List of Japanese organizations
The following is a list of organizations in Japan, pertaining to Japanese mahjong. As of October 2018, there are 1822 professionals among the Big Five organizations promoting modern riichi mahjong (not counting 101), up from about 1393 in October 2017.
| Organization | Kanji | Inception | 2017 | 2018 | 2020 |
|---|---|---|---|---|---|
| Japan Professional Mahjong League | 日本プロ麻雀連盟 | 1981 | 569 | 610 | 676 |
| Mahjong Union* | 麻将連合 | 1997 (approx.) | 53 | 70 | 74 |
| Nihon Pro Mahjong Kyoukai | 「日本プロ麻雀協会」 | 2001 (2010) | 344 | 382 | 461 |
| Real Mahjong Unit* | RMU | 2007 | 54 | 57 | 64 |
| Saikouisen Nihon Pro Mahjong | 最高位戦日本プロ麻雀協会 | 1976 | 383 | 409 | 547 |
| 101 Kyougi Renmei | 「１０１競技連盟」 | 1982 | (23) | ___ | ___ |
| ZOO |
Note: An asterisk denotes that there is a difference in member status, not all members are considered "pros".