Toutenkou
Toutenkou 「東天紅」 is a special 3-player mahjong variation mainly popular in Kanto region. Currently available in Tenhou computer matches.
Rule Introduction
Only uses 
of manzu tiles, while all of pinzu, souzu and honor tiles are used (including red fives 
). 112 tiles in total.
are kari 「カリ」, similar to nukidora. 20 rinshan tiles in total.
A valid winning hand must include at least one of any regular yakus (identical to regular riichi mahjong yakus). A hand cannot win with only special yakus.
Instead of calculating with fu and han, the score is only counted with points.
Ron takes points from only one opponent (with 8 more extra points than tsumo).
Tsumo takes points from two opponents.
Special Yakus
References
External Links
- Toutenkou in Japanese Wikipedia