Renju

How to play Renju

Renju is the tournament form of Five in a Row, developed in Japan around 1900. In freestyle five-in-a-row the first player has a huge advantage. Renju balances the game by giving Black a few forbidden moves.

Goal

Make an unbroken line of five stones across, down or diagonally. Black must make exactly five. White wins with five or more.

Turn by turn

1. Black plays first, and the first stone must go on the centre point of the 15×15 board.
2. Players then take turns placing one stone on any empty intersection. Stones never move.
3. When Black is to move, every forbidden point is marked with a red cross and cannot be played.

Black's forbidden moves

• Double three: one stone that makes two "open threes" at once. An open three is a line that can become an open four (four in a row with both ends free).
• Double four: one stone that makes two fours at once, even in the same line.
• Overline: six or more black stones in a row. It does not win for Black.

A move that makes an exact five always wins, even if it also creates a forbidden shape. A four plus a three (a "four-three") is allowed and is Black's main way to win. White has no restrictions at all.

End of the game

The first five ends the game. If the board fills up, it is a draw. This version uses the basic Renju rules without the professional opening and swap rules.

Strategy tips

• Black: aim for four-three. A double three is forbidden, but a four combined with an open three is legal and usually wins on the spot.
• White: use the traps. Steer Black into shapes where the only defence is a forbidden point. If Black must block on a red cross, Black cannot block at all.
• White can win with six. Overlines win for White, so don't be afraid of long lines.
• Watch the red crosses. They also show where Black's attack is "too strong" — the cross marks are often the key points of the fight.
• Block open threes early. As in all five-in-a-row games, an open four cannot be stopped, so answer open threes at once.