How do you win at Gomoku?
The first player to make an unbroken row of five stones horizontally, vertically or diagonally wins. Black moves first, and players take turns placing one stone on any empty intersection.
Gomoku, also called Five in a Row, is known as Omok in Korea and Gobang in China. This page follows the Korean way of playing it. This site uses a 15 by 15 board, the same size used in official Renju play. A row of six or more (an overline) also counts as a win here.
What is the double three rule?
It bans a move that creates two open threes at the same time. An open three is three stones with both ends empty, which becomes an unstoppable open four on the next move.
With two open threes the opponent can block only one, so the game is basically over. That is why casual Omok in Korea usually bans the double three, and on this site the "No double three" rule applies to both Black and White. Hover over a banned point and a red cross appears. A move that completes five is always allowed, even if it is a double three.
| Rule | Banned moves |
|---|---|
| No double three (default here) | Double three (3x3) for both players |
| Free | Nothing is banned. Double threes and double fours are allowed |
| Renju (official) | Black only: 3x3, 4x4 and overlines. White has no restrictions |
Gomoku tips for beginners
- Start in the center. Stones near the edge have half as many directions to grow.
- Block every open three right away. One move late and it becomes an open four that cannot be stopped.
- Aim for a four three. A move that makes a four (which must be blocked) and an open three at once leaves your opponent able to stop only one. It is legal under the double three rule and is the most reliable way to win.
- Defend while attacking. When you have to block, pick the blocking point that also connects to your own stones.
- Watch the diagonals. They are much easier to miss than rows and columns.
On Hard, the computer looks for sequences of consecutive fours that force a win and also blocks yours. Practice building a four three on Normal first.
Controls
- Mouse: click an empty intersection to place a stone. A faint stone shows where it will go.
- Touch: to prevent mistaps, the first tap marks the point and a second tap on the same point places the stone.
- Undo: against the computer, Undo takes back the computer's move and yours together.