Regular tic tac toe has a ceiling. Once you know the strategy, every game against someone equally experienced ends in a draw. Always. The game is solved and there is nothing left to discover.

The variations below each change one thing. Sometimes one rule change is all it takes to turn a solved game into something genuinely interesting again.

1. Terni Lapilli — the Roman original

The oldest variation on this list by about 2,000 years. Terni Lapilli is the ancient Roman game that modern tic tac toe evolved from, played on the same 3x3 grid but with one crucial difference: each player only has three pieces and slides them around the board rather than placing new ones.

Once all six pieces are down, no new marks are ever added. Players just keep sliding until someone gets three in a row. The board never fills up, which means there is no stalemate. The game can swing completely in a few moves, and the strategy is genuinely different from the placing phase.

Archaeologists have found the grid scratched into stone all over the Roman Empire, including the steps of the Colosseum. We wrote a full rules guide if you want the details, and you can play it free here.

2. Ultimate Tic Tac Toe — nine boards in one

Take a 3x3 grid and put a complete tic tac toe board in each cell. You now have nine small boards arranged inside one large one. Win a small board and you claim that cell on the large grid. Win three cells in a row on the large grid and you win.

The twist: wherever you play within a small board determines which small board your opponent must play in next. Play the centre cell of any small board and your opponent goes to the centre board. Play the top-right cell and they go to the top-right board.

This single rule means every move has two consequences simultaneously, what happens locally in the small board and where you are sending your opponent. It is the most strategically deep variation on this list and has not been fully solved. We have a full rules and strategy guide and you can play it here.

3. 4x4 Tic Tac Toe — bigger board, four in a row

Same rules as regular tic tac toe but on a 4x4 grid. You need four in a row to win rather than three. The board is 16 squares instead of 9.

This sounds like a minor change. It is not. The increased board size means the game is no longer solved in the same trivial way as the 3x3 version. There are significantly more possible positions, more ways to threaten simultaneously, and much more room to manoeuvre before the board gets crowded. Corner control and centre control both matter more, and the fork setups that define 3x3 strategy evolve into something considerably more complex.

4x4 is the natural next step for anyone who has mastered regular tic tac toe and wants the game to feel competitive again.

4. 3D Tic Tac Toe (Qubic) — four in a row in any direction

Played on a 4x4x4 cube with 64 cells. Players take turns placing their markers and the first to get four in a row wins. The winning line can be horizontal, vertical, diagonal within a single layer, or diagonal across multiple layers, which produces 76 possible winning lines compared to 8 in regular tic tac toe.

Parker Brothers marketed a physical version called Qubic from 1964. The game was solved by Oren Patashnik in 1980, who proved the first player can always force a win with perfect play. But the game tree is large enough that playing optimally from memory is not realistic for most humans, which means in practice it plays like an unsolved game.

The main challenge of 3D tic tac toe is visualising the diagonal lines that pass through multiple layers. Most players miss them entirely until they have lost to one several times.

5. Misère Tic Tac Toe — the goal is reversed

Exactly the same as regular tic tac toe with one change: getting three in a row means you lose. Both players are trying to force the other into completing a line.

This sounds simple but it completely rearranges the strategy. The centre square, normally the strongest opening, becomes a liability because it sits on four winning lines and is therefore dangerous to occupy. Corners become threatening to your opponent rather than useful to you. The whole game inverts.

Misère on a 3x3 board is also solved. The first player can force a draw with correct play, meaning neither player is forced into completing a line. But the correct strategy is counterintuitive enough that most players will not find it naturally, which keeps the game genuinely competitive in practice.

6. Notakto — both players use X

Both players place X on every turn. There is no O. The player who completes three X's in a row loses.

It is typically played across multiple boards simultaneously. On your turn you can play on any board that is not yet complete. Once a board has three in a row it is dead and neither player can use it. The player who completes the last board loses.

Notakto is a misère game, a combinatorial game, and an impartial game all at once, which makes it interesting to mathematicians as well as players. The strategy involves deliberately forcing your opponent into being the one who has to play on the most dangerous boards. It is considerably harder than it looks from the description.

7. Wild Tic Tac Toe — choose your symbol each turn

On each turn you can place either X or O in any empty cell, regardless of which player you are. The first player to complete three of the same symbol in a row, whether X or O, wins.

The freedom to choose your symbol each turn makes the game significantly more complex than it appears. You can contribute to your opponent's potential winning line while simultaneously blocking your own. You can set up a situation where either X or O completing a line next turn means you win. Defensive play looks completely different because you cannot simply avoid your own symbol.

Wild tic tac toe on a 3x3 board has been solved. The first player can always force a win or draw. But the solution is non-obvious enough that it plays as a genuine game between most human opponents.

The pattern across all of them

Every variation on this list takes a game that is fully solved and makes it interesting again by changing one rule. The board gets bigger. The pieces slide. The goal inverts. The symbols become shared.

Regular tic tac toe is the purest version but not the deepest one. Once you have hit the ceiling, any of the above is worth trying. Terni Lapilli and Ultimate Tic Tac Toe are the two you can play free on this site if you want to start somewhere. If you want to try something completely different that still scratches the same strategic itch, Battleship uses the same hidden-information, two-player format but replaces the grid with a naval hunt across a 10×10 board.

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