game. The m,n,k-games are a family of generalized games based on Tic-tac-toe.
- 3-dimensional tic-tac-toe on a 3?? board, though the first player has an easy win by playing in the centre if 2 people are playing. Another variant is played on a 4?? board, though it was solved by Oren Patashnik in 1980 (the first player can force a win). A more complex variant can be played on boards utilising higher dimensional space, most commonly 4 dimensions in a 3??? board. In such games the aim is to fill up the board and get more rows of three in total than the other player or to play with 4 people and get 1 row of 3.
- In Misère tic-tac-toe the player wins if the opponent gets n in a row. A 3? game is a draw.
- Tic Tac Tactic: A new game played on a three-dimensional board. Each player takes it in turns to send their ball at least half way round the curved board until it drops down into one of the 9 indents of the 3 x 3 grid. The player wins balls by forming a row of 3, and they can, using a rubber device, change the outcome of their ball's path and bounce their ball to where they want. Each 3-in-a-row wins a ball of the player. The winner is skilful enough to have won five balls off his opponent
- In Nine board tic-tac-toe, nine Tic-tac-toe boards are themselves arranged in a 3? grid. The first player's move may go on any board; all moves afterwards are placed in the empty spaces on the board corresponding to the square of the previous move (that is, if a move were in the upper-left square of a board, the next move would take place on the upper-left board). If a player cannot move because the indicated board is full, the next move may go on any board. Victory is attained by getting 3 in a row on any board. This makes the game considerably longer and more involved than Tic-tac-toe, with a definite opening, middle game and endgame.
- Super tic-tac-toe is played like Nine board tic-tac-toe except that the game does not end when a player wins a game on one of the small boards. Instead, the position of the small board where that player won is marked on a 3? grid, and a player wins when they form 3-in-a-row on that grid
- In Tic-Tac-Chess, players play a game of chess and Tic-tac-toe simultaneously. When a player captures an opponent's piece, the player can make a play on the Tic-tac-toe board regardless if the other player has not yet made a play. The first person to get 3 Xs or Os in a row wins the game. This makes for a much more defensive game of chess.
- There is a game that is isomorphic to Tic-tac-toe, but on the surface appears completely different. Two players in turn say a number between one and nine. A particular number may not be repeated. The game is won by the player who has said three numbers whose sum is 15. Plotting these numbers on a 3? magic square shows that the game exactly corresponds with Tic-tac-toe, since three numbers will be arranged in a straight line if and only if they total 15. This can be helpful in programming computer adaptations of the game, by assigning the squares of the grid to their corresponding number on the magic square.
