The Open is a 72-hole stroke play tournament contested over four days, Thursday through Sunday. Since 1979 it has been played in the week which includes the 3rd Friday in July. Currently, 156 players are in the field, mostly made up of the world's leading professionals, who are given exemptions, along with winners of the top amateur championships. Further places are given to players, amateurs and professionals, who are successful in a number of qualifying events. There is a cut after 36 holes after which only the leading 70 players (and ties) play in the final 36 holes on the weekend. In the event of a tie after 72 holes, a four-hole aggregate playoff is held; if two or more players are still tied, it continues as sudden-death until there is a winner.
Timeline of format changes[edit] 1860: Contested over 36 holes, played on a single day 1892: Extended to 72 holes, played over two days 1898: Cut introduced after 36 holes. Those 20 or more strokes behind the leader were excluded 1904: Extended to a third day with 18 holes on each of the first two days. Cut rule unchanged 1905: Cut rule changed to exclude those 15 or more strokes behind the leader 1907: Qualifying introduced, replacing the 36-hole cut and the contest reduced again to two days 1910: Cut reintroduced instead of qualifying, play being extended to three days again. Top 60 and ties made the cut. 1911: With an increase in the number of entries, the first two rounds were spread over three days, with 36 holes on the fourth day 1912: Qualifying reintroduced to replace the cut. Contest reduced again to two days 1926: Cut reintroduced. First Open with both qualifying and a cut. Extended again to a third day with 18 holes on the first two days. Those 15 or more strokes behind the leader were excluded from the final day. Days standardised as Wednesday to Friday 1929: Cut rule changed to ensure that at least 60 made the cut even if 15 or more strokes behind the leader 1930: Cut rule changed to top 60 and ties 1937: Cut rule changed to top 40 and ties 1938: Cut rule changed to be a maximum of 40 players. Ties for 40th place did not make the cut 1939: Cut rule changed to be a maximum of 44 players. Ties for 44th place did not make the cut 1946: Cut rule changed to be a maximum of 40 players. Ties for 40th place did not make the cut 1951: Cut rule changed to be a maximum of 50 players. Ties for 50th place did not make the cut 1957: Leaders after 36 holes go off last, replacing the random draw 1963: Cut rule changed to top 45 and ties 1964: Playoff reduced from 36 holes to 18, followed by sudden-death if still level 1966: Play extended to four days, 18 holes per day from Wednesday to Saturday. Cut rule changed to top 55 and ties 1968: Cut rule changed to top 70 and ties after 36 holes and then top 45 and ties after 54 holes 1970: Cut rule changed to top 80 and ties after 36 holes and then top 55 and ties after 54 holes 1971: Cut rule changed to top 80 and ties after 36 holes and then top 60 and ties after 54 holes 1973: Play in groups of three introduced for the first two rounds 1974: Use of "bigger ball" (1.68 in, 42.67 mm) made compulsory 1978: "10-shot rule" introduced so that players within 10 shots of the leader make the cut even if outside the top 80/60 1980: Play from Thursday to Sunday 1986: 54-hole cut discontinued. Cut rule changed to top 70 and ties after 36 holes. Four-hole playoff introduced 1996: "10-shot rule" dropped