What's the difference between American Mah Jongg in Chinese Mah Jongg?

The main difference is that the hands allowed in American Mah Jongg are listed on a card and these hands change on a regular basis, usually annually. The allowed hands in Chinese Mahjong never change. Another key difference is The Charleston in American Mah Jongg (an exchange of tiles at the beginning of the game). Finally, a Chinese Mahjong set includes 144 tiles, whereas an American set includes 152 (with the inclusion of 8 joker tiles).