Japanese Mahjong (Japanese: 麻雀, 麻将 or マージャン; mājan), also known as Rīchi Mahjong, is a variation of mahjong. While the basic rules to the game are retained, the variation features a unique set of rules such as rīchi and the use of dora.
In 1924, a soldier named Saburo Hirayama brought the game to Japan. In Tokyo, he started a mahjong club, parlor, and school. In the years after, the game dramatically increased in popularity. In this process, the game itself was simplified from the Chinese version. Then later, additional rules were adopted to increase the complexity.
Mahjong, as of 2010, is the most popular table game in Japan. As of 2008, there were approximately 7.6 million mahjong players and about 8,900 mahjong parlors in the country. The parlors did 300 billion yen in sales in 2008.
In Japan, there are professional players, usually members of organizations that compete in internal leagues and external events with other professionals and the general public. There are over 1,000 professionals spread across a half-dozen organizations.