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, omok (오목) in Korean and wuziqi (五子棋) in Chinese — 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.
Is omok the same as gomoku?
Yes. Omok (오목) is the Korean name for gomoku, and wuziqi (五子棋) is the Chinese name. All three play five in a row on a 15×15 board with no captures — the rules are identical.