The World Series of Poker (WSOP) is a series of poker tournaments^[1] held annually in Las Vegas and, since 2005, sponsored byHarrah’s Entertainment. It dates its origins to 1970, when Benny Binion invited seven of the best-known poker players to theHorseshoe Casino for a single tournament, with a set start and stop time, and a winner determined by secret ballot.^[2]

The winner of each event receives a World Series of Poker bracelet and a monetary prize based on the number of entrants and buy-in amounts. Over the years, the tournament has grown in both the number of events and in the number of participants. Each year, the WSOP culminates with the $10,000 no-limit hold’em „Main Event“, which since 2004 has attracted entrants numbering in the thousands. The victor receives a multi-million dollar prize and a bracelet, which has become the most coveted award a poker player can win.^[3]The winner of the World Series of Poker Main Event is considered to be the World Champion of Poker.^[4]

Starting in 2011, the WSOP consists of 58 events, with most major poker variants featured, though in recent years over half of the events have been variants of Texas hold ‚em. Events traditionally take place during one day or over several consecutive days during the series in June and July. However, starting in 2008, the Main Event final table was delayed until November. Due to the 2012 U.S. Presidential Election, the 2012 WSOP final table will be delayed until October 28.

Since 1971, all WSOP events have been tournaments with cash prizes. In 1973 a five-card stud event was added. Since then, new events have been added and removed. Since 1976, a bracelet has been awarded to the winner of every event at the annual WSOP; later on,^[when?] the winners of pre-1976 events were retroactively given bracelets.

The tournament grew slowly for over a decade, reaching 52 participants in 1982.^[1] In the early 1980s, satellite tournaments were introduced, allowing people to win their way into the various events.^[1] By 1987, there were over 2,100 entrants in the entire series.^[1]

At the 2006 World Series of Poker, there were 45 events, covering the majority of poker variants. Participation in the Main Event peaked that year, with 8,773 players competing.^[5]

Currently, Texas hold ‚em, Omaha hold ‚em and Seven-card stud and their lowball variants are played. H.O.R.S.E. has been played in the past and returned in 2006. Also, S.H.O.E. has been played in the past, and returned in 2007. Other events played in the past include Chinese poker, Five card stud, and many others. Like most tournaments, the sponsoring casino takes an entry fee (a percentage between 6% and 10%, depending on thebuy-in) and distributes the rest, hence the prize money increasing with more players. In the 2005 Main Event, US$52,818,610 in prize money was distributed among 560 players, with US$7.5 million as the first prize. The 2006 Main Event, won by Jamie Gold, is the largest single poker tournament in history; Gold pocketed US$12 million for his victory. In July 2010, it was announced that the winner of the 2010 Main Event would receive just under US$9 million.

On June 2, 2011, the World Series of Poker and Cirque du Soleil founder Guy Laliberté announced plans for an officially sanctioned special fundraising event, officially known as The Big One for One Drop, on June 1, 2012 with a record US$1 million entry fee.^[6] 11% of the money would go to Laliberté’s charity, the One Drop Foundation, and the WSOP will waive its normal 10% rake of the entry fees. At the time of the announcement, 15 of the maximum 48 seats had been taken. By early December 2011, the field size had increased to 22, the minimum required for an official bracelet tournament.^[7] Among those who have committed to the event are Johnny Chan, Daniel Negreanu, Jonathan Duhamel,Tom Dwan and billionaire businessman Phil Ruffin. If at least 29 players sign up, the first prize will exceed the record amount won by Jamie Gold. In addition, a WSOP bracelet will be awarded.