XO Battle is free online tic-tac-toe: play the computer on Easy, Medium or Hard, or a friend on the same device. Choose X or O, flip the rules with Misère mode, switch between a flat board and a 3D glass board, and track your win streak.
How do you play XO Battle online?
- 1Choose vs Computer or vs Friend (two players sharing one device).
- 2Against the computer, pick a difficulty and whether you play X or O. X always moves first.
- 3Tap or click an empty square to place your mark.
- 4Get three of your marks in a row — across, down or diagonally — to win. A full board with no line is a draw.
- 5Use Undo to take back a move or Hint to see the strongest move for the side to play.
Controls
| Action | Desktop | Mobile |
|---|---|---|
| Place mark | Click a cell | Tap a cell |
What are the rules of XO Battle?
- –Players alternate turns, X then O.
- –Easy plays random squares; Medium takes a win when it sees one and blocks yours, otherwise plays randomly; Hard searches every possible game and cannot be beaten.
- –Misère mode reverses the goal: whoever completes three in a row loses.
- –Undo against the computer takes back both your move and its reply.
- –Wins, losses and draws are tallied, along with your current and best win streak.
What are the best tips for winning at XO Battle?
- –Take the centre when you can — it is part of four of the eight winning lines.
- –Corners beat edges: a corner sits on three lines, an edge on only two.
- –Look for forks, a move that creates two threats at once — your opponent can only block one.
- –Against Hard, play for the draw: answer a corner opening with the centre.
- –In Misère, avoid the centre early — it gives you the most ways to be forced into a line.
What is XO Battle?
Tic-tac-toe is old enough that boards resembling it have been found carved in ancient stone, and it is small enough to be solved completely: with best play from both sides, every game is a draw. XO Battle is built around that fact. The Hard computer searches the whole game tree with the minimax algorithm, so it never loses — the best result available against it is a draw, and earning one is a genuine test of spotting forks before they happen. Easy and Medium exist so the game is fun on the way there: Easy picks squares at random, while Medium will always take a winning square and block yours but otherwise plays loosely. Misère mode turns the game inside out — completing a line loses — which makes even familiar positions feel new, and the computer plays it with the same full search. You can play as X or O, take back moves, ask for a hint that shows the strongest move, and switch between the classic flat board and a real-time 3D glass board rendered with WebGL. A tally of wins, losses and draws sits beside the board along with your current and best win streak.
