Gomoku: five stones in a row

Gomoku: five stones in a row has one of the simplest win conditions in strategy gaming — place stones on the grid, and be the first to connect five of them in a straight line, horizontally, vertically, or diagonally. That simplicity is deceptive: because there's no capturing or removing stones, every placement is permanent, which means defense is just as active as offense. Strong play here means constantly watching for your opponent building an open three or four in a row and blocking it before it becomes unstoppable, not just racing to build your own line. It's an easy game to learn in under a minute but genuinely difficult to play well against a sharp opponent, which is exactly why it's remained popular as a serious strategy game for centuries. Play it free in the browser, no download or account needed to start a match.