Count up all the Han and Fu that the hand should score, then calculate the payment(s) that should be made. Remember that you don't have to count Fu when there is at least 5 Han.
Only use the Yakuman check box for "automatic" Yakuman like Kokushi Musou.
Check "More small hands" if you want more hands with low Han values.
Open Riichi is treated as 2 han if won by Tsumo, Yakuman if won by Ron.
Dai Sha Rin is a Yakuman consisting of 22334455667788 Pin.
Double yakuman are as follows:
四暗刻単騎/Suu an kou tanki wait
国士無双13面/Kokushi musou 13-sided wait
大四喜/Dai suu shi
純正九蓮宝燈/Junsei chuu ren pou tou
Please report any errors or bugs to UmaiKeiki in #mahjong.