Classic 3×3
The original. Play against AI (four difficulty levels) or a friend. Tracks wins and draws.
Play →Play Tic-Tac-Toe the way it was meant to be: fun.
Classic 3×3, Ultimate, 4×4, Misère, and more. Beat a clever AI or challenge a friend on the same device. Free. No signup. Works on mobile.
Pick your game mode
Ultimate Tic-Tac-Toe
Nine boards inside one. Your move decides where your opponent plays next. Endlessly deep.
Play →Misère (Reverse)
Three in a row? You lose. The classic flipped on its head. Trickier than it sounds.
Play →4×4 & 5×5
Bigger boards, more room to plan. Get four in a row to win.
Play →Learn the game
Thirteen in-depth articles on strategy, math, history, and code — for every variant on the site.
How to Never Lose
The complete classic strategy. With perfect play, a draw is the worst you can get.
Ultimate Strategy
The complete guide to the 9-boards-in-1 variant. How to read the big board.
How the AI Thinks
The minimax algorithm, explained simply. The math that makes the bot unbeatable.
Why It's Always a Draw
The math of "solved" games and the elegant strategy-stealing argument.
Build It in Python
A complete beginner tutorial. From empty file to unbeatable AI in 100 lines.
Build It in JavaScript
The same game, in the browser. The exact code that powers this site.
A 4,000-Year History
From ancient Egypt to Roman Terni Lapilli to the schoolyards of today.
All 13 Articles →
Strategy, math, history, code tutorials, and variants. Browse the full blog.