Page "Mahjong" Paragraph 12

Also in 1920, Joseph Park Babcock published his book Rules of Mah-Jongg, also known as the " red book ".

This was the earliest version of mahjong known in America.

Babcock had learned mahjong while living in China.

Babcock's rules simplified the game to make it easier for Americans to take up, and his version was common through the mahjong fad of the 1920s.

Later, when the 1920s fad died out, many of Babcock's simplifications were abandoned.