🧠Cerebite

How to Play Gomoku

Six short steps. Each one has a small board — try the move yourself.

🎯 The board and the stones

Gomoku is played on the intersections of a grid, usually 15×15. Black moves first, then the players alternate, one stone at a time. Stones never move once placed.

Try it: place a black stone on any intersection.

🏆 Five in a row wins

Line up five of your stones without a gap — horizontally, vertically or diagonally — and you win at once. Four is not enough.

Try it: Black has four in a row. Complete the five.

🔺 Open three and open four

Three stones in a row with both ends free is an open three. Add one more and it becomes an open four: two ways to make five, and the opponent can only block one.

Try it: turn Black's open three into an open four.

🛡️ Block threats in time

A four must be blocked at once, and an open three should be blocked before it becomes an open four. Checking the opponent's threats before every move is the most important habit in the game.

Try it: you are White. Black has a diagonal four — block it.

🚫 The double-three rule

A move that makes two open threes at once is a double-three. Under Renju and the no double-three rule, Black may not play it, because Black already has the first-move advantage. White may.

Try it: find the point where Black would make a double-three.

⚡ The four-three: a winning shape

The surest way to win is a four-three: one stone that makes a four and an open three together. The opponent must block the four, and the three then becomes an open four. It is legal for Black in every rule set.

Try it: find the move that makes a four and an open three at the same time.

Play Gomoku ▶

The whole game in one sentence

Make five in a row before your opponent does. Everything else in Gomoku — threes, fours, forbidden points — is a consequence of that single goal, which is why the game can be learned in a minute but keeps rewarding practice for years.

Because each move adds a stone and nothing is ever removed, the board only gets more crowded. Every stone you place is both an attack on your own line and a block on your opponent's, and good moves usually do both.

Reading threats: what must be answered

Why Renju forbids some moves for Black

The first player in Gomoku has a proven forced win on a 15×15 board. Renju keeps the board and the goal but forbids Black three things: a double-three, a double-four and an overline of six or more. A five always takes priority, so a move that completes exactly five is never forbidden.

A three only counts toward a double-three if it could really become an open four. If the point that would make the four is itself forbidden, the three is false and does not count. The game on this site checks this automatically and marks the forbidden points with a red cross, so you can learn the rule by seeing where it applies.

More to try

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Gomoku (Five in a Row)

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Othello (Reversi)

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How to Play Othello

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Sudoku (play & print)

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Random Name Picker

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US States Quiz

Frequently asked questions

How long does it take to learn Gomoku?
The rules take about a minute: alternate stones, five in a row wins. This six-step tutorial adds the ideas that decide real games — open threes, fours, blocking and the four-three — and takes about five minutes.
Do diagonal lines count?
Yes. Five in a row counts in all four directions: horizontal, vertical and both diagonals. Diagonal threats are the easiest to miss, so check them before every move.
Does six in a row win?
It depends on the rules. In free-style it wins. In standard Gomoku only exactly five wins, for both players. In Renju a line of six or more is forbidden for Black, while White still wins with it.
What is the difference between an open three and a closed three?
An open three has room at both ends, so one more stone makes an open four that cannot be blocked. A closed three is blocked on one side by a stone or the edge of the board, so the best it can become is an ordinary four, which the opponent can block.
Is a four-three allowed for Black in Renju?
Yes. Renju forbids double-threes, double-fours and overlines, but a four combined with an open three is legal, and it is Black's main way to win under those rules.
Where can I play after the tutorial?
The last step links to the Gomoku game on this site, where you can play the computer on three levels or a friend on the same device, with free-style, standard, no double-three or Renju rules.