6. Variants & House Rules
Board Sizes
- 13x13 and 9x9 are the common smaller boards, standard for teaching and fast games (AGA Rule 1)
- On boards smaller than 19x19 a non-integral komi should still be used, since avoiding a drawn game is part of the spirit of the AGA rules
Other Rule Sets
- Japanese rules use territory scoring and treat ko and life-and-death differently in rare positions
- Chinese rules use area scoring and a different komi convention
- The differences change the result only in unusual endgames, but tournaments always announce which rule set applies
Common Tournament Conventions
- Handicap stones let players of different ranks meet on even terms — one stone per rank difference is the usual guide
- Timed games use byo-yomi (reserve periods) or Fischer increment; time is a tournament regulation, not part of the rules of play