Is Gomoku Solved? What the 1993 Proof Means for Players

Yes — free-style gomoku on a 15×15 board was solved in 1993: with perfect play, the first player wins. Here is what that actually means, why the game is still worth playing, and how renju deals with it.

What “solved” means

A game is solved when the outcome under perfect play is known. That does not mean the game is trivial to play — chess is not solved, and neither is go. It means that, in principle, one side has a strategy that cannot be beaten if it is followed exactly.

For gomoku the answer is unusually clean: under free-style rules on a 15×15 board, black wins.

The 1993 proof

In 1993 the Dutch computer scientist L. Victor Allis proved that the first player has a winning strategy in free-style gomoku on a 15×15 board. His proof used a technique called threat-space search, which focuses on the sequences of forcing moves that actually decide gomoku games rather than brute-forcing every position. The result is one of the classic solved games in computer science, alongside checkers and Connect Four.

So why do people still play — and lose?

Because “a winning strategy exists” is not the same as “the winning move is obvious”. The proof establishes that black can force a win; it does not hand you a readable move order for the position in front of you. Human gomoku is still decided by open threes, fours and double threats — the same tactical shapes that beat players in the schoolyard.

Put another way: the theory says black is winning, but most black players are not. A single ignored diagonal is enough to lose the game, and the proof will not save you.

Why renju exists

A game where the first player cannot lose is not much of a competition, so competitive gomoku — renju — gave black a handicap: forbidden overlines, forbidden double fours and forbidden double threes. Those restrictions blunt black's first-move advantage, and renju has not been solved in the same formal sense. That is why serious play uses renju rules rather than free-style.

What the result means for you

Nothing bad. Casual gomoku is not a maths problem — it is a game of threats and attention, and the person who sees one move further usually wins. If you want to improve, work on the shapes in the strategy guide, not on memorising a solution. And if you want a practical demonstration, play the free gomoku board: the computer here is a small pattern-search engine, not a perfect solver, so it is beatable on Medium and even on Hard.

Last updated: November 2026