The world’s highest profile poker tournament is under way at the Rio Hotel & Casino, with 55 championship events and a twist to its main event that will keep players in suspense until November.

The World Series of Poker started just after noon Friday with the start of a USD 10,000 pot-limit Texas Hold ’em tournament. The most expensive buy-in will be USD 50,000 for a tournament called H.O.R.S.E, where players rotate between five poker games according to a time schedule.

Seven other tournaments will cost USD 10,000 to get in, including the main event, a no-limit Texas Hold ’em tournament that likely will carry the highest prize. Last year’s winner, Jerry Yang, won USD 8.3 million. Tuan Lam of Mississauga, placed second and took home more than USD 4.8 million.

This year, the field of thousands will be whittled down by mid-July to a final table of nine, who then will take a four-month break before finishing the tournament in November.