Hoshokin

Everytime a rikishi does something good
(kachikoshi , for example) he gets an additional bonus to his salary paid after every hon-basho . For a rikishi starting out in Jonokuchi , this starts
out as 3 yen, but gets 50 sen added to it every win over kachikoshi he makes. So, for example, a Jonokuchi rikishi gets his first kachikoshi at a score of 5-2, he gets 1 yen added to his 3 for a total of 4.

Now, once a rikishi gets to Juryo , this rate is increased a uniform 50 yen.
Makuuchi rikishi get 60 yen. Ozeki  get 100 yen, and Yokozuna get 500 yen.
Every kinboshi adds 10 yen to this rate, a Makuuchi yusho adds 30 yen, and a zensho-yusho adds 50 yen. To put it in career perspective, Taiho set the record at 1449 yen. This does not seem like much, but , this gets multiplied by 2,500. So a kinboshi is really worth 25,000 yen, rather than 10 yen. This is always added to the rikishi's base salary.

(Thanks to Josh Reyer for this information)