Gomoku (Five in a Row)

The Ultimate Guide to Gomoku (Five in a Row)

Gomoku — also known as Five in a Row, Gobang, or Wuziqi (五子棋) — is one of the oldest and most elegant abstract strategy games in the world. Originating in ancient China over 4,000 years ago during the later part of the Stone Age, Gomoku evolved alongside its cousin Go (Weiqi) and spread throughout East Asia, becoming especially popular in Japan, Korea, and China where professional tournaments draw serious competitive players.

The game's deceptively simple objective — place five stones in an unbroken row — belies a rich strategic depth that has captivated mathematicians, computer scientists, and competitive players for centuries. Gomoku was one of the first board games to be computationally solved: in 1994, Victor Allis proved that with perfect play the first player wins on a standard 15×15 board without restrictions, leading to the adoption of various opening rules in competitive play.

How to Play Gomoku — Complete Rules

Objective

Be the first player to place five (or more) of your stones in an unbroken line — horizontally, vertically, or diagonally — on the game board.

Board & Pieces

• Gomoku is traditionally played on a 15×15 grid (the same board used for Renju), though 19×19 Go boards are also common.
• Two players alternate placing black and white stones on the intersections of the grid lines.
• Black always moves first in standard play.
• Once placed, stones are never moved or removed from the board.

Gameplay

1. Black places the first stone on any intersection.
2. Players alternate turns, each placing one stone per turn on any empty intersection.
3. The game ends immediately when one player forms an unbroken line of exactly five stones in any direction (horizontal, vertical, or diagonal).
4. If the entire board fills up with no five-in-a-row, the game is a draw (extremely rare in practice).

Overlines (Six or More in a Row)

In free-style Gomoku (the most common casual variant), a line of six or more stones still counts as a win. In standard/Renju-style Gomoku, overlines (six+) do not count as a win for Black, though they do for White. This distinction matters primarily in competitive play.

Gomoku Game Specifications

Gomoku Strategy — Tips to Win More Games

1. Control the Center

The center of the board offers the most possible line directions. A stone at the center intersection participates in the maximum number of potential five-in-a-row combinations. Opening near the center gives you superior reach in all directions.

2. Build Open Threes

An open three is three stones in a row with both ends unblocked. This is the most dangerous threat in Gomoku because your opponent must block one end, but you can extend from the other. A single open three forces a defensive response; two simultaneous open threes (a "double three") is almost always an immediate win.

3. Create a Double Threat (Fork)

The key to winning Gomoku is creating two simultaneous threats that your opponent cannot both block in one move. This can be:

• Double open three: Two open threes formed at once — forces a win next turn.
• Open three + open four: One threat must be blocked immediately, leaving the other free to complete.
• Double four: Two lines of four at once — impossible to block both.

4. Think Ahead — Read the Board

Strong Gomoku players think 3–5 moves ahead, tracing sequences of forced moves (threats that the opponent must answer). This skill, called reading, is similar to calculating variations in chess. If you can set up a chain of forcing moves that leads to a double threat, you've won.

5. Block Aggressively

Never ignore your opponent's open threes or growing lines. A missed block often means the game is over in 1-2 moves. When blocking, try to place your stone where it simultaneously defends and extends one of your own lines — combining offense and defense in a single move.

6. Avoid Dead Shapes

A "dead" formation is one that is blocked on both ends and can never become five in a row. Avoid building lines that run into the board edge or your opponent's stones on both sides. Every stone should contribute to a live (extendable) formation.

7. Use the Diagonal

Beginners tend to focus on horizontal and vertical lines while overlooking diagonal threats. Diagonal lines are harder for opponents to spot visually, especially on a crowded board. Build diagonal sequences early to create less-obvious attack vectors.

Gomoku Variants & Related Games

Glossary of Gomoku Terms

• Five in a Row — The winning condition: an unbroken line of 5 stones (horizontal, vertical, or diagonal).
• Open Three — Three stones in a line with both ends empty; one move from an open four.
• Closed Three — Three stones in a line with one end blocked; less threatening than an open three.
• Open Four — Four stones in a line with both ends empty; guaranteed win on the next move.
• Closed Four (Straight Four) — Four stones with one end blocked; opponent can still block the other end.
• Double Three (Fork) — A move that creates two open threes simultaneously; virtually unblockable.
• Double Four — A move that creates two lines of four simultaneously; wins immediately.
• Overline — Six or more stones in a row; counts as a win in free-style but not for Black in standard/Renju rules.
• VCT (Victory by Continuous Threats) — A sequence of forcing moves where every move is a threat, leading to an unstoppable five.
• VCF (Victory by Continuous Fours) — A VCT where every forcing move specifically creates a four.
• Tenuki — (from Go) Playing in a different area of the board instead of responding locally to the opponent's last move.
• Joseki / Opening — Established opening stone sequences studied and memorized by competitive players.

Frequently Asked Questions About Gomoku

What is Gomoku?

Gomoku (also called Five in a Row or Gobang) is a two-player abstract strategy board game where players alternate placing black and white stones on a grid. The objective is to be the first to create an unbroken line of five stones in any direction — horizontally, vertically, or diagonally. It originated in ancient China over 4,000 years ago.

What size board is used for Gomoku?

The standard competitive Gomoku board is 15 × 15 intersections. However, the game can also be played on a 19 × 19 Go board, which is common in casual play. Smaller boards (like 9×9) are sometimes used for beginners or speed games. The game always uses the intersections of the grid lines, not the squares.

Is Gomoku a solved game?

Yes. In 1994, researcher Victor Allis mathematically proved that on a 15×15 board with no restrictions (free-style Gomoku), the first player (Black) wins with perfect play. This is why competitive Gomoku often uses balancing rules like Renju restrictions or swap openings to ensure fair games between skilled players.

What is the difference between Gomoku and Renju?

Renju is a competitive variant of Gomoku designed to offset Black's first-move advantage. In Renju, Black has three additional restrictions: Black cannot make a double-three, a double-four, or an overline (6+ in a row). White has no such restrictions. This creates a more balanced game for tournament play. Standard (casual) Gomoku has no restrictions for either player.

Does six in a row count as a win?

In free-style Gomoku (the most common casual version), yes — six or more in a row counts as a win for both players. In standard Gomoku and Renju, an overline (6+) does not count as a win for Black, though it does for White. This rule prevents Black from exploiting the first-move advantage.

Who goes first in Gomoku?

Black always goes first in standard Gomoku. This gives Black a proven mathematical advantage on an unrestricted board. In competitive play, various opening rules (such as the swap rule, where the second player can choose to swap colors after seeing the first move) are used to balance this advantage.

What is an open three in Gomoku?

An open three is a line of three consecutive stones with both ends unblocked (empty intersections on both sides). It is the fundamental building block of Gomoku attacks because it threatens to become an open four on the next move, which is unstoppable. Creating two open threes simultaneously (a "double three" or fork) almost always guarantees a win.

What is the difference between Gomoku and Connect Four?

Both games involve getting pieces in a row, but they play very differently. Connect Four uses a 7×6 vertical board with gravity — pieces drop to the lowest available row. Gomoku uses a flat 15×15 grid where stones can be placed on any empty intersection. Gomoku requires 5 in a row (vs. 4) and has no gravity, giving it a vastly larger game tree and more strategic complexity.

How long does a Gomoku game last?

A typical Gomoku game lasts between 30 and 70 moves (15–35 per player). Games between beginners may be shorter if one player misses a threat. Games between advanced players can go longer as both sides carefully build and block. The maximum possible game length on a 15×15 board is 225 moves (every intersection filled), though draws are extremely rare.

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