Shuugi
Shuugi 「祝儀」 is a set payment (in money, not points) others owe when someone wins with certain "luck-based" yaku or certain types of dora. Depending on the ruleset, it may be awarded for having one or more of the following: akadora, ura dora, ippatsu, rinshan, and/or yakuman. Shuugi is almost exclusively used in gambling settings.
Shuugi is generally marked with poker chips. Each player starts with a set amount of chips (mahjong sets often come with 20 chips). When a player rons with a hand qualifying for shuugi, the ronned player pays 1 chip. When a tsumo happens with shuugi, each player pays the winner 1 chip. The chips are then exchanged for money at the end of the game.
Example
Settings: Shuugi enabled for ippatsu/ura dora/aka dora, 1 shuugi = 2000 points worth of yen.
(riichi) Winning tile: 
or 
This hand has riichi pinfu dora 1. Before shuugi, it is worth 3900 points (ron) or 5200 points (tsumo).
With shuugi:
- On ron, the hand scores 3900 points + 2000 point bonus from 1x shuugi.
- On tsumo, the hand scores 5200 points + 6000 point bonus from 3x shuugi.
If it scores 1 ura dora on top:
- On ron, the hand scores 7700 points + 4000 point bonus from 2x shuugi.
- On tsumo, the hand scores 8000 points + 12000 point bonus from 6x shuugi.
Due to shuugi being tripled on a tsumo, tsumo is heavily favored over ron.