I used to play, years ago. A friend of mine used to host regular Mah Jong nights. She grew up a U. S. Foreign Service brat, and had a very nice set of tiles she bought while living in Hong Kong. As I recall, the game is very similar to gin rummy or rummy 500, but with lots of special combinations that are winning hands. A very risky game if gambling is involved – I’d rather take my chances at a blackjack table.