Gomoku, known as Omok (오목) in Korean and Gobang in some Western traditions, is one of the oldest and most widely played board games in the world. Its origins trace back thousands of years to ancient China, and it has since become a beloved pastime across East Asia and beyond. Despite its simple rules, Gomoku offers remarkable strategic depth that has captivated casual players and competitive minds alike.
Gomoku is played on a 15x15 grid of intersecting lines. Unlike chess or checkers, stones are placed on the intersections of the lines, not inside the squares. This gives the standard board a total of 225 possible positions where a stone can be placed. Some variations use a 19x19 Go board, but the 15x15 board is the official standard for competitive Gomoku and is what we use here on Omok Online.
A B C D E F G H I J K L M N O 15 . . . . . . . . . . . . . . . 14 . . . . . . . . . . . . . . . 13 . . . . . . . . . . . . . . . 12 . . . . . . . . . . . . . . . 11 . . . . . . . X . . . . . . . 10 . . . . . . X O . . . . . . . 9 . . . . . X O . . . . . . . . 8 . . . . X O . . . . . . . . . 7 . . . . O . . . . . . . . . . 6 . . . . . . . . . . . . . . . 5 . . . . . . . . . . . . . . . 4 . . . . . . . . . . . . . . . 3 . . . . . . . . . . . . . . . 2 . . . . . . . . . . . . . . . 1 . . . . . . . . . . . . . . . X = Black stones O = White stones Black has 4 in a diagonal row - one more to win!
Two players take turns placing stones on the board. One player uses black stones and the other uses white stones. Once a stone is placed on the board, it cannot be moved or removed for the rest of the game. This is a key difference from games like chess, where pieces move around the board throughout the game.
The player with the black stones always goes first. Because going first provides a significant strategic advantage in Gomoku, tournament play often includes special opening rules to balance this. In casual games on Omok Online, the room creator chooses their color, and black always takes the first turn.
Players alternate turns, each placing one stone per turn on any empty intersection of the board. Black places the first stone, followed by white, and so on. There is no passing in standard Gomoku; you must place a stone on your turn. The game continues until one player achieves the winning condition or the board is completely filled.
The objective is simple: be the first player to form an unbroken line of exactly five stones of your color. This line can run in any of four directions:
The five stones must be consecutive with no gaps and no opponent stones between them. As soon as a player completes a row of five, they win immediately, regardless of whose turn it is.
If all 225 intersections on the board are filled and neither player has achieved five in a row, the game ends in a draw. Draws are relatively rare in practice, as most games conclude well before the board is full.
In the standard free-style rules used on Omok Online, forming six or more stones in a row (called an overline) still counts as a win. However, in some professional rulesets such as Renju, overlines are forbidden for the black player and do not count as winning. On Omok Online, we use free-style rules where any five or more consecutive stones wins the game.
In professional Gomoku variants like Renju, the black player is subject to additional restrictions to compensate for the first-move advantage. These include bans on double-three, double-four, and overline formations. On Omok Online, we use standard free-style rules with no forbidden moves, making the game accessible and easy to learn for all players.
Gomoku is a game of pure strategy with no element of luck. Every move is a choice, and the best player wins through superior planning, pattern recognition, and tactical execution. Whether you are a complete beginner or a seasoned player, understanding these basic rules is the foundation for enjoying everything the game has to offer. Ready to play? Head back to the main page and start a game!