Gomoku
Play Five in a Row against a computer opponent or with a friend.
Gomoku
Play Five in a Row against a computer opponent or with a friend.
About Gomoku
Same-device play on a 15 by 15 board
The game uses a 15 by 15 board. Black moves first, players place stones on empty intersections, and the first side to connect five horizontally, vertically, or diagonally wins. Two-player mode is local same-device play.
Live shapes and dead shapes
To judge whether a run of stones is worth anything, look at both ends. Three in a row with both ends open is a live three: block one side and the other is still there. Once one end is blocked the run has only one direction left and is worth far less, and a run blocked at both ends is worth nothing at all, which is exactly how the computer here scores it. Before placing a stone, count how many directions your run can still grow in rather than how many stones it already has.
Building a threat that cannot be blocked
A single threat is easy to answer: your opponent blocks it and the position is calm again. Games are decided by opening two threats at once, for example by playing the intersection of two live threes so that one blocking move can only cover one of them. When choosing where to play, prefer squares that take part in two directions at the same time, which usually means the crossing points of your existing stones rather than the far end of a line. The computer here scores every empty point by its single best direction, so those crossing points are undervalued and this tactic works especially well against it.
Casual local CPU opponent
CPU mode searches candidate moves near existing stones and uses a heuristic minimax depth of 1, 2, or 3 for easy, medium, and hard. It supports undo and reset, but it is not an online multiplayer room, rating ladder, or official tournament-rule engine.
FAQ
Common questions and answers about this topic.
How do you play Gomoku?
Players alternate placing black and white stones on the 15×15 board. The first to connect five stones in a row—horizontally, vertically, or diagonally—wins. Black moves first.
How strong is the computer opponent?
The AI uses a lookahead search that blocks immediate four-in-a-rows and takes winning moves when available. It is tuned for casual play rather than tournament strength—advanced players can usually out-plan it.
Can two people play on the same device?
Yes. Switch the mode selector to "Two Players" and the AI turns off—both players take turns tapping on the same screen.
Do I need to sign up or install anything?
No. Gomoku runs entirely in your browser—no account, no download, no tracking of your moves.
What counts as a draw?
If every cell on the board is filled and neither side has five in a row, the game ends in a draw.
Does Black have an advantage by moving first?
Yes. Under free-style rules with no forbidden moves, Gomoku has been proven to be a first-player win, which is why tournament rulesets add forbidden moves for Black or an opening swap. This tool uses free-style rules with no forbidden moves and is meant for casual play; to even things out, take turns going first, or let the more experienced player take White.
Does a line of six or more also win?
Yes. The tool only checks for five stones in a row, and any longer line already contains five, so it wins just the same. Some tournament rulesets treat an overline by Black as a forbidden move and a loss; this tool does not use that rule.
How can I beat the computer on Hard?
Hard searches three plies ahead, so simply lining up four stones will always be blocked. What works is creating two threats that hold at the same time, so one move cannot answer both. The computer scores every empty point by its single best direction, which leaves the crossing points of two lines undervalued. It also only picks moves near existing stones and never starts a new area on its own, so you can use that to prepare a second line elsewhere.