Tournament Practice Mode
Practice Gomoku under the official rules of the 全日本連珠名人戦 (All Japan Renju Meijinsen), Japan's most prestigious Renju title. Played on a 15×15 board with Black forbidden moves (禁手) — 三三, 四四, 長連 — exactly as used in the title tournament.
The 全日本連珠名人戦 (All Japan Renju Meijinsen) is Japan's oldest and most prestigious Renju title match, organized by the Japan Renju Federation. Below are the core rules used in the Meijinsen, which this practice board enforces automatically.
Played on a 15×15 grid. One player uses black stones, the other white stones. Black always moves first.
The first player to form an unbroken line of five stones horizontally, vertically, or diagonally wins. White may also win with five or more (overline allowed for White). Black must form exactly five — six or more is a forbidden move.
To balance Black's first-move advantage, Black is forbidden from creating three patterns. If Black plays a forbidden move, Black loses immediately:
Black can only win by a 四三 (Four-Three) — one four and one three from the same move.
If the entire board fills up without either player forming five in a row, the game is a draw.
Note on board history: The Meijinsen has used the 15×15 board with forbidden moves since the "New Meijinsen" era — the post-WWII reforms led by Takagawa Kakuji. Earlier editions used a 19×19 board. The core competitive rules — 15×15 board and Black forbidden moves (三三, 四四, 長連) — are what this practice board enforces.
The 全日本連珠名人戦 (All Japan Renju Meijinsen) was established in 1902, making it Japan's oldest and most prestigious Renju title. The first Meijin (名人) was 黒岩涙香 (Kuroiwa Ruikō), a journalist and poet who formalized the Renju rules to balance Black's first-move advantage.
After World War II, the tournament was reformed under the leadership of Takagawa Kakuji, who moved the game from the earlier 19×19 board to the modern 15×15 board and codified the forbidden-move rules. Takagawa himself became a legendary figure, winning the title six consecutive times, cementing the Meijinsen as the pinnacle of Japanese Renju.
The forbidden-move (禁手) rules — 三三, 四四, 長連 — are the defining feature of Renju and the heart of the Meijinsen. Because Gomoku is a solved game where Black (first player) can force a win with perfect play, the 禁手 rules are essential for fair competition. They force Black to play more carefully and strategically, preserving the depth and beauty of the game at the highest level. Today the Meijinsen has run for over 60 editions.
Black has three types of forbidden moves: 三三禁手 (double three) — creating two or more live threes in one move; 四四禁手 (double four) — creating two or more fours in one move; and 長連禁手 (overline) — forming six or more consecutive stones. If Black makes any of these moves, Black loses the game.
No. White has no forbidden moves. White can win with five, six, or more consecutive stones. The restrictions apply only to Black to compensate for the first-move advantage.
No. In the Meijinsen rules, Black can only win with exactly five consecutive stones. Six or more is a 長連禁手 (overline) and results in an immediate loss for Black. White, however, can win with five or more.
A 四三 (four-three) is the standard winning move for Black: a single stone that creates both a "four" (four consecutive stones with at least one open end) and a "three" (three consecutive stones with both ends open) at the same time. Since Black cannot use double-fours or double-threes, the four-three is Black's primary winning method.
The modern Meijinsen uses a 15×15 board, adopted during the "New Meijinsen" era after World War II under the reforms of Takagawa Kakuji. Earlier editions used a 19×19 board. This practice board uses the modern 15×15 grid with the official Black forbidden moves (三三, 四四, 長連).