By 1975, the concept of the modern majors had been firmly established, and the PGA Championship had been moved to August since 1969, so no longer clashed with the Open. This meant the Open had a feel similar to the current tournament, with the leaders after 36 holes going off last (1957 onwards), all players having to use the "bigger ball" (1974 onwards), play spread over four days (1966 onwards, although the days were Wednesday to Saturday until 1980), and a field containing all the world's best players.