''Renju'' (Japanese: 連珠) is a professional variant of

gomoku ''Gomoku'', also called ''Five in a Row'', is an abstract strategy board game. It is traditionally played with Go pieces (black and white stones) on a Go board. It is played using a 15×15 board while in the past a 19×19 board was standard. Be ...

. 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). The name "renju" comes from the Japanese language, and means "connected pearls" in Japanese. The game is played with black and white stones on a 15×15 gridded

go board Go equipment refers to the board, stones (playing pieces), and bowls for the stones required to play the game of Go. The quality and materials used in making Go equipment varies considerably, and the cost varies accordingly from economical to ex ...

. The rule of renju weakens the advantages for the first player (Black) in gomoku by adding special restrictions for Black.

Rules

Opening rules

Unlike gomoku, renju has a unique sequence of opening moves called an "opening rule". There are several certified opening rules. The list of requirements for new opening rules as approved by the

Renju International Federation The Renju International Federation (RIF) is an international organization which was founded in Stockholm, Sweden on August 8, 1988. The main purpose of the federation is to unite all the Renju and gomoku national federations all over the world, or ...

(RIF) in 2003 was: I. Traditions * The basic renju rules must be kept. * The opening stage must not exceed 5 moves. * All 26 canonical openings must be possible and only 26 canonical openings can be possible. * All present realistic variants must be possible. * The moves located very closely near the edges of a board during the opening stage are not preferable. II. Simplicity and attraction * New rules must be simple to study. * New rules must be simple to play for beginners. The situation when in significant part of cases a beginner will have the lost position already after the first 5 moves is not good. * The rules must be systematic and attractive. III. Creativity * The number of possible creative variants must be significantly greater than now. These variants must be achieved under the optimal strategy of both players. * The chances of sides to win must be practically equal. * The situation when during the opening stage the player who make a move does not interested in the forming of equal and creative position is not preferable. (Example: indirect 2nd move in previous opening rules). * The rules must give the chance for both players to avoid the position after the opening stage well known for the opponent. * The knowledge of theory and deep own analyses must give an advantage but the player with a good imagination must have chances against this. An example of such opening rule (namely "

RIF opening rule RIF opening rule is a renju opening rule. It was adopted by the Renju International Federation The Renju International Federation (RIF) is an international organization which was founded in Stockholm, Sweden on August 8, 1988. The main purpose of ...

") follows. # The first player places 2 black stones and 1 white stone on the board thus forming opening pattern. # The second player now chooses whether to play black or white. # White then places one more stone on the board. # Black places 2 stones on the board. # White removes one of the two black stones from the previous move. # 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

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

in 2009 certified Sakata opening rule as proposed by Russia. The General Assembly of

in 2011 certified modified opening rules such as Taraguchi-N and Soosõrv-N.

Forbidden moves

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.

Winning

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).

Renju International Federation

The

(RIF) is an international organization which was founded in

Stockholm Stockholm () is the Capital city, capital and List of urban areas in Sweden by population, largest city of Sweden as well as the List of urban areas in the Nordic countries, largest urban area in Scandinavia. Approximately 980,000 people liv ...

Sweden Sweden, formally the Kingdom of Sweden,The United Nations Group of Experts on Geographical Names states that the country's formal name is the Kingdom of SwedenUNGEGN World Geographical Names, Sweden./ref> is a Nordic country located on ...

on August 8, 1988. The main purpose of the Renju International Federation is to unite all the renju and

national federations all over the world, organize international tournaments and other activities in renju and gomoku, and spread renju activities in the world. The federation carry out the General Assembly every two years.

World Championships

There are several

world championships A world championship is generally an international competition open to elite competitors from around the world, representing their nations, and winning such an event will be considered the highest or near highest achievement in the sport, game, ...

organized by the

, including World Championship, Women World Championships, Team World Championships, Youth World Championships and Correspondence World Championships. Renju World Championships have occurred every second year, since 1989. The opening rule was Yamaguchi from 2009 to 2015, and has been changed to Soosõrv-8 since 2017. The Women World Championships started in 1997 and are played every second year, at the same time and place with the World Championships. Team World Championships in Renju have occurred every second year since 1996. From 2010 to 2016, the opening rule was played is Yamaguchi, and since 2018 the rule has been changed to Soosõrv-8. World Championships in Renju via Correspondence were held in 1982 to 1993 (by paper letters, later by e-mails), and now are played every year since 1996 with an exception in 2009, 2010 and 2016.

Computers and renju

Free Renju was solved in 2001 as a win for the first player. However, renju with modern opening rules such as Yamaguchi and Soosõrv-N have not been solved. The Renju World Computer Championship was started in 1991, and held for four times until 2004. From 2016, Renju was added to the

Gomocup Gomocup is a worldwide tournament of artificial intelligences (AI) playing Gomoku and Renju. The tournament has been played since 2000 and takes place every year. As of 2016, it is the most famous and largest Gomoku AI tournament in the world, wi ...

tournament, taking place every year, still active now. The first program playing with human players in public competitions is ''Meijin-2000'' developed by Oleg Stepanov, Russia. In 2000, ''Meijin-2000'' played against human players in Moscow Open Tournament. However, not until 2017 were the computer programs proved to be able to outperform top human players in public competitions. In 2017, there was a match between the world champion program Yixin and the Taiwan's Meijin title holder Lin Shu-Hsuan, and Yixin won the match with 3-1. In 2018, there was a match between Yixin and the former world champion

Qi Guan Qi Guan (, born 4 November 1985) is a Chinese Renju ''Renju'' (Japanese: 連珠) is a professional variant of gomoku. It was named renju by Japanese journalist Ruikou Kuroiwa (黒岩涙香) on December 6, 1899 in a Japanese newspaper ''Yorozu ...

, and the match ended in a draw with 2.5-2.5.

References

External links

Renju International Federation
has complete rules and history of the game
RenjuNews
has news about Renju and Gomoku * {{Authority control Abstract strategy games Traditional board games Japanese games Solved games Games played on Go boards sv:Luffarschack#Renju