Renju

Renju is the professional version of Gomoku, with special rules added to balance the strong first-player advantage. Black has restrictions on certain winning patterns, making the game more competitive and strategic at high levels.

Get exactly five stones in a row horizontally, vertically, or diagonally. Black must avoid making forbidden patterns.

Played on a 15x15 Go board. The board starts empty. Black plays first and places the first stone at the center intersection.

1. Players alternate turns placing one stone on any empty intersection.
2. Five consecutive stones in a line (horizontal, vertical, or diagonal) wins.
3. White can win with five OR MORE stones in a row (overline is legal for White).
4. Black must win with EXACTLY five stones - an overline (6+) is forbidden and loses.
5. Black cannot make a 'double four' (two separate open fours simultaneously) - this is forbidden and loses.
6. Black cannot make a 'double three' (two separate open threes simultaneously) - forbidden and loses.
7. If Black creates a forbidden pattern, they lose immediately.
8. White has no restrictions and can freely create double patterns.
9. Professional rules include swap and swap2 opening procedures for balance.

Create exactly five stones in a row (Black) or five or more (White). Black immediately loses if they make a forbidden pattern.

• *As Black, be extremely careful about double threats - they might be forbidden.
• *As White, use Black's restrictions against them by forcing positions.
• *An overline threat can be a defensive tool for White - Black cannot complete it.
• *Learn the forbidden patterns thoroughly before playing seriously.
• *The opening moves are crucial - professional study of opening theory helps.
• *Look for complex forcing sequences that don't involve forbidden moves.
• *Sometimes a single threat is better than a double threat for Black.

Renju was developed in Japan in the early 20th century to balance Gomoku's first-player advantage. It is governed by the Renju International Federation, which organizes world championships.