Everyone talks about the first move in tic tac toe. Take the centre. Take a corner. Never start on an edge.

But the data from 3,417 real online games played on TicToe.org says the first move is not where games are decided. The second one is.

Half the damage is done by move two

We checked every move of every online game against a perfect solver. A move counts as a mistake if the position was safe before it, and afterwards the opponent can force a win no matter what you do next.

Mistake rate by move number (3,417 online games):

The first move can never be a mistake, because every opening square leads to a draw with perfect play. The second move is a different story. In 1,599 of the 3,417 games, 46.8%, the second player's very first move already gave the opponent a forced win.

After that, mistakes get steadily rarer. By the end of the game, players almost never blunder. The danger is right at the start, when the board looks empty and harmless.

A bad reply usually decides the game

Not every forced win gets converted. Players miss chances all the time. But a bad second move still changes the outcome dramatically.

After a mistaken reply (1,599 games):

After a correct reply (1,818 games):

A correct reply makes a draw the most likely result by far. A mistaken one triples the starter's chances of winning.

Of the 1,417 games the first player won, 1,027, or 72%, followed a mistaken reply on move two. The famous first-mover advantage in tic tac toe is mostly the second player's own doing.

The corner opening is the real trap

The most popular opening in our online data is a corner, chosen in 56% of games. It also has the narrowest escape. Against a corner, there is exactly one safe reply: the centre. Every other square loses with perfect play.

61% of players answering a corner got it wrong.

How replies to a corner opening ended · 1,913 online games · first player's win rate
First player's win rate for each reply to a corner opening, from 1,913 online games on TicToe.org. Corners are mirrored onto the top-left. Only the centre is safe.

The worst reply of all is the corner right next to the opening, on the same side of the board. It was chosen 434 times and the first player went on to win 75% of those games. It feels natural, because corners are supposed to be strong. Here it is the single most expensive move in the dataset.

The centre opening is far more forgiving

If the first player opens in the centre, the second player has four safe replies: any corner. Only the edges lose.

Players handled this much better. 74% replied in a corner, and those games ended in a draw 76% of the time. The 26% who replied on an edge saw the first player win 78% of their games, the highest win rate for any opening and reply in our data.

The edge opening, chosen in only 13% of games, is the most forgiving of all. It has four safe replies: the centre, the two corners next to it, and the edge directly opposite. It is also the only opening where the second player wins a meaningful share of games, 30% after a reply in a corner. This matches what we found in our analysis of 50,008 games: the strongest-looking openings are not always the ones that win.

It gets worse the longer you play

You might expect players to learn the right reply after a few games. The data says the opposite.

Second-move mistake rate by game number within a match:

The longer two players keep playing each other, the more often the second player gets move two wrong. Rushing is not the explanation: mistaken replies and correct ones took almost exactly the same time, a median of 2.3 and 2.2 seconds. The most likely explanation is that long matches turn into fast, casual play, where the reply becomes a habit rather than a decision.

What this means if you are playing right now

Most important: If your opponent opens in a corner, take the centre. It is the only safe reply. Every other square lost far more often in our data, and the corner next to the opening was the worst of all.

If your opponent opens in the centre: take any corner. Never an edge.

If your opponent opens on an edge: the centre is safest, but the two neighbouring corners and the opposite edge are also fine.

If you are going first: open in a corner. Against a human, it gives your opponent the most ways to go wrong. 61% of them did.

These rules come straight from game theory and work against any opponent. If you want to practise them against an opponent that never makes a mistake, try Hard mode, or read how not to lose to a perfect tic tac toe AI. For the full rules of never losing, see our strategy guide.

About this data

All figures come from 3,417 completed online games between two human players on TicToe.org, played between 13 and 18 October 2026. The games were played by 420 different browsers across 289 matches. Games where the same browser controlled both sides were excluded.

A move is counted as a mistake when the position was a draw or better for the player before the move, and a forced loss after it, assuming perfect play from then on. Every move was checked against a complete tic tac toe solver. Corners and edges are grouped by their position relative to the opening square, so the board's symmetry is taken into account.

As with our other analyses, we cannot guarantee that every game comes from a unique person. Some players play many games, and a browser is not the same as a person. The patterns should be treated as observational rather than experimental.

Data collection is ongoing. This post will be updated as more games are played.

Sources