Renju is a Japanese game more popular in its homeland than abroad. Two players, black and white, place stones on a grid, attempting to form a row of five. Because the first player normally has a great advantage in such connection games, there are limitations placed on the first player's formations that do not apply to the opponent. This makes the game fairly well-balanced and suitable for serious play.
Featured in A Book of Historic Board Games
This game is featured in A Book of Historic Board Games, by Damian Gareth Walker. That volume, available as a hardback or paperback, covers twelve games in depth. For each game there is an entertaining history, full rules, and a discussion of strategy, all in more detail than you'll see on this site.
History of Renju
For many years in Japan, games have been popular in which the players strive to make a line of five of their pieces in a row. A go board and pieces were often used for this purpose. With the simplest of rules, as played exclusively until the twentieth century, black, the first player, has a distinct advantage, and so the game was not highly regarded.
Since 1900, though, interest has increased in making this attractive game playable, by introducing rules and restrictions to try and reduce black's advantage. Renju is the culmination of this process, and it achieves its aim by placing restrictions on black which do not apply to white.
Renju is now popular in Japan, though it is less so abroad. National and regional tournaments of renju take place in Japan, supporting a number of professional players. Renju may be further refined in future, and even now there are tournament rules which allow white to choose specific openings from which the rest of the game will be played.
Rules for Renju
There is considerable confusion in western books on renju, probably reflecting the fact that the game is not widely played outside Japan. The clearest account is that of David Pritchard, given in his book Brain Games, and it is his rules that are reproduced here.
1. Renju is played on the intersections of a latticed board of 15 lines by 15.
2. Two players take part, one possessing 50 black stones, the other 50 white, the board itself being empty at the start of play.
3. Black begins the game by placing a stone on the central intersection of the board.
4. White responds by placing a stone on any empty intersection he chooses. After this, play alternates between black and white, each player placing one stone until neither has stones left to place.
5. Black's subsequent moves are subject to some particular restrictions that do not apply to his opponent:
(i). he may not place a stone so as to create a row of six or more black stones;
(ii). neither can he place a stone so as to create two or more open fours. An open four is a row of four adjacent black stones, of which neither end is blocked by a white stone (see the diagram);
(iii). he may not place a stone so as to create two or more open threes. An open three is a row of three stones, with or without a gap, that may by the placement of one more stone become an open four, as described in rule 5(ii) above (see again the diagram).
(iv). It is permissible, however, to place a stone that creates simultaneously an open three and an open four.
6. A row of stones, as described in rules 5, 7 and 8, may be horizontal, vertical or diagonal.
7. Black wins the game by creating a row of five black stones.
8. White wins the game by creating a row of five or more white stones.
9. The game is drawn if, after the placement of all 100 stones, neither player has won the game.