Renju 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 chouhou (萬朝報). The name "renju" means "connected pearls" in Japanese. The game is played with black and white stones on a 15×15 gridded go board.
Renju is played on a 15×15 gridded board. The playing pieces, called stones, are played on the grid line intersections.
Gomoku, also called Five in a Row, is an abstract strategy board game. It is traditionally played with Go pieces on a 15×15 Go board while in the past a 19×19 board was standard. Because pieces are typically not moved or removed from the board, gomoku may also be played as a paper-and-pencil game. The game is known in several countries under different names.
Gomoku
Pro Opening Rule: Black places first stone in the center of board. White can place anywhere, but places to the South-East. Black places their second stone three spaces away.
Swap Opening Rule: Tentative Black places two black stones and one white stone anywhere on the board. Tentative white chooses which color to play as.
Swap2 Opening Rule: Tentative Black places two black stones and one white stone anywhere on the board. Tentative White responds by picking option number three and placing two more stones, one of each color, on the board and passes the choice of which color to play as to tentative Black.