What is TicTacToku?
TicTacToku takes the calm, deductive flow of Sudoku and drops it onto a Tic-Tac-Toe battlefield. The board is a standard 9x9 Sudoku grid, split into nine 3x3 boxes. You place digits 1 through 9 under normal Sudoku rules — no repeats in any row, column, or box — but the goal is not to solve the whole grid.
Instead, the moment your move correctly fills the last empty cell of a 3x3 box, you claim that box. Claimed boxes are marked with your symbol, X or O, exactly like a giant game of Tic-Tac-Toe laid over the puzzle. Get three of your boxes in a line and the match is yours.
How a match works
Fill cells
Place digits 1–9 using normal Sudoku logic. Illegal moves that repeat a digit in a row, column, or box are rejected.
Claim boxes
Complete all nine cells of a 3x3 box correctly and it is claimed in your color — X for player one, O for player two.
Line up three
Three claimed boxes in a row, column, or diagonal wins the match instantly — just like Tic-Tac-Toe.
Or take the majority
If all nine boxes get claimed with no line, whoever owns the most boxes wins — nine boxes never split evenly, so there is always a winner.
New here? The full rules, with examples, live in the How to Play guide.
Solve side by side
Both players get the same puzzle and solve their own private copy at the same time. You never see your opponent's digits — only the boxes they claim, tinted X or O on your board. Whoever's move completes a box first claims it on both screens. It is a real-time race: think fast, but stay correct.
Why players love it
- Short matches — a full game is minutes, not the half hour a full Sudoku takes.
- Real head-to-head tension on top of familiar, relaxing Sudoku logic.
- Play as a guest instantly, or sign in to keep your username and ranking.
- A global leaderboard and ELO rating that reward both speed and accuracy.
- Runs in any modern browser and on Android — nothing to install on the web.
- A server-authoritative backend means a fair match every time: no cheating, no rigged boards.
A game of real strategy
TicTacToku rewards more than fast fingers. Because the puzzles are solvable but not always uniquely solvable, a string of legal moves can paint a box into a corner that cannot be finished — and then you may have to yield that box to your opponent and win your line elsewhere. Knowing which boxes to chase, which to block, and which to abandon is where matches are won.
Dig into the tactics in the Strategy guide.
Frequently asked questions
Is TicTacToku free?
Yes, completely free. There is nothing to buy and no paywall. The web version has no ads at all.
Do I need to download anything?
No. The web version runs instantly in your browser. An Android app is also available if you prefer to play on your phone.
Do I need an account?
No. You can play as a guest with no sign-up. Signing in with Google is optional and only keeps your username and stats across devices.
Do I have to be good at Sudoku?
It helps, but matches are short and the goal is lining up boxes, not solving the whole grid. Beginners can win on tactics and speed.
Can I play against a friend?
Yes. TicTacToku is multiplayer — you are matched with another player, and a bot fills in when no human opponent is available so you can always play.
About
TicTacToku is built by Powered Sciences, an independent studio making small, sharp games. Questions or feedback? Email alfred.gamulo@gmail.com. Read how we handle your data in the Privacy Policy.