Golf is an outdoor precision ball sport, in which players use a variety of clubs to propel a ball along the course and into a series of holes, with the object of completing the course in the fewest possible strokes. The modern game emerged in Scotland in the 15th century, borrowing from elements of older games from disparate regions.
The ball was originally a smooth wooden sphere, with more expensive balls composed of feathers stuffed into a shrunken leather spherical pouch (called a "featherie"). This evolved through the centuries, with many advancements coming in the 1900s with novel materials and designs. The modern golf ball is composed of varying layers of synthetic materials, selected and designed for various qualities such as compression/hardness (a harder ball travels further but has less lift-inducing backspin), durability, spin control and "feel".
Clubs originally had metal heads attached to wooden shafts with wrapped leather grips. Over time, the shape of the clubheads evolved to perform different tasks such as long-distance shots, high-lofted shots, and short rolling shots. The design of clubs became more and more standardized by tradition and rules definitions, and today comprise four major classes: woods, typically used for long-distance shots from the tee or turf; irons, used for a variety of shots from many places on the course, and the putter, a specialized club for rolling the ball along the putting green and into the hole. A new class, hybrids, was developed in the late 1990s as a cross between woods and irons as an answer to the difficult to hit "long irons". "Wedges" are a subclass of irons typically differentiated by very high loft angles of the clubface (48 degrees or more), used for a variety of "utility" shots such as escaping from hazards, hitting onto the green from close range and other tricky situations. The modern club typically has a hollow steel or carbon-fiber ("graphite") shaft, and a molded rubber or composite synthetic grip.
A "round" of play typically consists of 18 "holes" (a course may have 9 holes and players play each one twice, or may have more than 18 which can be rotated or substituted for maintenance or variability reasons). Each hole consists of four major parts: the "tee box" is the starting point at which all players make their first shot. The "fairway" is an area of relatively close-cut, well-maintained grass turf which is advantageous to play from, and which players attempt to play onto as they move "through the green" toward the hole. The fairway is surrounded on its edges by "rough", taller grass which impedes the club's impact with the ball and is more difficult to hit from with accuracy and distance. At the end of each hole is the "putting green" or simply the "green", which has the actual "hole" or "cup" and a "flagstick" indicating the hole's position from a distance. Also common on most holes is one or more "hazards", such as sand-filled pits called "bunkers", or streams or ponds which are "water hazards". A hole is rated according to how many strokes should be necessary to place the ball in the hole, with all holes given a minimum of one "tee shot" and two "putts"; this rating is called the hole's "par", and most holes are rated as a par-3, par-4 or par-5. A few par-6 and a couple of par-7 holes exist, but these are rare; the distances required to necessitate 7 strokes is quite long (880+ yards), and pure distance as the primary obstacle can actually reduce the difficulty of the course for "scratch golfers" while drastically increasing it for the casual amateur, so instead course designers seek to add features such as terrain variations and hazards to increase difficulty at all skill levels. The total par rating of all holes of a course is known as the "course par", and most courses are a par-72, but courses with a lower par (as low as 68) are common as well.
The three main rules of golf are: "play the ball as it lies, play the course as you find it, and if you can do neither, do what is fair". More specific rules comprise the full "Rules of Golf", primarily expanding on what is "fair" in various common situations, typically prescribing "penalties" in exchange for "relief" from particularly disadvantageous situations. In the U.S., the rules of play, strictly enforced at sanctioned events, are set by the governing body, the United States Golf Association or USGA. The main international governing body for golf is the R&A, originally the Royal and Ancient Golf Club of St Andrews, but the rulemaking body has since become separate from the actual golf club of St Andrews. Most national golf associations including the USGA generally base their rules on those of the R&A, but there have been notable variations between the USGA and R&A rulesets over the years.
Golf is played at almost every level of age and skill, with serviceable club sets available for children as young as 3 as well as for senior citizens or the handicapped, and nearly infinite levels of customization available to tailor a set of clubs to a player's height, posture, swing speed, and other age- and skill-related factors. The overwhelming majority of players are "casual amateurs", playing recreationally for fun and challenge. A small percentage make money teaching the game, with a very select few "touring professionals" playing in major sanctioned tournaments for prize money and corporate sponsorship. The game was an Olympic sport in the 1900 and 1904 Games, but was discontinued for over 100 years until it was announced that the 2016 Games in Rio de Janeiro would feature golf as an event.
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