Renju

Renju is played on a 15x15 gridded board. The playing pieces, called stones, are played on the grid line intersections.
Genre(s)	Board game Abstract strategy game
Players	2
Age range	5+
Playing time	Casual games: 5 to 30 minutes; tournament games: from 10 minutes (renju blitz) to 5 hours or longer
Random chance	None
Skill(s) required	Strategy, tactics

Renju (Japanese: 連珠) is the professional variant of Gomoku, a strategy board game originating in Japan from the Heian period. 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 game is played with black and white stones on a 15x15 gridded Go board.

Renju eliminates the "Perfect Win" situation in Gomoku by adding special conditions for the first player (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 RIF General Assembly 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") follows.

1. The first player places 2 black stones and 1 white stone on the board thus forming opening pattern.
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 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 Renju International Federation in 2009 certified Sakata opening rule as proposed by Russia. The General Assembly of Renju International Federation in 2011 certified modified opening rules such as Taraguchi-N and Soosõrv-N.

Disallowed 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).

World championships

World Championships in Renju have occurred every second year, since 1989. Since 2009 the opening rule being played is Yamaguchi.

Previous World Championships have taken place in the following places:

Title year	Hosting city, country	Champion	Opening rule
1989	Kyoto Japan	Shigeru Nakamura	Swap opening rule
1991	Moscow USSR	Shigeru Nakamura	Swap opening rule
1993	Arjeplog Sweden	Ando Meritee	Swap opening rule
1995	Tallinn Estonia	Norihiko Kawamura	Swap opening rule
1997	Saint Petersburg Russia	Kazuto Hasegawa	RIF opening rule
1999	Beijing China	Ando Meritee	RIF opening rule
2001	Kyoto Japan	Ando Meritee	RIF opening rule
2003	Kyoto Sweden	Tunnet Taimla	RIF opening rule
2005	Tallinn Estonia	Ando Meritee	RIF opening rule
2007	Tyumen Russia	Wu Di	RIF opening rule
2009	Pardubice Czech Republic	Vladimir Sushkov	Yamaguchi opening rule
2011	Huskvarna Sweden	Cao Dong	Yamaguchi opening rule
2013	Tallinn Estonia	Tunnet Taimla	Yamaguchi opening rule
2015	Suzdal Russia	Qi Guan	Yamaguchi opening rule

Team World championships

Team World Championships in Renju have occurred every second year, since 1996. Since 2010 the opening rule being played is Yamaguchi. The results are following.

Title year	Hosting city, country	Champion team
1996	Saint-Petersburg Russia	Russia (Ilyin D., Peskov S., Sinyov I., Nikonov K., Kozhin M.)
2000	Tallinn Estonia	Russia (Sinyov I., Klimashin A., Sushkov V., Salnikov P., Kozhin M.)
2002	Vadstena Sweden	Russia (Salnikov P., Klimashin A., Artemyev S., Skouridin A., Semyonov V.)
2004	Tyumen Russia	Russia(Sushkov V., Klimashin A., Chingin K., Nikonov K., Sinyov I.)
2006	Tallinn Estonia	Russia (Sushkov V., Chingin K., Artemyev S., Savrasova Yu., Vershinin P.)
2008	Helsinki Finland	Estonia (Taimla T., Oll A., Purk A., Soosorv A., Lents J.)
2010	Tokyo Japan	China (Li Yi, Cao Dong, Yin Licheng, Xi Zhenyang)
2012	Beijing China	Japan (Yuuki Oosumi, Shigeru Nakamura, Takahiro Kudomi, Kazumasa Tamura, Hiroshi Okabe, Tomoharu Nakayama)
2014	Taipei Taiwan, Republic of China	Estonia (Tunnet Taimla, Martin Hobemagi, Ants Soosorv, Johann Lents, Ando Meritee)

Renju World Championships via Correspondence

World Championships in Renju via Correspondence were held in 1982, 1984, 1985 (by paper letters, later by e-mails) and now are played every year since 1996 with an exception in 2009, 2010. Since 2014 the opening rule being played is Soosõrv-7. The results follow.

Title year	Champion	Country
1982	Sapronov, Vladimir	USSR
1984	Nosovsky, Alexander	USSR
1985	Nosovsky, Alexander	USSR
1996	Reims, Aldis	Latvia
1997	Tarannikov, Yuri	Russia
1998	Fedorkin, Oleg	Russia
1999	Fedorkin, Oleg	Russia
2000	Reims, Aldis	Latvia
2001	Nikonov, Konstantin	Russia
2002	Lunkin, Vitaly	Russia
2003	Chen Wei	China
2004	Sun Chengmin	China
2005	Barykin, Victor	Russia
2006	No gold awarded	Silver: Epifanov, Dmitry., bronze: Barykin, Victor
2007	Epifanov, Dmitry	Russia
2008	Zhang Jinyu	China
2011	Balanova, Jelena	Latvia
2012	Potapov, Alexey	Russia
2013	Sushkov, Vladimir	Russia
2014	Sushkov, Vladimir	Russia

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