The Louis Vuitton Cup was the name of the Challenger Selection Series sailing competition from 1983, named after its sponsor, Louis Vuitton. The winner of the competition became the challenger to compete with the defender of the America's Cup. The competition for the 2017 America's Cup changed format and name to the Louis Vuitton Challenger’s Trophy. The following series, in 2021, was named the Prada Cup after its new sponsor. Five out of the nine winners of the Louis Vuitton Cup competitions subsequently won the America's Cup itself. History In 1970, for the first time in America's Cup history, multiple "international" challengers competed for the right to challenge the New York Yacht Club, the defender of the America's Cup (the key word being "international": in 1964, for example, two British challengers competed for the right to challenge the NYYC.) For the 1983 America's Cup match, the Royal Sydney Yacht Squadron, the "Challenger of Record", contracted with New York Yacht Club member, Paul Madden, to create "The Challenger's Cup". Paul Madden then contracted with Louis Vuitton to be the first sponsor of this Cup series that led up to the main event. Louis Vuitton offered a trophy to the winner of the challenger selection series; the idea was Paul Madden's, but is generally credited to Bruno Trouble, a French yachtsman. The initial Louis Vuitton Cup was contested off Newport, United States, with Australia II prevailing, thereby earning the right to meet the NYYC’s defending yacht Liberty in that year’s America’s Cup. With the exception of the America's Cup races in 1988 and 2010, the winner of the Louis Vuitton Cup has been awarded the right to challenge the current defender for the America's Cup. During the 1992 and 1995 regattas Citizen Watch offered a trophy to the winner of the defender selection series (the Citizen Cup) as the defense’s counterpart to the Louis Vuitton cup. Due to the large number of challengers in recent decades the Louis Vuitton Cup has had to eliminate challengers in two phases. A round-robin points accruing phase, and then a pair of semi-finals involving the top four, followed by a final between the top two. The semi-finals and finals are a best of nine races between two boats. Between the 2004 and 2007 Cups, Louis Vuitton sponsored thirteen "acts" of competition, with the first three acts not awarding points toward rankings. Some challengers do not enter