Renju is the professional variant of Gomoku

Gomoku

Gomoku is an abstract strategy board game. Also called Gobang or Five in a Row, it is traditionally played with go pieces on a go board ; however, because once placed, pieces are not moved or removed from the board, gomoku may also be played as a paper and pencil game...

, a board game

Board game

A board game is a game which involves counters or pieces being moved on a pre-marked surface or "board", according to a set of rules. Games may be based on pure strategy, chance or a mixture of the two, and usually have a goal which a player aims to achieve...

 originated from Japan

Japan

Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

 in Heian Period

Heian period

The is the last division of classical Japanese history, running from 794 to 1185. The period is named after the capital city of Heian-kyō, or modern Kyōto. It is the period in Japanese history when Buddhism, Taoism and other Chinese influences were at their height...

. It was named Renju by Japanese journalist Ruikou Kuroiwa (黒岩涙香) on December 6, 1899 in a Japanese newspaper Yorozu chouhou (萬朝報) . It is played with black and white stones on a 15x15 intersection Go

Go (board game)

Go , is an ancient board game for two players that originated in China more than 2,000 years ago...

 board. Renju eliminates the "Perfect Win"-situation in Gomoku by adding special conditions for the first player (Black).

Rules

Unlike Gomoku, Renju has a unique sequence of opening moves:

1. The first player places 2 black stones and 1 white stone on the board.
2. The second player now chooses whether to play black or white.
3. White then places one more stone on the board.
4. Black places 2 stones on the board.
5. White removes one of the two black stones from the previous move.
6. White places a white stone.

After this sequence is complete, Black and White continue to take turns to place their stones.

The Extra General Assembly of Renju International Federation in 2008 created 3 new sets of rules for openings that are to replace the above old sequence of moves: Soosörv, Taraguchi, and Yamaguchi. Also a rejection system for their use was approved.

There are certain moves that Black is not allowed to make:

• Double three - Black cannot place a stone that builds two separate lines with three black stones in unbroken rows (i.e. rows not blocked by white stones).
• Double four - Black cannot place a stone that builds two separate lines with four black stones in a row.
• Overline - six or more black stones in a row.

Black can win the game only by placing five black stones in a row (vertically, horizontally or diagonally).

White can win by either:

• getting five (or more) white stones in a row
• forcing Black to make a forbidden move (see above).

World championships

World Championships in Renju have occurred every second year, since 1989.http://www.renju.net/media/wc.php

Previous World Championships have taken place in the following places:

• 1989: Kyoto, Japan
• 1991: Moscow, USSR
• 1993: Arjeplog, Sweden
• 1995: Tallinn, Estonia
• 1997: Saint Petersburg, Russia
• 1999: Beijing, China
• 2001: Kyoto, Japan
• 2003: Vadstena, Sweden
• 2005: Tallinn, Estonia
• 2007: Tyumen, Russia
• 2009: Pardubice, Czech Republic

The next World Championship will take place in Huskvarna, Sweden.

See also

• Game complexity
  Game complexity
  Combinatorial game theory has several ways of measuring game complexity. This article describes five of them: state-space complexity, game tree size, decision complexity, game-tree complexity, and computational complexity.-Measures of game complexity:...
  
  
• Connect6
  Connect6
  Connect6 introduced in 2003 by Professor I-Chen Wu at Department of Computer Science and Information Engineering, National Chiao Tung University, is a two-player game similar to Gomoku....
  
  
• Go (board game)
  Go (board game)
  Go , is an ancient board game for two players that originated in China more than 2,000 years ago...
  
  
• Five in a Row (game)
• Irensei
  Irensei
  Irensei is an abstract strategy board game. It is traditionally played with Go pieces on a Go board , but any equipment with which Go can be played is also suitable for Irensei....
  
  

External links

• Renju International Federation has complete rules and history of the game