Open Four · 活四
Four stones with both ends open — unstoppable, wins on the next move.
Gomoku Rules
Gomoku — also called Five in a Row — is a two-player abstract strategy game. The rules are short to learn but the tactics run deep. Here is everything you need to set up a legal game and recognize the basic shapes.
Objective
- Win by placing five of your own stones in an unbroken line — horizontally, vertically, or diagonally.
- Exactly five stones win. On the free gomoku ruleset a longer line (six or more) is also a win; the competitive Renju ruleset treats a six-in-a-row as a forbidden loss for Black (see below).
Turn Order
- Black moves first, then the players alternate, placing exactly one stone per turn.
- Stones are placed on the intersections of the grid and are never moved or removed once played.
Board
- The standard board is 15×15 intersections.
- Smaller 13×13 boards and larger 19×19 boards are also used as variants; the winning rule is always five in a row.
Forbidden Moves
- On the free gomoku ruleset there are no forbidden moves — either color may build any line.
- The competitive Renju ruleset restricts Black only: Black may not play a double-three, double-four, or overline. White has no restrictions. See the Renju rules page for the full details.
Draw
- If the board fills completely with no five-in-a-row made, the game ends in a draw.
Basic Terms
A few shapes every player should know. The full list lives in the glossary:
Straight Four (Four) · 冲四
Four in a row with one open end; the opponent must block it.
Open Three · 活三
A three that can become an open four on the next move.
Broken Three · 眠三
A three that needs a specific point to extend; lower priority than an open three.
Frequently Asked Questions
Is gomoku the same as Go?
No. Go (Weiqi) is played on a 19×19 board where you capture stones and claim territory. Gomoku is played for five-in-a-row on a 15×15 board with no captures.
Can Black win on the first move?
No. A single stone cannot make five in a row. Black's advantage shows up later, which is exactly why the Renju ruleset adds forbidden moves to keep the game balanced.
Does five in a row have to be exactly five?
Under standard free gomoku, exactly five wins and a line of six or more is also a win. Under Renju, six or more (an overline) is a forbidden loss for Black.
Who goes first in gomoku?
Black always moves first, then players alternate. Many casual games decide color by a coin flip or a "guess the stone" ritual.