Different histories
Mahjong spread quickly and without a central authority. Each community developed scoring to suit its own stakes and preferences. Gambling traditions favoured rapid doubling; competition rules favoured detailed point lists; American players chose a card with fixed values.
Shared principles
Despite the differences, all systems reward the same things: harder hands, concealed hands, honour sets, one-suit hands and lucky wins such as self-draws. A thirteen orphans hand is spectacular everywhere.
Simplicity versus nuance
Simple systems are easy for beginners and fast at the table; complex systems reward knowledge and planning. Neither is better — they produce different games.
A practical rule
Before the first tile is drawn, agree which system you are using, the minimum to win and the limit. Writing the agreement down saves arguments later.
