Gomoku (also called Five in a Row) is a free online board game you can play instantly in your browser against a computer opponent named Otto, no download, no account, and no waiting for another player. Play on the traditional 15x15 board: tap any empty intersection to place your black stone, then Otto answers with a white stone. The first side to line up five stones in a row horizontally, vertically, or diagonally wins. Play through 15 levels that make Otto stronger with every match, from loose, scattered opening moves early on to tight blocking and multi-direction threats near the final board. Win a level to unlock the next opponent strength; Try Again starts a fresh match at the same difficulty.
How to play Gomoku
- Choose any empty intersection on the 15x15 board to place one of your black stones.
- Otto, the computer opponent, places a white stone after your move unless the game has already ended.
- Win by connecting five of your stones in a straight line horizontally, vertically, or diagonally.
- Five or more in a row both count as a win — there is no forbidden "overline" rule in this freestyle version.
- If all 225 intersections fill without either side connecting five, the match is a draw and you can replay the level.
- Clear a level to unlock the next one, where Otto reads farther across the board and blocks more dangerous threats.
Tips
- Open near the center — a center stone participates in far more potential five-in-a-row lines than one near the edge.
- Watch for "open threes" (three in a row with both ends empty); left unblocked, they turn into an unstoppable open four next turn.
- Build threats in two directions from the same stone so Otto cannot block both with a single move.
- Before placing a stone, check whether Otto already has four in a row with an open fifth space — blocking an immediate loss always comes first.
FAQ
Is Gomoku free to play?
Yes. Gomoku is completely free to play online with no download, no account, and no in-game purchases.
Does Gomoku work on mobile?
Yes — tap any empty intersection to place a stone, so it works on phones, tablets, and desktop.
What is the goal of Gomoku?
Also known as Five in a Row, the goal is to be the first player to place five of your own stones in an unbroken line horizontally, vertically, or diagonally.
Can I play Gomoku against another person online?
This version is single-player against a computer opponent named Otto, so there is no lobby, matchmaking, or waiting for another player.
How many levels does Gomoku have?
There are 15 levels. Otto starts with loose, scattered play on early levels, then reads farther across the board and blocks threats more reliably as you advance.