Gomoku vs Renju: Similar Board, Different Rules

Gomoku and Renju both belong to the five-in-a-row family, but they should not be treated as interchangeable. A casual app may use its own win condition and opening rules. Formal Renju is a specific RIF ruleset for a 15x15 board, with Black-specific forbidden moves and a prescribed opening procedure.

This site's browser game is neither a full formal Renju implementation nor a claim about every game labeled Gomoku. It is a casual exact-five game: a line of exactly five wins, while a line of six or more does not. See our rules page for the scope.

What Stays the Same

Both traditions place black and white stones on intersections and look for lines in horizontal, vertical, or diagonal directions. The important differences appear in the details: how an overline is scored, what Black may create, and which opening procedure a competition uses.

Renju's Forbidden Moves Need Careful Reading

Under the published RIF rules, Black begins at the center. White wins by attaining five or an overline. Black may lose by making an overline, a double-four, or a forbidden double-three. The double-three rule is not a simple visual shortcut: the official definition includes recursive checks for whether the apparent threes can legally become straight fours. A diagram that labels every crossing pair of threes illegal can therefore mislead players.

The RIF rules also list 13 direct and 13 indirect opening patterns. The tentative Black makes the first three moves, the tentative White chooses colors, the player now White makes the fourth move, and Black proposes two fifth moves from which White chooses. That is the published RIF procedure, not an automatic rule for every Renju event, local club, or online app.

What Does “Solved Gomoku” Actually Mean?

Victor Allis's computer-search research established a first-player win for a defined 15x15 unrestricted Gomoku setting. The result is useful context for why competitive rule systems address first-player advantage, but it does not automatically apply to Renju, a free-style app, another board size, or this site's exact-five rules. It also does not predict the result of an ordinary human game.

This site has not found a published weak or strong solution for standard Renju. That is a statement about the sources reviewed here, not proof that no such research can exist. Read our scope note on solved games for the cited research and limits.

Which Version Should You Learn First?

For a casual game, start by agreeing on the board size and overline rule. A simple exact-five or free-style game is easier to begin with. If you want to play formal Renju, learn the RIF definitions directly rather than importing simplified pattern labels from a casual guide. The key transferable skills are scanning all four directions, recognizing immediate winning moves, and checking your opponent's threats.

Frequently Asked Questions