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 2nd 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. 5 freezeouts were played in total—4 preliminary events and the Main Event—each featuring a different poker variant. The preliminary events required player to put up a buy-in of $1K, while the Main Event buy-in was $5K.