Renju is the professional variant of Gomoku, a Japanese board game. It is played with black and white stones on a 15x15 intersection Go board. Renju eliminates the "Perfect Win"-situation in Go-Moku by adding special conditions for the first player (Black).
Black player can win the game only by placing 5 black stones in a row (vertical, horizontal or diagonally).
White player can win by getting 5 (or more) white stones in a row, OR by forcing Black to make a Forbidden move. (Getting a double-three, a double-four or an overline. See below.)
The opening sequence differs from ordinary Go-Moku:
- The first player places 2 black and 1 white stones on the board.
- The second player now choses to play black or white.
- White then place one more stone on the board.
- Black place 2 stones on the board
- White removes one of the two black stones from the previous move..
- White place a white stone.
There are certain moves that Black is not allowed to make:
- Double three - Black can not place a stone that builds two separate lines with three black stones in unbroken rows. (Unbroken - Not stopped/blocked by white stones).
- Double four - Black can not place a stone that builds two separate lines with four black stones in a row.
- Overline - 6 or more black stones in a row.
