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Game guide
Tic-Tac-Toe
Tic-Tac-Toe is the classic two-player game of X and O: take turns marking squares on a 3×3 grid, and the first player to get three in a row — across, down or diagonally — wins. A match is over in a minute or two, but there's real strategy in it: set up forks to win, and spot your opponent's before they land. Play solo against the bot, or online through quick match or a playroom with a friend, without signing up.
Objective
Be the first player to get three of your marks in a row — across a row, down a column or along a diagonal.
One player is X and the other is O. You take turns placing one mark at a time, and the match ends the moment someone completes a line. If all nine squares fill up with no line of three, the match is a draw.
Draws are common. With perfect play from both sides, every match of Tic-Tac-Toe ends in a draw, so winning comes down to setting traps and not falling into your opponent's.
The Board and Marks
Tic-Tac-Toe is played on a 3×3 grid of nine squares. One player places X marks and the other places O marks, and X always moves first. In a solo match you choose your side, so pick X if you want to start; in online matches the sides are assigned for you.
Every match starts on an empty board, with X to move.
Centre, Corners and Edges
The nine squares come in three kinds. The more winning lines pass through a square, the more useful it tends to be:
- The centre is the middle square. It is part of four lines: the middle row, the middle column and both diagonals.
- The corners are the four squares at the corners of the board. Each is part of three lines: a row, a column and a diagonal.
- The edges are the four squares in the middle of each side. Each is part of only two lines: a row and a column.
There are eight winning lines in all: three rows, three columns and two diagonals.
Taking a Turn
On your turn, click or tap any empty square to place your mark there. Then it's your opponent's turn.
- You place exactly one mark per turn, and you can't pass.
- Once a square holds a mark, it's taken for the rest of the match. Marks never move and are never removed.
- Turns keep alternating until someone gets three in a row or all nine squares are full.
X places a mark in the bottom-right corner, and then it's O's turn.
Winning and Draws
The match ends the moment a player completes a line of three of their own marks — across a row, down a column or along either diagonal. No more marks can be placed after that.
Across a Row
X completes the top row and wins the match.
Down a Column
O completes the right-hand column and wins, even though X also had two in a row — always take your own win before blocking.
Along a Diagonal
Both diagonals count, and both run through the centre.
X completes the diagonal from the top-left corner to the bottom-right corner and wins.
Draws
If all nine squares are filled and nobody has three in a row, the match is a draw. X always places the ninth and last mark, so if that mark completes a line, X wins instead.
The board is full and there is no line of three anywhere, so this match is a draw.
Opening Moves
Perfect play always ends in a draw, so the opening isn't about winning outright. As X, it's about giving your opponent chances to go wrong; as O, it's about not taking the bait.
X's First Move
- The centre is a strong, simple start. It is part of four lines, and O has to answer with a corner.
- A corner is just as strong and leaves O almost no margin for error: of O's eight possible replies, only the centre is safe.
- An edge is the weakest start. It still draws with correct play, but it is part of only two lines, so X has fewer ways to build threats.
O's First Reply
O's first move decides whether O can hold the draw:
- Against the centre, take a corner. Any corner will do. An edge reply loses: X takes a corner next to O's mark to threaten a diagonal, O is forced to block in the opposite corner, and X's next move makes two threats at once.
- Against a corner, take the centre. Every other reply loses — even the opposite corner, which looks safe. The next section shows how X punishes an edge reply.
- Against an edge, take the centre. It is the simplest safe reply.
X has opened in the centre, so O should answer in one of the four ringed corners.
Forks and Blocking
A threat is two of your marks in a line with the third square still empty. Almost every decision in Tic-Tac-Toe is about threats: making them, blocking them and doubling them up.
What to Check Every Turn
Go through this list in order and play the first move that fits:
- Win. If you have a threat, complete the line.
- Block. If your opponent has a threat, take the empty square in their line.
- Fork. If a move would give you two threats at once, play it.
- Stop a fork. If your opponent could fork on their next move, take that square — or make a threat of your own that forces them to block somewhere harmless.
- Otherwise, take the centre if it's free, then a corner, then an edge.
Blocking
A block stops your opponent's line, and the best blocks start a line of your own at the same time.
X threatens to complete the diagonal through the centre, so O blocks in the bottom-left corner — which also gives O a threat down the left column.
Forks
A fork is a move that creates two threats at once. Your opponent can block only one of them, so you complete the other on your next turn. Against an opponent who always blocks, a fork is the only way to win.
Forks are built with forcing moves: make a threat, let your opponent block where you want them to, then make two threats with your next move. Here is how X punishes O for answering a corner opening on an edge:
- X opens in the top-left corner, and O replies in the middle of the top row, right next to it.
- X takes the centre, threatening the diagonal, so O must block in the bottom-right corner.
- X plays the middle of the left column, threatening both the middle row and the left column.
X now has two threats, at the ringed squares. O can block only one, so X wins next turn.
Stopping a Fork
The best defence is to stop a fork before it exists. Here is the classic trap: X opens in a corner, O correctly takes the centre, and X takes the opposite corner. X now threatens to fork from either of the two empty corners, and O can't cover both.
O's answer is to attack. A move on an edge makes a threat that X has to block, and X's block makes at most one threat — so O can keep blocking all the way to a draw. A corner looks natural but loses: it makes a threat too, but X blocks it on the last free corner, and that block creates two threats at once.
X holds opposite corners, so O must play one of the ringed edge squares — a corner here loses.
Frequently Asked Questions
- How do you play Tic-Tac-Toe?
- Two players take turns placing X and O in the empty squares of a 3×3 grid. X always goes first. The first player to get three of their marks in a row — horizontally, vertically or diagonally — wins the match.
- What happens if the board fills up?
- If all nine squares are filled and nobody has three in a row, the match is a draw. Draws are common: with perfect play from both sides, every game of Tic-Tac-Toe ends in a draw.
- What is the best first move in Tic-Tac-Toe?
- The centre and the corners are the strongest openings, because they sit on the most winning lines. The centre is part of four lines, each corner of three and each edge square of only two.
- How do you win at Tic-Tac-Toe?
- Against a careful opponent you cannot force a win, but you can make sure you never lose. Always block a line your opponent is about to complete, and look for a fork: a move that creates two threats at once, so your opponent can only block one of them.
- Can I play Tic-Tac-Toe online with a friend?
- Yes. Play solo against the bot, join a quick match to face another player, or create a playroom and invite a friend.
- Do I need to sign up or download anything?
- No. Tic-Tac-Toe runs free in your browser and you can play instantly as a guest. Create an account later if you want to keep your match history.