Gomoku · Rules guide
Gomoku rules: how to play five in a row
Five in a row on a 15×15 board, plus the reason the game has three rule sets: the first player wins unless something stops them. Freestyle, standard, Renju's forbidden moves and Swap2 explained.
The short answer
- Players place stones on empty intersections; five in an unbroken line wins.
- Stones never move and are never captured — the board only fills up.
- Freestyle counts six or more as a win; standard Gomoku requires exactly five.
- Renju bans Black from double threes, double fours and overlines to offset the first-player advantage.
- Swap2 balances the game by letting the second player choose which colour to take.
The rules of Gomoku
Gomoku is five in a row on a Go board. Players take turns placing a stone on any empty intersection; stones never move and are never captured; the first to make an unbroken line of five — horizontally, vertically or diagonally — wins. It takes ten seconds to explain and a long time to play well.
- Board: 15×15 intersections is the standard for the competitive game; 19×19 (a full Go board) is also common.
- Black moves first.
- No captures, no passing. Every move adds a stone and nothing is ever removed.
- If the board fills with no five, the game is a draw — which in practice almost never happens.
Freestyle, standard and Renju: three different games
The reason Gomoku has several rule sets is simple: the first player has an enormous advantage. Left alone, Black wins. Every serious rule set is an attempt to fix that.
| Rule set | Line of six or more | Restrictions on Black | First-player advantage |
|---|---|---|---|
| Freestyle Gomoku | Wins | None | Black wins with perfect play (proved 1993) |
| Standard Gomoku | Does not win | None | Still strongly favours Black |
| Renju | Does not win for Black | No double-three, double-four or overline | Black still wins with perfect play (proved 2001) |
| Swap / Swap2 openings | As above | Opening is negotiated | Practically balanced |
Renju's forbidden moves
Renju — the Japanese competitive form — bans Black from three specific shapes, which are legal for White:
- Double three (三三): a move that creates two open threes at once.
- Double four (四四): a move that creates two fours at once.
- Overline (長連): six or more in a row, which does not count as a win for Black.
Playing a forbidden move loses the game immediately. These restrictions turn a lopsided game into a balanced one — at the cost of rules that take some learning.
Swap and Swap2
The modern tournament answer avoids restrictions altogether. In Swap2, the first player puts three stones on the board (two black, one white) and the opponent then chooses to take either colour — or to add two more stones and hand the choice back. Because whoever sets up the position might have to play either side, they are forced to make it fair.
The vocabulary: threes, fours and open shapes
Gomoku has a precise vocabulary, and you cannot discuss the game without it.
| Shape | What it is | Must it be answered? |
|---|---|---|
| Open three | Three in a row with both ends empty and playable | Yes — it becomes an open four |
| Closed three | Three with one end blocked | Usually not urgent |
| Open four | Four with both ends empty | No — it already wins |
| Closed four | Four with one winning point | Yes — block it or lose |
| Double threat | One move creating two threats | Cannot be blocked — this wins |
The one rule that follows from all of this
A four forces your opponent to answer; an open three forces your opponent to answer. So you can drive the game wherever you like by making threats — and the winner is whoever builds two threats that intersect.
Boards, notation and getting started
Competitive Gomoku uses a 15×15 board. Casual play often uses a 19×19 Go board, which changes the game: more space means more room for the defender, so the first-player advantage is a little smaller and games run longer.
Notation is coordinates: columns A–O, rows 1–15. A move is a square, like H8 — the
centre point of a 15×15 board and the standard first move.
Names you will meet: Gomoku (Japanese, "five points"), Renju (the competitive Japanese form), Omok (Korean), Wuziqi 五子棋 (Chinese), and simply Five in a Row.
Common questions
Does six in a row count in Gomoku?
It depends on the rules. In freestyle Gomoku a line of six or more wins. In standard Gomoku and in Renju it does not count for Black — an "overline" is not a win, and in Renju it actually loses.
What is the difference between Gomoku and Renju?
Renju is the competitive Japanese form, which forbids Black from playing double threes, double fours and overlines. Those restrictions exist because plain Gomoku is a first-player win.
Is Gomoku solved?
Yes. Freestyle Gomoku on a 15×15 board was solved by Victor Allis in 1993 — Black wins. Renju was solved in 2001, and Black wins there too, which is why tournaments use balancing openings like Swap2.
What is the best first move in Gomoku?
The centre point. It has the maximum number of lines through it, and every opening theory in the game starts there.
Can Gomoku be a draw?
In theory, if the board fills with no five. In practice it almost never happens on a 15×15 board between players of any strength.
What is Swap2?
A balancing opening: the first player places three stones (two black, one white), and the opponent then chooses a colour, or adds two more stones and passes the choice back. Because you may end up playing either side, you have to make the position fair.
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