The Walker Cup is a golf trophy contested in odd-numbered years by leading amateur golfers in two teams: United States, and Great Britain and Ireland. The official name is the Walker Cup Match (not "Matches" as in Ryder Cup Matches). It is organised by The R&A and the United States Golf Association (USGA). In 1921 the Royal Liverpool Golf Club hosted an unofficial contest which was followed by official annual contests from 1922 through 1924. From 1925 they became biennial, held on even-number years. After World War II they switched to odd-numbered years. They are held alternately in the U.S., and Ireland or Britain.