Go’s 19-by-19 grid is older than most kingdoms
Go—also Weiqi or Baduk—is a two-player abstract game of fencing off territory with stones. Invented in China more than 2,500 years ago, it was one of four arts expected of scholarly gentlemen; the Zuo Zhuan (c. 4th century BC) offers an early written nod.
Players take turns putting black or white stones on the empty intersections of the board. Stones never move once placed, but a stone or connected group is captured and removed when the opponent occupies every orthogonally adjacent point. At the finish each side counts surrounded territory and captures, and White receives komi as compensation for moving second; games may also end by resignation.
Survival hinges on eyes. A group with two or more enclosed empty points can never be captured, because filling either eye would be suicide, which is banned. Groups that cannot make two eyes are dead, capturing races are called semeai, and mutually alive groups without two eyes are in seki. The ko rule forbids recreating a previous board position, so a player whose stone was just taken must play elsewhere before retaking. Openings usually begin near the corners on the third or fourth line, and standard corner sequences are called joseki.
Simple rules hide staggering complexity: about 2.1×10^170 legal positions exist, far more than the roughly 10^80 atoms in the observable universe. Ranks climb from 30 kyu to 1 kyu, then through amateur dan grades to 9 dan professional, and weaker players may receive handicap stones.
Beginners often use 9×9 or 13×13 boards, and archaeology shows a 17×17 grid in earlier centuries; the full 19×19 grid was already the norm when Korea adopted the game around the 5th century CE, two centuries before Japan did. The English name comes from Japanese igo, from Middle Chinese words for an encirclement board game, while Korean baduk probably combines words for field and stone. A 2016 International Go Federation survey found over 46 million people who know the game and more than 20 million active players, mostly in East Asia.
Source: Go (game)
