- H : Hold'em
- O: Omaha
- R: Razz
- S: Seven-card Stud high
- E: Seven-card stud high-low Eight or better, or hi-lo
In 2006, the World Series of Poker introduced a $50,000 buy-in H.O.R.S.E. event, and rotated games after each hour-long round, until the final table, when they switched to no-limit hold'em until the end. See pictures of that event here.