What is Gomoku?
Gomoku, also called Five in a Row, is a two-player strategy game played with black and white stones on the intersections of a 15 by 15 grid. Its Japanese name, gomoku narabe, means “five pieces in a row”. Koreans know it as omok, Chinese players as wuziqi, and in Britain an old variant was sold as Go-Bang.
The game uses Go equipment but none of Go’s capturing rules. Stones never move or leave the board, so every move stays where it is and the board fills up until someone completes a line.
Because Black moves first, Black has a real head start. In 1994 the computer scientist Victor Allis showed that with perfect play Black always wins free-style Gomoku on a 15 by 15 board. Renju, the tournament form of the game, adds restrictions on Black to even things out.
The basic rules
- Black plays first; after that the players alternate, one stone per turn.
- Stones go on empty intersections and stay there for the rest of the game.
- The first player to make an unbroken line of five stones across, down or diagonally wins.
- If the board fills up and nobody has five, the game is a draw.
Renju rules and forbidden moves
Renju (連珠, “connected pearls”) is the name the Japanese journalist Kuroiwa Ruikō gave the game in 1899, and it is the rule set used in official tournaments. Its purpose is to reduce Black’s first-move advantage, so the restrictions apply to Black only.
Under Renju, Black wins only with exactly five stones in a row. Three shapes are forbidden for Black, and on this site a red × marks every point where Black may not play.
The three forbidden moves for Black
Double-three (3-3)
A move that creates two open threes at once. An open three is a three that can become an open four with one more stone.
Double-four (4-4)
A move that creates two fours at once, even when both fours lie on the same line.
Overline (six or more)
A move that makes six or more black stones in a row. It does not win for Black and is not allowed.
Exceptions worth knowing
Five comes first
If Black’s move makes exactly five, Black wins, even if the same stone also forms a 3-3 or a 4-4.
A blocked three does not count
Here one three is capped by White, so it can never become an open four. Only one real three remains, so the move is legal.
- Four-three (4-3), one four plus one open three, is legal and is Black’s main way to win.
- A three only counts if the point that would turn it into an open four is itself legal for Black. A “false three” does not make a double-three.
- White has no forbidden moves and also wins with six or more in a row.
- White can win by forcing Black to defend on a forbidden point, because Black cannot block there.
Winning strategies and tactical patterns
Most Gomoku games are decided by threats: shapes that force a reply. Learn to see these four patterns for both colours and you will spot wins and losses several moves ahead.
Open four
Four in a row with both ends empty. It cannot be stopped: whichever end the opponent blocks, you play the other.
Half-open four
Four stones with one way to make five, such as a four blocked at one end or a split four like ●●·●●. It must be blocked at once.
Open three
Three stones that can become an open four next move. Block it now, or answer with a four of your own.
VCF, victory by continuous fours
Black plays 1, 3 and 5, each a four that White must block with 2 and 4. Move 5 makes a four and an open three at once, and White cannot stop both.
A VCF is a sequence where every attacking move makes a four. Because each four must be blocked immediately, the defender never gets a free move, and the attack ends with a five or a double threat.
When there are not enough fours, players use VCT, victory by continuous threats, which mixes fours with open threes. It is slower but harder to see coming.
Practical tips
- Start near the centre, where lines can grow in every direction.
- Build shapes that point in two directions at once; one line is easy to block.
- Before you attack, check whether your opponent has a four or an open three that comes first.
- Block an open three at the end that also helps your own stones.
- As Black under Renju, aim for 4-3 and keep your 3-3 and 4-4 points in mind.
- As White, look for ways to make Black’s only defence a forbidden point.
Ways to play on this site
vs AI
Three levels, from a relaxed opponent to one that reads forcing sequences. It runs in your browser, so it answers quickly and works offline once the page has loaded.
Pass & Play
Two people on one phone, tablet or computer, taking turns.
Quick Match
Pairs you with another player online under Renju rules. If nobody is free, start against the AI with one tap.
Play a Friend
Creates a private room with its own link. Your friend opens it and the game starts; you can offer a rematch with colours swapped.
Frequently asked questions
Is this Gomoku game free?
Yes. Every mode is free and needs no account or download. The site is supported by ads shown below the board.
What is the difference between Renju and free-style Gomoku?
In free-style Gomoku both players may play anywhere and five or more in a row wins. Under Renju, Black may not make a double-three, a double-four or an overline, and Black wins only with exactly five. Renju makes the game fairer for White.
Why can’t I place a black stone on some points?
Under Renju rules those points would give Black a forbidden shape: a double-three, a double-four or an overline. They are marked with a red ×. Switch to free-style rules if you want to play without restrictions.
What happens if nobody is online for a Quick Match?
While you wait, the matching screen shows a Start Immediately with AI button. Tap it at any time and your search is cancelled and a game against the AI begins on the same board.
How do I play with a friend?
Choose Play a Friend, pick the rules and create an invite link. Send the link to your friend; the game starts as soon as they open it. If either of you loses connection, reopening the link returns you to the same seat.
How strong is the AI?
Easy plays loosely and misses some threats. Medium looks a few moves ahead and blocks reliably. Hard searches forcing sequences of fours and punishes loose play.
Can I play on a phone?
Yes. On touch screens you can turn on Tap twice to place: the first tap shows where your stone will go and a second tap on the same point confirms it, so a slip of the finger does not cost you the game.
Are Gomoku, Omok and Five in a Row the same game?
Yes. They are names for the same game in different countries. Renju is its rule set for tournaments, and Gobang or Go-Bang are older names used in some places.