Most golf fans kind of take it for granted that a professional golf tournament -- at least on the PGA Tour, LPGA Tour and DP World Tour -- is almost always scheduled to be 72 holes, played in four rounds over four days.
But why is a golf tournament 72 holes? What made that the standard for championship golf as opposed to 18, 36 or 54 holes? Why four full rounds instead of, say, two and a half?
After all, the Open Championship -- the longest-running major and most significant golf tournament in the world -- wasn't always 72 holes. In fact, when the tournament started in 1860, it was a 36-hole affair. Three rounds were played on the 12-hole course at Prestwick to determine a winner. That was all played in a single day.
Then in 1873, the first Open was played on the Old Course at St. Andrews, which originally had 22 holes that were reduced to 18 by combining several holes together. That first Open was also 36 holes, with two 18-hole rounds played.
The first 72-hole open was played in 1892, when the Honourable Company of Edinburgh Golfers moved from Musselburgh to Muirfield. The 72-hole event was played over two days. That's when 72 holes became the standard.
Golf tournaments are 72 holes because that seemed to be the right length to properly determine the skill of the players competing in the event the magnitude of an important championship. Over a short duration, golf is a sport with a lot of variance and a variety of things beyond the players' control, including wind, other weather and course conditions. Having a tournament spread out over a long time period and with more rounds allows better players to rise to the top.
The Masters Tournament introduced the concept of a four-day golf tournament, and they took the 72 hole standard and spread it out from Thursday through Sunday. This way, golfers wouldn't get as worn out with a traditional 36-hole final day, and the club could sell more tournament round tickets. The Open went to a four-day affair in 1966.
Now, every major tour in the world -- except LIV Golf and the PGA Tour Champions -- play 72-hole tournaments.