Nepedia
Back to Discover
Advanced Reader
🎨

Gomoku

arts Maturity 7-9 Next article →

Gomoku is an abstract strategy board game centered on pattern recognition and tactical planning. The name comes from the Japanese language, where "go" means five and "moku" is a counter for pieces. The objective is simple yet deep: players compete to form an unbroken line of five stones of their color. This line can be horizontal, vertical, or diagonal.

Renju
Renju

Because the pieces are typically not moved or removed once placed, the game can even be played using paper and pencil. While it is often played on a 15×15 grid, historical versions utilized a larger 19×19 board.

To play, two players alternate turns placing stones on the intersections of the grid. Black always takes the first move. The game continues until one player completes a line of five or the board is completely filled. If the board is full and no five-in-a-row exists, the game ends in a draw. In some specific rule sets, a player must form a line of exactly five stones to win. If a player forms a line of six or more stones, it is called an "overline." Under those specific rules, an overline does not count as a victory.

Gomoku-game-1
Gomoku-game-1

The history of Gomoku is tied to Japan's Edo period during the mid-1700s. Historical records suggest the game spread among the people due to the skill of Kuwanaya Buemon. He was a merchant from the tenth generation of his family who frequented the Nijō family. By the late Edo period, around 1850, the game's popularity led to the publication of instructional books. The earliest verified book on Gomoku was published in 1856. The game eventually reached Britain in the nineteenth century, where it was known as "Go Bang." This name was likely a corruption of "goban," the Japanese word for a Go board.

Gomoku-game-3
Gomoku-game-3

A major challenge in Gomoku is the significant advantage held by the first player. In unrestricted play, the black player can often force a win. During the 1989 and 1991 World Championships, the "Pro" opening rule was used. This rule required Black to place the first stone in the center. Under these conditions, Black won 67 percent of the games. This high win ratio proved the game was too unbalanced for fair tournament play. To fix this, professional tournaments adopted the Swap2 opening protocol in 2009.

The Swap2 protocol creates a much more balanced competition. In this version, the first player places three stones: two black and one white. The second player then has three choices to ensure fairness. They can choose to play as Black, play as White and place another white stone, or place two more stones of different colors. If they choose the third option, they pass the choice of color back to the first player. This system has successfully leveled the playing field, bringing the first player's win ratio down to approximately 52 percent.

Swap Rule Gomoku
Swap Rule Gomoku

Many distinct variants exist to change the game's complexity. Renju is a popular version that uses extra rules to limit Black's power. It applies the "three and three" and "four and four" rules to Black only. These rules ban moves that create two open rows of three or two rows of four simultaneously. Another variant, Ninuki-renju, introduces "custodial capture." In this version, a player can capture a pair of stones by sandwiching them lengthwise.

Pro Gomoku
Pro Gomoku

Other versions like Pente and Caro offer different ways to balance the game through overlines or specific row requirements.

Gomoku-game-2
Gomoku-game-2

Gomoku also connects to broader mathematical and theoretical concepts. It is considered a specific type of "m,n,k-game," which is a general category of games played on an m×n board where k stones in a row win. For example, the popular game Connect Four is a variation of this concept. In Gomoku, expert players often engage in "forcing sequences." These are long chains of moves where one player's move forces a specific response from the opponent. Skilled players can accurately read and calculate these sequences, which can last between 20 and 40 moves.

676 words

Where will your curiosity go next?

Keep exploring at your chosen reading level.

🖼️ Images & Media (7)
File:Renju.jpg
Renju.jpg
File:Pro Gomoku.jpg
Pro Gomoku.jpg
File:Swap Rule Gomoku.jpg
Swap Rule Gomoku.jpg
File:Swap2 Gomoku.jpg
Swap2 Gomoku.jpg
File:Gomoku-game-1.svg
Gomoku-game-1.svg
File:Gomoku-game-3.svg
Gomoku-game-3.svg
File:Gomoku-game-2.svg
Gomoku-game-2.svg
More to explore

🔬 Go deeper

More advanced topics to explore

🪜 Step back

Simpler topics to build understanding

What is Nepedia?

A free, ad-free encyclopedia for children. Every article is written at five reading levels, so the same page works for a five-year-old and a fifteen-year-old — use the level switcher above to see this one change. No account needed to read.