The History of Gomoku
A simple line-them-up game whose very simplicity forced competitive players to change its rules.
Ancient Roots, Modern Name
Games built around lining up stones on a grid go back centuries across East Asia; the specific rules now known as Gomoku took shape in Japan, where its name (五目並べ, gomokunarabe) simply means "five points in a row."
It's traditionally played with the same black-and-white stones and grid-crossing board as Go, making it an easy, low-equipment variant that generations of Go players picked up as a quick side game.
From Casual Pastime to Renju
Because Gomoku's plain rules give the first player (traditionally Black) a significant built-in advantage, a stricter competitive variant called Renju emerged in Japan in the early 20th century, adding extra restrictions - forbidding Black from certain double-three or double-four setups - to level the playing field.
Renju became the standard for serious tournament play, while the simpler, unrestricted ruleset played here (often called "freestyle" Gomoku) remained the more common casual version worldwide.
A Solved First-Player Win
In 1994, researcher L. Victor Allis proved through exhaustive computer analysis (a technique called proof-number search) that freestyle Gomoku on a standard board is a forced win for the first player with perfect play.
That result is exactly why competitive Renju exists: without its extra restrictions on Black, tournament Gomoku would be a solved formality rather than a real contest - a rare case where a solved game directly reshaped how it's played competitively, rather than just being an interesting footnote.