Five in a row. No captures, no promotion, nothing but placement — and yet Gomoku is deep enough that computers only "solved" the free-style version after serious effort, and human tournaments still thrive. The whole game turns on one concept: the unstoppable threat. Learn to build them and to smell them coming, and your win rate transforms.
The vocabulary of threats
Every Gomoku position is read in terms of rows-in-progress:
- Open three — three stones in a row with both ends empty (·●●●·). Left alone, it becomes an open four, which is unstoppable. An open three demands a response.
- Closed three — three in a row blocked on one end. Much weaker; it can only ever become a closed four.
- Open four — four with both ends empty (·●●●●·). Game over: two winning squares, one block available.
- Closed four — four blocked on one end. A one-move threat: it must be blocked right now, but it can be blocked.
The winning pattern in almost every Gomoku game is a double threat: one move that creates two of the above at once — a "four-three" (a closed four plus an open three) or a "double three". Your opponent blocks one; the other wins. Everything before that moment is preparation.
Attack with junctions
Strong Gomoku moves sit at junctions — points where two or more of your potential lines cross. A stone that extends a horizontal pair and starts a diagonal is quietly worth two moves. Build clusters whose lines radiate in several directions rather than one long naked row that's trivially blocked. The classic shape is a loose diagonal ladder of pairs — innocuous for two moves, suddenly threatening everywhere.
Defend early, not heroically
Beginners block fours. Good players block threes — specifically open threes, the move before the crisis. Better still is the pre-emptive block at the junction where your opponent's shapes would meet. Two guidelines:
- An enemy open three outranks almost any attacking idea of yours — block it (or answer with a four of your own, which forces them to respond and gives you the initiative back).
- When blocking, prefer the end that also does something for your position — defence that develops is double value.
Tempo: the forcing sequence
A closed four forces a response — you effectively get a free move elsewhere afterwards. Chains of forcing moves (four, block, four, block…) let a player rearrange the board single-handedly, herding the opponent's stones into position until a double threat lands. When you spot two or three potential fours in your position, look for the sequence — forced wins in Gomoku are long but they're real. Conversely, when you're being dragged through forced blocks, look for a block that simultaneously creates your own four — the counter-punch that breaks the chain.
First player, second player
Going first in Gomoku is a genuine, mathematically proven advantage in the unrestricted game — with perfect play, Black wins. Nobody plays perfectly, but the practical advice stands: as Black, attack — you're a tempo ahead, so force the pace and never hand back the initiative with passive moves. As White, contest early — play close to Black's stones, deny junctions, and hunt for counter-threats; passivity loses slowly but surely. (Tournament rule sets like Renju add opening restrictions on Black to rebalance — casual play, including RivalPit's 15×15 board, uses the free rules.)
Habits that raise your level fast
- Scan all four directions around every new enemy stone — diagonal threats are the ones people miss.
- Before each move, name your threat: "this makes an open three" — if the answer is "nothing", find a junction move instead.
- Count enemy shapes: two separate open twos aimed at the same junction is an alarm, not a curiosity.
- Play the centre early — lines through the middle have more room to become fives.