The rules of Go, simply

1. Place a stone, one at a time

Go is played on a grid board: 19 × 19 lines for a full game, 9 × 9 or 13 × 13 to start. Black plays first, then Black and White take turns placing one stone on an empty point. Once placed, a stone never moves. Instead of playing, you may also pass.

2. Liberties

A stone’s liberties are the empty points right next to it: up, down, left, right (not diagonally). In the middle of the board, a lone stone has 4; on the edge, 3; in the corner, 2.

Stones of the same color that touch form a group. They share their liberties: they live and die together.

3. Capture and atari

When a group has no liberties left, it is captured: its stones are removed from the board and become prisoners. When it has only one liberty left, it is in atari: save it, or accept losing it.

You can’t place a stone where it would have no liberties (that’s suicide), unless the move captures enemy stones: they are removed first, and your stone gets liberties back.

4. Ko

Sometimes a stone captures a single stone and could be taken back at once by the same move the other way round. Without a rule, both players would go round in circles. Ko forbids it: after such a capture, the other player must play elsewhere first. On the next turn, they may take back.

5. End of the game and scoring

When there is nothing useful left to play, each player passes. Two passes in a row end the game. Dead stones (those that can no longer escape capture) are removed, then you count:

• your territory: the empty points surrounded only by your stones;
• plus your prisoners: the stones you captured.

White gets komi, usually 6.5 points, because Black played first; the half point avoids ties. The higher total wins. These are Japanese rules, the ones Mochi Go uses. Chinese rules count territory plus stones on the board, with 7.5 komi: the winner is almost always the same.