World Series of Poker
The World Series of Poker (WSOP) is a series of poker tournaments held annually in Las Vegas and, since 2005, sponsored by Caesars Entertainment Corporation (known as Harrah's Entertainment until 2010). It dates its origins to 1970, when Benny Binion invited seven of the best-known poker players to the Horseshoe Casino for a single tournament, with a set start and stop time, and a winner determined by a secret ballot of the seven players.
1971 World Series of Poker
The 1971 World Series of Poker (WSOP) was a series of poker tournaments held at Binion's Horseshoe during May 1–15, 1971. This was only the second installment of the World Series of Poker, but unlike at the 1970 event, freezeout tournaments were played to decide the winner of the main title. The freezeout structure replaced the cash games, and it was kept in use ever since. Five freezeouts were played in total—four preliminary events and the Main Event—each featuring a different poker variant. The preliminary events required player to put up a buy-in of $1,000, while the Main Event buy-in was $5,000.