Online Tic-Tac-Toe for two players

Two names, nine squares: how a game starts

For Tic-Tac-Toe you need two players and nothing else. On a shared phone, type in both names and tap “Start game”: there are no settings to adjust, no timer and no grids of different sizes. Chance takes care of the rest.

• The app draws lots for who plays ✕ and who plays ◯.
• A separate draw decides who moves first: it is not necessarily ✕, so keep an eye on the banner.
• At the top you see both names with their symbol; underneath, a line tells you whose turn it is.

The rules as the app applies them

The rules are the classic noughts and crosses ones, but a few practical details are worth knowing in advance:

• There are eight winning lines: the three rows, the three columns and the two diagonals.
• You cannot tap a square that is already taken, and a move once made cannot be undone: no second thoughts, just as on paper.
• When someone lines up three symbols, the three squares light up and the winner’s name appears. If the grid fills up with no line of three, the game ends in a Tie!.
• There is no time limit per move: you can think for as long as you like.
• The first move alternates. In a room, every time you tap “Play again” the player who moved second last time opens; on a shared phone, if you restart with the same two names, the app avoids letting the previous opener start again.

An annotated game: Jack against Grandma Pat

To follow the moves, number the squares like a phone keypad: 1, 2, 3 along the top row, 4, 5, 6 in the middle, 7, 8, 9 at the bottom. The draw gives ✕ to Jack, who moves first; Grandma Pat has ◯.

1. Jack opens in corner 1.
2. Grandma Pat replies on edge 2, right next to him. It looks like a cautious move, but against a corner opening the only safe reply is the centre.
3. Jack takes the centre, 5, and threatens the 1-5-9 diagonal.
4. Grandma Pat is forced to block at 9.
5. Jack plays 4 and creates two threats at once: the 1-4-7 column and the 4-5-6 row. This is a fork.
6. Grandma Pat can only close one of them. Jack completes the other and wins.

In the rematch Grandma Pat opens, and she has learnt her lesson: she takes the centre. Jack replies in a corner, as he should, and from there both block every threat until the game ends in a tie. Between two careful players, that is how Tic-Tac-Toe usually goes.

How to win at Tic-Tac-Toe (and how not to lose)

An honest disclaimer: if both players make no mistakes, every game is a draw. Winning means taking advantage of your opponent’s slip, and not losing means not making one yourself. On every move, check these priorities in order:

1. If you can complete a line, do it.
2. If your opponent threatens a line, block it.
3. If you can create two threats in one move, the fork, create it.
4. If your opponent is about to create a fork, stop it, even if that means forcing them to defend against a threat of your own.
5. Take the centre if it is free.
6. Otherwise choose the corner opposite one of your opponent’s, then any free corner, and only as a last resort an edge.

When you open

The corner is the opening that sets the most traps: the only reply that does not lose is the centre, while an edge, an adjacent corner or the opposite corner all allow a forced win. The centre is also a good start: here your opponent has to answer in a corner, because an edge loses. Opening on an edge is the least dangerous for your opponent.

When your opponent opens

Answer a corner with the centre, and the centre with a corner. Watch out for two mirror-image situations: if they hold two opposite corners and you have the centre (✕ on 1 and 9, ◯ on 5), your next move must go on an edge, because a corner hands them a fork. If instead they hold the centre and the corner opposite yours (✕ on 5 and 9, ◯ on 1), you must take a corner: an edge loses.

On one phone, or each on your own

On a shared phone you pass it across after every move, or leave it in the middle of the table. It works without a connection. Each game stands alone: at the end you go back to the group screen and start again, and the symbols are drawn afresh. If you want to keep a long series going, keep score on a piece of paper or play in a room.

In a room one player creates it, the other joins with the code or the QR code and the host starts the game: here too there is nothing to set. This is what changes:

• Each of you taps the grid on your own phone. The server only accepts a move from the player whose turn it is and on a free square, so there is never any doubt about who played what.
• At the end of the game the host chooses Play again or Back to lobby. With Play again the symbols stay the same, the series score carries on (each player’s wins and the draws) and the first move passes to the other player.
• If one of you loses the connection for a moment, or goes back to the lobby mid-game, the grid freezes and picks up again when they return.
• If instead they leave the room for good during a game, the other player wins by forfeit, with an extra point in the series. Left alone, they go back to the lobby and wait for a new challenger.

Who to play it with

Tic-Tac-Toe takes ten seconds to explain and a minute to play, so it is perfect for children who are learning to take turns and for grandparents who want to take on the grandchildren. It is also a good first exercise in reasoning: showing a child a fork, and then how to avoid one, teaches them to think one move ahead.

Among adults it works as a coffee-break game, something for the queue at the post office or the wait for your table at a restaurant, perhaps as a “best of five” series you agree on between you. For a longer, chattier two-player challenge, try Duel; there are more ideas in our guide to games for two people.