Gomoku

Overview

Gomoku, known in Japan as gomokunarabe ("Five Piece Line-Up") or Gomoku Narabe, is a traditional two-player board game of Japanese origin, based on the game of go. It is sometimes named Five-in-a-Row, Go Bang, or Go-Moku, and is most commonly played in East Asia (where it is named wǔzǐqí in China and omok in Korea).

It is commonly played on a smaller 15×15 gridded go board (with some variants using the traditional 19×19 board) with traditional go stones, but it can also be played as a paper-and-pencil game due to pieces not being moved or removed. It plays similar to tic-tac-toe and four-in-a-row games (such as Connect Four), as both players take turns placing one of their pieces on the board and attempt to be the first to form a straight connection of five of their pieces (horizontally, vertically, or diagonally).

As with tic-tac-toe and four-in-a-row (all of which are considered m,n,k-games), basic gomoku is a solved game with the first player always able to force a win or a draw with calculated play. Professional variants of the game have additional rules in order to reduce the first player's advantage, with the most well-known variant being renju.

The game, as well as the renju variant, has received multiple video game adaptations since the early 1980's, with most of the dedicated games only released in Japan (as was common with board games of Japanese origin). One of the most well-known games is the 1983 Famicom game Gomoku Narabe Renju, which was one of the earliest games released for the system. The game was also included in multiple table game compilations, including the Clubhouse Games series.

Renju

One of the more well-known professional variants of gomoku, renju handicaps the first player (tentatively Black) in two ways:

• By forbidding the Black player to make any of the three restricted moves (Three and Three, Four and Four, and Overlines). The White player can still use them, and they can force the Black player to make that move to win automatically.

• By having both players follow a complex sequence for the first five moves played (known as the "opening rule"). While it has been evolved over the years, it usually involves the first three moves being one of 26 possible "opening patterns" inside the center 5×5 square of the board, then allowing the second player to choose between being the Black or White player, then having the Black player place two possible moves with the White player choosing which one will proceed.

Many digitized adaptations of gomoku also include renju rules.

Variations

• My Time at Portia features it as a mini-game with the alternate name "Cross-Five"