Go

Go is an abstract strategy board game for two players who alternately place black and white stones on the intersections of a grid. The objective is to surround more territory (empty intersections) than your opponent while capturing their stones by completely enclosing them. Despite having very simple rules, Go produces extraordinary strategic complexity — it has more possible board positions than there are atoms in the observable universe. For WebPuzzle, the game is offered on reduced boards (9x9 and 13x13) to make it accessible, while preserving the core depth of the game.

Rules

1. The board is a grid of lines (traditionally 19x19, but 9x9 and 13x13 are standard for beginners). Stones are placed on the intersections, not inside the squares.
2. Black plays first. Players alternate placing one stone per turn on any empty intersection.
3. A stone or connected group of same-color stones is captured and removed from the board when all of its liberties (empty adjacent intersections) are occupied by the opponent.
4. Ko Rule: A player may not make a move that recreates the exact board position from the previous turn. This prevents infinite loops.
5. A player may pass instead of placing a stone. When both players pass consecutively, the game ends.
6. At the end, each player's score is the number of empty intersections they have enclosed (territory) plus the number of opponent stones they have captured. The player with the higher score wins.
7. Komi: To compensate for Black's advantage of moving first, White receives bonus points (typically 6.5 for a 19x19 board, 5.5 for 9x9). The half point prevents draws.

Strategies

• Territory vs. Influence: Secure territory (enclosed empty points) directly, or build influence (strong walls of stones) that can convert to territory later. Balancing these approaches is fundamental.
• Corner, Side, Center: Territory is easiest to secure in corners (two walls provided by the board edge), then along sides (one wall), and hardest in the center (no walls). Begin play in the corners.
• Life and Death: A group of stones is alive if it has two separate internal empty spaces (called "eyes") that cannot both be filled by the opponent. Learning to identify living and dead groups is essential.
• Sente and Gote: Sente means having the initiative — making moves the opponent must respond to. Keeping sente is a significant advantage; losing it to respond to the opponent (gote) is costly.
• Reading Ahead: Go requires calculating sequences of moves and counter-moves. Strong players can read 20-30 moves deep in critical positions.
• Don't Try to Save Everything: Sometimes sacrificing a few stones to gain a larger advantage elsewhere is the correct strategy. Overcommitting to saving a small group can lose the whole game.

Go originated in China over 4,000 years ago, making it the oldest board game still played in its original form. According to Chinese legend, the game was invented by the mythical Emperor Yao (around 2300 BCE) to teach his son discipline and concentration. More likely, it evolved gradually from a divination practice using black and white stones on a grid. The game was known as "Weiqi" (meaning "surrounding game") in China.

Go became one of the four essential arts of Chinese scholars, alongside calligraphy, painting, and playing the guqin. It spread to Korea (where it is called "Baduk") around the 5th century CE and to Japan (where it is called "Go" or "Igo") around the 7th century. In Japan, Go was elevated to high art under the patronage of the ruling class. The Tokugawa shogunate (1603-1868) established four official Go houses that competed for the title of Meijin (master), and the game became deeply embedded in Japanese culture.

Modern professional Go emerged in Japan in the early 20th century, with the Nihon Ki-in (Japanese Go Association) founded in 1924. Professional systems later developed in Korea and China, and by the late 20th century, Korean and Chinese players began to dominate international competition. The game has millions of active players worldwide, with professional leagues in East Asia commanding large audiences.

Go was long considered the "holy grail" of artificial intelligence because of its enormous complexity — the number of legal board positions exceeds 2×10¹⁷⁰, dwarfing Chess. Traditional game-tree search methods were inadequate. In March 2016, Google DeepMind's AlphaGo defeated Lee Sedol, one of the greatest Go players in history, 4 games to 1. This was widely considered one of the most significant achievements in AI history. The subsequent version, AlphaGo Zero, learned to play from scratch (without any human games) and surpassed all previous versions. This breakthrough demonstrated the power of deep reinforcement learning and fundamentally changed the field of AI research.

For beginners, 9x9 and 13x13 boards are recommended starting points. A 9x9 game takes 10-15 minutes and teaches the fundamentals of capturing, life and death, and territory. A 13x13 game introduces more complex strategic concepts while remaining manageable. Many players progress to the full 19x19 board after gaining confidence on smaller sizes.