Gomoku

Gomoku is a two-player strategy game played by placing stones on a grid. The first player to form an unbroken line of five stones wins.

Open four: A row of four stones with an empty point at both ends, allowing a win on either end next turn. This immediate double-ended threat is one of Gomoku’s strongest tactical patterns.
Go board: A grid of intersecting lines used to play Go and several other stone-placement games. Gomoku is commonly played on a Go-style grid, with stones placed at line intersections.
Go: A two-player board game in which players place stones to control territory on a grid. Gomoku uses the same general stone-and-grid format, though its objective is different.
Renju rules: A rule system for Renju that restricts certain moves by the first player to reduce its advantage. Renju restrictions distinguish it from unrestricted Gomoku, especially around double threats.
AlphaZero: A game-playing system that learned Go, chess, and shogi through self-play and search. Its learning-and-search approach illustrates methods also studied in Gomoku engines.
Double three: A move that creates two distinct open-three threats at once. In rule sets that forbid it, this tactic is illegal for the first player.
Five in a row: A family of games whose objective is to form a straight line of five marks or pieces. Gomoku belongs to this broader family of line-making games.
Renju: A competitive five-in-a-row game with restrictions designed to balance the first player's advantage. Renju developed as a rule-governed competitive form of the Gomoku tradition.
Freestyle Gomoku: A Gomoku variant in which a line of five or more stones wins. Its overline rule differs from versions requiring exactly five stones.
Monte Carlo tree search: A search method that estimates move value through repeated simulations of possible play. It offers an alternative to exhaustive tactical search in large Gomoku positions.

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Tic-tac-toeCompared with: Its longer winning line and larger board create a much deeper search problem.