How to play Gomoku (Five in a Row)

Gomoku — also called Five in a Row, Gobang, or Omok — is a classic strategy game played on the intersections of a grid with two colours of stone. Here you play it in your browser against a computer opponent, with no download and no sign-up. You take the dark stone and move first; the bot answers with the light stone. The aim is simple to state and surprisingly deep to play: be the first to line up five of your own stones in an unbroken row.

The goal

Make a straight line of five or more of your stones — horizontally, vertically, or along either diagonal. The moment one side completes such a line, that side wins and the line lights up. If every cell on the board fills up and neither side has five in a row, the game is a draw, though on a full 15×15 board that is rare.

The board and the moves

The board is a 15×15 grid of cells. Players alternate turns, each placing a single stone on any empty cell. Stones never move once placed and are never captured or removed — Gomoku is purely additive, so every move is permanent. Because you move first, you hold the initiative; use it to build threats rather than scatter stones around the board.

• Tap or click any empty cell to drop your dark stone there.
• The bot replies a moment later with a light stone.
• The cell you just played is ringed so you can track the action.
• The winning five-in-a-row is highlighted as soon as it forms.
• Press N, or the new-game button, to start over at any time.

Strategy

The heart of Gomoku is the threat. An "open three" — three of your stones in a row with empty cells on both ends — forces your opponent to respond, because if you are left alone you turn it into an open four, and an open four cannot be stopped (it threatens to become five on either side). The strongest attacks chain threats together: a "double threat" creates two winning lines at once that the opponent cannot both block. Equally important is defence. Watch the bot's stones every turn and block its open threes and any four before it can complete five, or you will lose to a forced line. Strong players think a move or two ahead, balancing their own building lines against the threats they must answer. Control of the centre matters because stones there reach in all four directions, so your opening moves should cluster near the middle rather than drift to the edges.

Choosing a difficulty

Open Settings to pick a bot strength. On Easy the bot only chases its own lines and largely ignores yours, so you can win by building a single steady threat. On Medium it always completes its own five when it can and blocks your fours and open threes. On Hard it weighs your threats even more heavily and defends tenaciously, so you will need genuine double threats to break through. Your choice is remembered on this device for next time.