Rules of golf
The rules of golf consist of a standard set of regulations and procedures by which the sport of golf should be played and prescribe penalties for rule infractions. They are jointly written and administered by the R&A (spun off from The Royal and Ancient Golf Club of St Andrews) the governing body of golf worldwide except in the United States and Mexico, which are the responsibility of the United States Golf Association (USGA). The rule book, entitled Rules of Golf, is published on a regular basis and also includes rules governing amateur status.
A central principle, although not one of the numbered rules, is found in the R&A rule book's inside front cover: "Play the ball as it lies, play the course as you find it, and if you cannot do either, do what is fair. But to do what is fair, you need to know the Rules of Golf."
In addition to the rules golf adheres to a code of conduct, known as etiquette, which generally means playing the game with due respect for the golf course and other players. Etiquette is often seen as being as important to the sport as the rules themselves.
Before the rules of golf were standardised golf clubs commonly had their own set of rules, which while broadly the same had subtle differences, such as allowing for the removal of loose impediments, e.g. leaves and small stones. In the late 19th century, most clubs began to align themselves with either the Society of St. Andrews Golfers, later the R&A, or the Gentlemen Golfers of Leith, later the Honourable Company of Edinburgh Golfers.
The earliest surviving written rules of golf were produced by the Gentlemen Golfers of Leith on 7 March 1744, for a tournament played on 2 April. They were entitled "Articles and Laws in Playing at Golf" and consisted of 13 rules.
- You must Tee your Ball within a Club's length of the Hole.
- Your Tee must be upon the Ground.
- You are not to change the Ball which you Strike off the Tee.
- You are not to remove Stones, Bones or any Break Club, for the sake of playing your Ball, Except upon the fair Green within a Club's length of your Ball.
- If your Ball comes among water, or any watery filth, you are at liberty to take out your Ball & bringing it behind the hazard and Teeing it, you may play it with any Club and allow your Adversary a Stroke for so getting out your Ball.
- If your Balls be found any where touching one another, You are to lift the first Ball, till you play the last.
- At Holing, you are to play your Ball honestly for the Hole, and not to play upon your Adversary’s Ball, not lying in your way to.
- If you should lose your Ball, by its being taken up, or any other way, you are to go back to the Spot, where you struck last, & drop another Ball, And allow your adversary a Stroke for the misfortune.
- No man at Holing his Ball, is to be allowed, to mark his way to the Hole with his Club, or anything else.
- If a Ball be stopp’d by any Person, Horse, Dog or anything else, The Ball so stop’d must be play’d where it lies.
- If you draw your Club in Order to Strike, & proceed so far in the Stroke as to be bringing down your Club; If then, your Club shall break, in any way, it is to be Accounted a Stroke.
- He whose Ball lies farthest from the Hole is obliged to play first.
- Neither Trench, Ditch or Dyke, made for the preservation of the Links, nor the Scholar's Holes, or the Soldier's Lines, Shall be accounted a Hazard; But the Ball is to be taken out and play’d with any Iron Club.
Debate surrounds the authorship of these regulations, which were signed by John Rattray and which—on matters of order of play, outside interference, water hazards, holing out, making a stroke, and the stroke and distance penalty for the loss of a ball—remain an integral part of the modern game. Rattray's sole signature does not guarantee that he was wholly responsible for them, though his prominence within the company and Edinburgh society at large makes him the most likely candidate. Under these rules he went on to win the silver club for a second time in April 1745.
Rules of Golf (book) 
The Rules of Golf and the Rules of Amateur Status is published every four years by the governing bodies of golf (R&A/USGA) to define how the game is to be played.  The Rules have been published jointly in this manner since 1952, although the code was not completely uniform until 2000 (with mostly minor revisions to Appendix I). Before 2012 the USGA and R&A presented the same content differently in separate editions. The same content is now published in a uniform fashion with similar formatting and covers — the only differences are now some spelling and their logos. The Rules Committee of The R&A, which was spun off from The Royal and Ancient Golf Club of St Andrews in 2004, has responsibility for upkeep and application of the rules worldwide except in the United States and Mexico, which are the responsibility of the United States Golf Association (USGA).
The term "Rules" can be said to include the following:
- Decisions on the Rules of Golf, a book published every two years by the USGA and R&A to clarify questions raised by the Rules.
- Local rules set by the Committee of a golf club, for example to denote the method used to define the boundaries of the course, ball drops, environmentally sensitive areas (ESAs), etc.
- Rules of golf etiquette, covered by the main book, define the proper behaviour of those playing the game.
- Rules often adopted in competitions, for example the prohibition on using automotive transportation during a round and Rules related to Temporary Immovable Obstructions (TIOs).
- Rules governing the size, shape and performance of golf equipment (clubs and balls) as defined by the R&A/USGA (Appendices I and II).
- Rules governing golfers with disabilities who play in accordance with A Modification of the Rules of Golf for Golfers with Disabilities as published by the R&A and USGA.
The Royal and Ancient Golf Club of St Andrews is a private golf club run for the benefit of its members. As such, since 2004 it has passed responsibility of publishing the rules to a private company, R&A Rules Ltd, operating under the stewardship of the golf club.
In 2004, the University of Chicago Press published a plain-language translation of this book. It was entitled The Rules of Golf in Plain English, by the lexicographer Bryan A. Garner and USGA rules official Jeffrey S. Kuhn. The purpose was to make the rules more accessible than the official version, which is pervasively legalistic and opaque.
The Rules of Golf book includes a section on proper etiquette, defining recommendations that make the game safe, enjoyable and fair for all players. While none of these guidelines are enforced by penalty in and of themselves, the course authorities or other local "committee" may, under Rule 33-7, disqualify any player who acts in serious breach of etiquette, thereby violating the "spirit of the game". Such serious breaches include actions made with intent to damage the course, facilities or other players' equipment, to injure other players or disturb/distract them while making their play, to unreasonably hold up or delay other players from continuing their game, or to use any of the Rules or Decisions for the purpose of gaining an unfair advantage over any other player.
The rulebook also include definitions of terms used throughout the rulebook (sometimes including examples of what does or does not meet a definition), and defines the use of particular words in context to clarify what is meant by the use of a word. The rules, for instance, differentiate between use of "a" and "the" referring to objects involved in play ("a ball" refers to any ball that can be used in a situation; "the ball" specifically refers to the ball previously mentioned in the Rule), or between "may" (discretionary), "should" (non-binding recommendation) and "must" (binding requirement). Where used in the Rules, the definitions of the terms are binding and must be strictly observed; players must not use a differing definition in order to include or exclude on object involved in play from a particular Rule governing the object.
Rule summary 
The numbered Rules each define a relatively large part of the game; more specific instructions are given as "sub-rules". The following is a simplified version of the 2012 USGA Rules of Golf (published jointly by the USGA and R&A as of 2012 with spelling and logo differences):
- Rule 1 – Game
- 1-1 – Defines the game of golf in general as playing a ball with clubs into holes according to the rules.
- 1-2 – In general, players must not influence the position or movement of any ball in play nor alter the course itself, unless specifically allowed by another rule, or in the general interest of preserving the course from damage. Violation is a two-stroke penalty in stroke play or loss of the hole in match play.
- 1-3 – The rules are to be strictly observed in their entirety; players must not agree to change or waive any of them under penalty of disqualification.
- 1-4 – Any dispute as to the proper action which is not covered by the Rules should be resolved by doing what is most equitable.
- Rule 2 – Match play
- 2-1 – Defines "match play" as a variant where players compete for the lowest score on each hole, and defines terms used during play.
- 2-2 – Players who tie divide the "winning" of the hole between them.
- 2-3 – Defines winning conditions for match play.
- 2-4 – Allows players to concede an opponent's stroke, a hole, and/or the round prior to or during play of that element of the game.
- 2-5 – Defines the procedures for resolving doubts and disputes.
- 2-6 – The general penalty for a rules infraction in match play is loss of the hole except when overridden by another rule.
- Rule 3 – Stroke play
- 3-1 – Defines stroke play in general as a variant in which players compete to play the entire round in the fewest strokes, and defines terms.
- 3-2 – No surrendering or concessions; a player who has not completed the current hole by holing out before moving on to the next one is disqualified.
- The ball is "holed" and the hole completed the ball has come to rest within the circumference of the hole and completely below the top lip of the hole. Slipouts, bounceouts, and other situations where the ball may fall in but not come to rest completely within the hole do not count as holing out.
- 3-3 – Defines procedure for doubt/dispute; allows a player in a doubted or disputed situation to play two balls and score the one that was played correctly.
- 3-4 – Refusal to comply with a rule affecting another player's rights during the game is a disqualification.
- 3-5 – The general penalty for a rules infraction in stroke play is two strokes except when overridden by another rule.
- Rule 4 – Clubs
- 4-1 – Clubs must conform to the specifications in Appendix II; generally, clubs must be of a "traditional form and make", and "plain in shape". Normal wear and tear does not make a club non-conforming if it was originally conforming as long as it is fit for play.
- 4-2 – The characteristics of a club cannot be changed during a round, and foreign material cannot be applied to the club to influence the ball.
- 4-3 – Clubs that become damaged and unusable by normal play may be repaired or replaced if it does not delay the game; clubs damaged in other means (frustration) cannot be used, repaired or replaced. A player may not borrow a club from another person playing to substitute a damaged one, nor assemble one from any spare parts that may be carried to repair clubs. If a club damaged in the normal course of play is unfit for play it may be replaced or repaired. Repair means to return the club to its original state.
- 4-4 – A player must not start a stipulated round with more than fourteen clubs. If two players are sharing clubs, the combined total clubs for both players must not exceed fourteen.
- The penalty for carrying, but not using, an illegal club (any non-conforming club or in excess of 14) is two strokes (or loss of hole) for each hole up to a maximum of two that was played while in violation. Any club carried in violation of Rules 4-3(iii) or 4-4 must be declared out of play to the marker or an opponent immediately upon discovery or the penalty is disqualification.
- The penalty for using a non-conforming club or more than 14 different clubs to make a stroke at the ball is disqualification.
- Rule 5 – Ball
- 5-1 – Balls must conform to the specifications of Appendix III, and may be required to be on a list of pre-approved balls.
- 5-2 – A ball must not have foreign material applied to it intentionally to influence its movement.
- 5-3 – A cut, split, cracked or deformed ball is unfit for play and must be replaced with another without penalty. Other players may dispute that a ball is unfit.
- Players may inspect their ball in play to determine if it is unfit without penalty, provided that they inform their fellow competitor(s) or the marker, mark the ball's position before lifting, do not clean the ball, and replace it if it is fit for play. An error in procedure or the lifting of a ball without good reason is a one-stroke penalty.
- A ball substituted for another under this rule when the original ball was fit for play may be lifted and replaced with the original ball without penalty (Rule 20-6), but if a stroke is made at the wrongly-substituted ball it's a two-stroke penalty.
- A ball that breaks in pieces during a stroke is replaced and played without penalty, and the stroke made at the broken ball is cancelled (does not count). "during a stroke" includes any point between the player's downswing and the moment the ball comes to rest, so a ball that breaks in pieces on impact with the ground or an obstruction after being hit falls under this Rule.
- Rule 6 – Player
- 6-1 – Players and caddies are responsible for knowing the rules, and players are responsible for the rules infractions of their caddies.
- 6-2 – Defines procedure for declaring and recording handicaps.
- 6-3 – Players must start their game at the appropriate time as instructed, and must stay with their arranged group for the entire round.
- 6-4 – Players may be assisted by one (and only one) caddy during the round.
- 6-5 – Players are responsible for playing the proper ball (the one belonging to them that is in play).
- 6-6 – One player is the "marker" and has the responsibility for properly marking the scores of each competitor in the group on their scorecard. The player himself is responsible for the scores recorded and must review the scores and raise any disputes before returning the scorecard.
- 6-7 – The player must maintain a pace as may be set by the course authorities and must not unduly delay play.
- 6-8 – The player must not discontinue play except for reasons stated, primarily when play is officially suspended, there is danger of lightning, or for other "good reason" (not including bad weather in and of itself). The rule further defines procedures for suspension and resumption of play.
- Rule 7 – Practice
- 7-1 – A player may practice on the course on the day of a match play competition, but must not practice on the course on the day or between rounds of a stroke play competition. Practice in designated areas is allowed.
- 7-2 – A player must not make any practice stroke during play of a hole or between holes. A practice swing does not count (the difference is generally that a "stroke" is a swing made with the intention of hitting a ball).
- Rule 8 – Advice
- 8-1 – A player must not give advice to a player other than his partner, and must not ask for advice from anyone other than his partner or caddy.
- 8-2 – A player may have the line of play (desired path of the ball) indicated to him by anyone when not on the putting green, but this line of play must not be indicated by any means other than the hole's flagstick while the stroke is made.
- 8-3 – A player, his partner or their caddy may point out a line for putting while on the green, but must not touch the green nor mark the path in any way.
- Rule 9 – Information as to strokes taken
- 9-1 – The number of strokes a player has taken at any given time always includes penalty strokes assessed.
- 9-2 – During match play, an opponent is entitled to know the number of strokes a player has taken during play of the current or just-completed hole, and must be given correct information.
- 9-3 – During stroke play, a player must inform the scorekeeper of any incurred penalty strokes as soon as is practical.
- Rule 10 – Order of play
- 10-1 – Defines the order of play during match play:
- The player who tees off first at the first tee is the first player listed on the scorecard if the scorecard was arranged by authorities; otherwise it is decided by lot or other equitable means. The player with the lowest score on the previous hole tees off first at the next hole.
- During play of a hole, the player whose ball is furthest from the hole plays next; if that can't be determined, any equitable system including by lot (coin flip) or mutual agreement may be used.
- A player who plays out of turn incurs no penalty, but the opponent who should have played next may require that the stroke be cancelled and replayed at the proper time.
- 10-2 – Defines the order of play during stroke play. Essentially the rules are the same as for match play (see previous), except that players may not demand a stroke made out of turn be cancelled, and instead course officials may disqualify players or groups that agree to play out of turn to give an advantage.
- 10-3 – A player playing a "provisional ball" (see Rule 27-2) from the teeing ground must do so after the other players of the group have teed off.
- Rule 11 – Teeing ground
- 11-1 – A player making their first stroke must do so from within the teeing ground, and may use an approved tee. The player may stand outside the teeing ground to play a ball within it.
- 11-2 – Tee markers (indicating the furthest-forward allowable line to place the ball when teeing off) are considered a fixed part of the course during a player's tee shot and may not be moved for any reason. After a player's tee shot, a tee marker is an obstruction and relief may be taken according to Rule 24.
- 11-3 – A ball that falls off the tee when a stroke is not being made at it may be re-teed without penalty. A ball that falls off the tee when a stroke is made at it counts as a stroke, and the ball must be played as it lies.
- 11-4 – Teeing off from outside the teeing ground is not a penalty in match play, but the opponent may require the stroke be cancelled and replayed from within the teeing ground. Teeing off from outside the teeing ground is a two-stroke penalty in stroke play and a ball must then be played from the teeing area. The stroke made from outside the teeing area and subsequent strokes made at that ball do not count.
- 11-5 – Teeing off from the wrong teeing ground (i.e. the "blue" tee when the "white" tee is supposed to be used) is equivalent in all respects to teeing off from outside the teeing ground as in 11-4.
- Rule 12 – Searching for and identifying ball
- 12-1 – A player is not necessarily entitled to see his ball when making a stroke at it. When searching for a ball, the player may generally move and bend long grass and similar, but in doing so must not improve his lie or remove obstructions to his swing or the path of the ball. There is a one-stroke penalty for moving the ball in general while searching for it, except that there is no penalty in any of the following (though the ball must be replaced):
- When searching for a ball believed to be buried in loose sand, the player may uncover the ball to identify it, but must then replace the sand that was removed to recreate the original lie.
- When searching for a ball in any hazard, loose impediments may be moved to identify the ball, but must then be replaced to recreate the lie as with sand.
- When searching for a ball in a water hazard (muddy/murky water) the player may search for it by probing with his club. A ball that is moved must be replaced (without penalty) unless the player chooses to relieve the ball from the hazard under rule 26-1.
- 12-2 – If a player cannot identify their ball but believes it to be theirs, they may, without penalty, lift and inspect it. The Rule provides requirements for the situation in which a ball is permitted to be lifted, and procedures to follow when permitted, and prescribes penalties for varying severity of infraction.
- Rule 13 – Ball played as it lies
- 13-1 – The ball must be played as it lies except as otherwise provided in the rules.
- 13-2 – A player must not alter the lie of his ball, the area of his stance or swing, his line of play, or the area in which he is to drop or place a ball. The rule gives specific actions that are, and that are not, infractions.
- 13-3 – A player is entitled to place his feet firmly on the ground when taking his stance, but must not "build" a stance (by moving the ground under his feet to attain a stable position).
- 13-4 – When a ball lies in a hazard, before making a stroke at it, the player must not test or touch the hazard in any way with his hand or club, nor move any loose impediment within the hazard. The rule provides for various exceptions.
- Rule 14 – Striking the ball
- 14-1 – Strokes must be made with a "fair" swing of the club at the ball, and not by pushing, scraping, cupping or other means.
- 14-2 – Players must make all strokes unassisted in any way by any other player, caddy or other person.
- 14-3 – Players must not use any "artificial equipment", "unusual equipment", nor may they use equipment in an unusual way to assist them in making a stroke, judging distance, or gripping the club. The rules provide for some exceptions and also allow the USGA to make rulings on equipment and uses of same at any time.
- 14-4 – If a player's club strikes the ball more than once while making a stroke, the stroke counts and a penalty stroke is added.
- 14-5 – A player must not make a stroke at a ball that is moving. Certain exceptions apply which are generally covered by other rules.
- 14-6 – A player making a stroke at a ball that is moving in water may do so without penalty but must not delay for the purpose of allowing the water to improve his lie.
- Rule 15 – Substituted or wrong ball
- 15-1 – A player must complete the hole with the same ball played from the teeing ground of the hole unless a substitute ball is introduced as provided in other rules.
- 15-2 – A player may introduce a substitute ball as permitted by other rules, or at any time with a two-stroke penalty.
- 15-3 – A player who hits a wrong ball (any ball other than that player's "ball in play") loses the hole in match play or incurs a two-stroke penalty in stroke play. The actual strokes made by a player at a wrong ball do not count. The rule provides for exceptions and for specific cases.
- Rule 16 – Putting green
- 16-1 – General rules:
- The putting line must not be touched by any player's hand or club, except that loose impediments may be removed, and in certain other circumstances.
- A player may lift his ball from the green to clean it, but must mark its position and must not lift it when another ball is in motion.
- Players may repair ball impact marks and damage from old holes whether or not they were made by the player and whether or not their ball is on the green. Moving a ball or ball marker during this process incurs no penalty if the ball or ball marker was moved for that express purpose and is replaced. No other damage may be repaired.
- A player must not test the green by any means including rolling a ball along it or roughing/scraping it. Exceptions are allowed for practice greens or the green of the previous hole unless course authorities have disallowed it.
- A player must not make a putt while standing astride the putting line or with either foot touching it, with exceptions made to avoid standing on another player's putting line.
- A player must not make a putt while another ball is in motion, but there is no penalty if the stroke was made in turn.
- 16-2 – Allows for a slight delay to see whether a ball that has apparently come to rest overlapping the hole falls in during the delay.
- Rule 17 – Flagstick
- 17-1 – Players may authorize another player or caddy to attend (stand within reach of), remove, and/or hold up the flagstick before making a stroke. Various notes define particular nuances; a significant one is that any player within reach of the flagstick is attending it, and if the player notices and does not object, they have authorized it by default.
- 17-2 – Attending, removing or holding up the flagstick must not be done during the stroke or while the ball is in motion if the player has not authorized it, and a player or caddy who does so incurs a penalty.
- 17-3 – Players incur a two-stroke penalty for hitting the flagstick or the attendant with the ball in certain circumstances:
- When the flagstick is attended, removed, or held up with authorization. If the attendant fails to remove the flagstick, or does not move from the line of putt thus causing the ball to strike them, even if the player had wished them to do so, the player still incurs the penalty. However, if an opponent or fellow-competitor attends the flagstick in the hole and fails to remove it for the purpose of making the player incur the penalty, the opponent incurs a two-stroke penalty under Rule 1-2 and may be disqualified for a serious breach of that rule.
- When the flagstick is unattended in the hole, and the player's last stroke was a putt from on the green. The flagstick must be removed from the hole when putting to remove a potential advantage to the player of having the flagstick stop the ball from rolling over the top of the hole.
- 17-4 – If the flagstick is in the hole and a player's ball comes to rest against it, and when the flagstick is removed the ball falls in, the player has holed out.
- Rule 18 – Ball at rest moved
- 18-1 – If a player's ball is moved while at rest by an outside agency (generally defined as anything other than a player, caddy, their equipment, and balls in play) there is no penalty; the ball must be replaced at its original lie.
- 18-2 – A player, partner or caddy who moves or causes his ball to move while at rest generally incurs a one-stroke penalty. There are certain situations where the penalty does not apply, including searching for a lost ball.
- 18-3 – An opponent or opponent's caddy in match play who causes a player's ball to be moved at rest incurs a penalty of one stroke, with certain exceptions (primarily while searching for the ball).
- 18-4 – A fellow competitor or caddy who causes a player's ball to be moved at rest must replace the ball; there is no penalty.
- 18-5 – A ball at rest that is struck by a moving ball must be replaced. There is no penalty. The owner of the moving ball must play it as it lies after it comes to rest.
- 18-6 – A ball moved during the course of measurement as required or allowed by another rule must be replaced without penalty.
- Rule 19 – Ball in motion stopped or deflected
- 19-1 – A player's ball which is stopped or deflected by any outside agency must be played as it lies without penalty, except in cases where the ball has come to rest in or on an outside agency, or was deliberately deflected or stopped by that outside agency.
- 19-2 – In stroke or match play, if a player's ball is accidentally deflected or stopped by himself, his partner or their caddies, the player incurs a one-stroke penalty. If it was deliberate, Rule 1-2 applies and a two-stroke penalty or loss of the hole is assessed.
- 19-3 – In match play, if a player's ball is accidentally deflected or stopped by his opponent or their caddy, there is no penalty and the player may choose to either cancel the stroke and play a ball from the original spot or as it lies (except in certain circumstances). If it was deliberate, Rule 1-2 applies and the opponent loses the hole.
- 19-4 – A ball deflected by a fellow competitor or their caddy in stroke play is governed by rule 1-2 (generally a two-stroke penalty for the competitor)
- 19-5 – A player's ball in motion which strikes another ball at rest must be played as it lies without penalty, unless both balls are on the putting green in which case the player incurs a two-stroke penalty. A player's ball in motion which is struck by another ball in motion must be played as it lies without penalty, except that if the stroke was made on the green, the stroke is cancelled and the ball placed at its previous lie.
- Rule 20 – Lifting, dropping and placing
- 20-1 – Prescribes general procedures for lifting and marking of a player's ball as prescribed by any Rule. In general the ball may only be lifted by the player, their caddy or another person the player has authorized, the ball must be marked if it is to be replaced, and it must be replaced in the marked spot.
- 20-2 – Prescribes general procedures for dropping and re-dropping a ball as prescribed by any Rule. In general a ball to be dropped must be dropped by the player who owns it, who must stand straight, hold the ball out and drop it from shoulder height and arm's length. Re-drops are made without penalty in certain situations.
- 20-3 – Prescribes general procedures for placing and re-placing a ball as prescribed by any Rule. In general a ball to be placed must be placed on the same spot from which that ball or the one it substitutes was lifted or moved.
- If the lie has changed, the player must place the ball in the nearest lie matching the original lie of the hole, within one clublength of the original spot and not nearer the hole.
- If the original spot cannot be determined, the ball must be dropped when "through the green" (between the tee box and putting green) or in a hazard, or placed when on the putting green, as close as can be determined to the original spot.
- If the ball does not come to rest on the spot where it was placed, it must be replaced without penalty. If it will not come to rest, it must be placed at the nearest point where it will come to rest, and either not in a hazard if not originally in one, or in the same hazard the ball was originally in.
- 20-4 – A dropped, placed or replaced ball becomes the ball in play once the drop or placement has been completed.
- 20-5 – Defines procedures for various parts of the course when a ball is to be played from the spot of the previous stroke. From the teeing ground the ball may be placed anywhere in that ground and may be teed. Through the green or in a hazard, the ball must be dropped and must strike the same part of the course as the original lie, and on the putting green the ball must be placed on the green.
- 20-6 – A ball that was incorrectly substituted, dropped or placed may be lifted without penalty, and the player must then proceed correctly.
- 20-7 – Prescribes procedures and penalties for playing a ball that was dropped or placed at the wrong spot. In general, the penalty in match play is loss of the hole while in stroke play it is a penalty of two strokes, and the player must play the ball from that spot. Additional procedures are prescribed if the player believes the incorrect placement gave them a significant advantage.
- Rule 21 – Cleaning ball
- A ball on the putting green may be cleaned whenever it has been lifted. A ball elsewhere on the course may be cleaned when lifted unless it was lifted under Rule 5-3, Rule 12-2, or Rule 22.
- A player who cleans his ball in violation of this Rule incurs a one-stroke penalty unless another Rule governing the lifting of the ball prescribes a penalty, in which case there is no additional penalty under Rule 21.
- Rule 22 – Ball assisting or interfering with play
- 22-1 – A ball that may assist another player in its current lie must be lifted by the player who owns it on the request of any other player, and may be lifted at the player's discretion. The ball must not be lifted if another ball is in motion. The ball lifted must not be cleaned unless it was on the putting green.
- 22-2 – A ball that may interfere with a player's own ball must be lifted by its owner on the request of that player, but must not be lifted in the absence of such a request unless the ball lies on the putting green in which case the player who owns it may lift it without a request to do so. The ball must not be lifted if another ball is in motion. The ball lifted must not be cleaned unless it was on the putting green.
- Rule 23 – Loose impediments
- A loose impediment is defined as a natural object that is not fixed or growing, not solidly embedded, and not adhering to the ball itself. Leaves, twigs, acorns, small stones, insects etc are loose impediments anywhere on the course. Sand and soil are loose impediments on the putting green but not elsewhere. Snow and ice may be considered loose impediments or "casual water" (an abnormal ground condition; see below) at the player's discretion. Dew and frost are not loose impediments.
- 23-1 – Except when the ball and a loose impediment are both in a hazard, or a ball is in motion that may be influenced by a loose impediment, the player may move or remove any loose impediment without penalty. Rule 18-2 applies if removal of the impediment cases a ball to move, except there is no penalty if the ball that was moved was on the putting green and was directly caused by removing the impediment.
- Rule 24 – Obstructions
- An obstruction is defined as any artificial thing, including roads, paths, signs, etc, except those things that define an out of bounds area, things that are out of bounds, and anything declared to be a part of the course.
- A movable obstruction is an obstruction that can be moved without unreasonable effort, undue delay or damage to the course. Otherwise it is immovable.
- 24-1 – A player may remove any movable obstruction from the line of play without penalty. Relief must not be taken when a ball is in motion that may be influenced by the obstruction.
- If the ball does not lie in or on the obstruction, it is played as it lies, and a ball that is moved as a result of removing the obstruction must be replaced without penalty.
- If the ball lies in or on an obstruction, the ball may be lifted, the obstruction removed, and the ball must be dropped (or placed if on the putting green) as near to the ball's original spot as possible but not nearer to the hole.
- The ball may be cleaned if lifted under this rule.
- 24-2 – A player may take relief from an immovable obstruction when the ball lies in or on the obstruction, or the obstruction interferes with a player's stance, swing, or line of putt (but not their line of play when not on the putting green).
- Through the green, the player must lift their ball and then drop it within one clublength of the "nearest point of relief" (the closest point to the obstruction not nearer to the hole that allows for a proper stance and swing) that is not a hazard or the putting green, without penalty.
- If in a hazard, the ball must be lifted, and may be dropped in the nearest point of relief within the hazard without penalty, or may under penalty of one stroke be dropped at any point behind the bunker and in line with the pin and the original lie.
- On the putting green, the ball must be placed at the nearest point of relief, which may not be in a hazard but may be outside the green.
- The ball may be cleaned when lifted under this rule.
- Relief may not be taken if it is not the obstruction alone that makes a stroke impracticable, or if the interference occurs due to use of an unreasonable, abnormal stance or swing, or if the ball lies in a water hazard.
- 24-3 – A player may substitute another ball without penalty if the ball lies in or on an obstruction and is not found. The ball is deemed to lie at the spot of a movable obstruction or the spot at which the ball crossed into an immovable obstruction, and relief is generally taken as per 24-1 or 24-2 as if the ball had been lifted from that spot. Relief is not available under this rule from an obstruction in a water hazard.
- Rule 25 – Abnormal ground conditions, wrong green
- An abnormal ground condition is defined as any "casual water" (puddles or standing water that is not a water hazard, dew or frost), "ground under repair" (simply ground marked as such by the groundskeeping staff) or damage to the course made by a burrowing animal, reptile or bird. Aeration holes may be considered abnormal ground by local rule, with the "nearest point of relief" usually defined as the closest spot that isn't an aeration hole (not the nearest spot outside an area that has been aerated).
- 25-1 A player may take relief from an abnormal ground condition in a similar manner as for Rule 24-2; the ball must be lifted and then dropped within one clublength of the nearest point of relief from the ground condition.
- As with obstructions, relief is not available from an abnormal ground condition under this rule when the ball has come to rest in a water hazard.
- If the ball is not found but is known to be in the abnormal ground condition, the player may drop or place a substitute ball as if it were lifted from the abnormal ground condition, except when the abnormal ground condition is in or borders a water hazard.
- 25-2 – A ball that is embedded in its own impact mark in the fairway or rough may be lifted, cleaned and dropped without penalty, as close to the original spot as possible but not nearer the hole.
- 25-3 – A ball that is on a putting green other than the one for the hole on which the player is playing must not be played as it lies. Instead, the player must, without penalty, lift the ball, and drop it within one club-length of the nearest point of relief that is not a hazard or putting green. The ball may be cleaned when lifted.
- Rule 26 – Water hazards
- 26-1 – When a ball is known to have come to rest in a water hazard, the player has two options for relief from the hazard, both under penalty of one stroke.
- They may play a ball from a spot as near as possible to the spot from which the last stroke was made. Similar to Rule 27-1.
- They may drop a ball at a spot behind the water hazard and in line with the hole and the spot where the ball is believed to have crossed the water hazard. Similar to Rule 28(b).
- In the special case of a lateral water hazard (bordering the course and roughly parallel to the direction of play), the player may drop a ball within two clublengths and not nearer to the hole from the spot where the ball crossed the water hazard, instead of behind and in line with the hazard. Similar to Rule 28(c).
- The ball played may be the original ball, recovered from the hazard, or a substitute ball with no additional penalty.
- 26-2 – Prescribes relief for a player who has elected to play a ball within a water hazard and then seeks relief. Situations include hitting into the same hazard, or hitting outside the hazard into an unplayable lie or out of bounds. Penalties are one or two strokes, depending on the exact situation and form of relief.
- Rule 27 – Ball lost or out of bounds; provisional ball
- 27-1 – Describes the "stroke and distance" penalty (a ball may be played from the spot of the last stroke under penalty of one stroke), and prescribes its use when a ball is hit out of bounds or is lost and not found within 5 minutes.
- 27-2 – Describes the "provisional ball"; in a case where a ball may be lost, out of bounds, or unplayable, a player may play a provisional ball from the same spot as his last stroke. If the original ball is found and the player wishes to use it, it is played as it lies without penalty. If the provisional ball is used to complete the hole, the player adds one penalty stroke (making the play of the provisional ball a stroke-and-distance penalty).
- Rule 28 – Ball unplayable
- A player may, at any time except when the ball is in a water hazard, declare his ball unplayable and seek relief. Under a penalty of one stroke, the player may:
- Play the ball or a substitute ball from the same spot as the previous stroke as per Rule 27-1.
- Lift and drop the ball or a substitute ball behind the spot of the previous lie and in line with the hole. If the ball is in a bunker, the ball must remain in the hazard.
- Lift and drop the ball or a substitute ball within two clublengths of the previous lie and no nearer to the hole. If the ball is in a bunker, it must remain in the bunker.
Further rules (29–34) describe alternate forms of play and the administration of courses and competitions by a local "committee".
Appendix I contains information regarding "Local Rules". Local Rules supplement or override the normal rules of play and are used to define proper procedure in special situations that might exist on a specific golf course or during a specific time of year, such as defining specific areas of ground under repair or abnormal ground conditions, or defining certain things as "movable/immovable obstructions" or "loose impediments" that normally would not be. These rules are usually available from the course or tournament authorities and usually take precedence over any standard rule of play whenever there is a conflict. Part B of the Appendix lists several example Local Rules that courses may use for all play. Part C lists several example Local Rules that may be in effect during competitions.
Appendices II, III and IV generally describe the required configuration of clubs, balls, and other devices respectively. Players who buy clubs, balls and other golfing equipment at retail stores and do not modify them before use will generally be in compliance with these rules; however, companies can and do make non-conforming equipment such as novelty golf balls and "long-drive" clubs; players should examine the packaging of any equipment to determine that it is, or is not, suitable for sanctioned play by strict rules.
In addition to the Rules and Etiquette, a number of interpretations of the Rules have been published by the USGA/R&A that prescribe the proper procedure in certain situations where the Rules themselves may not be clear. The Decisions are numbered based on the Rule or sub-rule being interpreted and the order in which Decisions were published.
Decisions may be simple clarifications. For instance, a note in Rule 17-1 says anyone "standing near" the flagstick is deemed to be attending it. This is vague, so Decision 17-1/1 states that anyone close enough to touch the flagstick is "standing near" it. Decisions may also define the proper procedure in exceptional or unforeseen cases. For instance, Decision 6-6a/4 states when the scorekeeper refuses to sign a card after a dispute about his fellow-competitor's score is decided by the committee in favor of the fellow-competitor, there is no penalty; the scorekeeper should not attest to any score he believes incorrect even if he is overruled, but the score may be attested by another witness, or may be accepted by the committee without being attested. Decisions may also rule that specific actions, equipment or fixtures used by a player or implemented by the committee or course are legal or illegal; for instance, most decisions regarding Rule 14-1 define specific actions that are and are not "fair" swings at the ball, and general Decisions on rule 17 define alterations to a flag or attachments to the flagstick that may be made by the course authorities to indicate the relative position of the hole on the green, or aid in distance determination.
These decisions are binding in situations where they apply, as they define the proper implementation of the Rules themselves. They are not included in most rulebooks, but like the Rules they are available for reference on the USGA website.
Notable rule changes 
The biggest change that came with the 2008–2011 edition was a new rule about clubheads not having too much 'spring' effect. This has led to the publishing of lists of conforming and non-conforming drivers.
In 2010 a new rule governing grooves came into force for professional and high level amateur competition. The change was made in order to decrease the amount of back spin that players were able to produce, particularly from the rough. However, due to a previous legal settlement with Ping following an earlier rule change in the early 1990s, their Eye 2 irons, which were otherwise non-conforming, were deemed legal. This led to a controversy in the early stages of the 2010 PGA Tour season when Phil Mickelson used these irons. While Mickelson's use of the irons was ruled legal, Ping decided to surrender its remaining rights under the now-20-year-old legal settlement, and the original Ping Eye 2 sets are now officially non-conforming. Ping continues to produce a set of wedges with this name and general shape, but these new Ping Eye 2 wedges have conforming face and groove designs.
The 2012–2015 edition was published October 24, 2011. Nine rules were changed, the most significant being Ball Moving After Address (Rule 18-2b). Rory McIlroy was penalized by this Rule in the final round of the 2011 Open Championship.
A proposed change for the 2016 edition will add Rule 14-1b, which will forbid players from anchoring a club against their body in any way (such as directly against the body or by using their forearm). While the rule change is expected to prominently affect the users of long putters, the two governing bodies stated that "the proposed rule narrowly targets only a few types of strokes, while preserving a golfer's ability to play a wide variety of strokes in his or her individual style."
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- "A guide to the rules of golf". BBC Sport. 2008-07-17. Retrieved 2010-09-08.
- "First rules of golf". National Library of Scotland. Retrieved 2010-09-08.
- Hutchinson, John. "Historical Rules of Golf". ruleshistory.com. Retrieved 2010-09-08.
- Rules FAQs
- USGA, R&A announce new Rules Of Golf for 2012 October 24, 2012.
- Rules of Golf USGA 2012
- List of conforming drivers
- List of non-conforming drivers
- Dixon, Peter (February 1, 2010). "Phil Mickelson at centre of ‘cheat’ storm". The Times (London). Retrieved 2010-09-07.
- USGA and R&A announce changes to Rules of Golf for 2012-2015, PGA, 24 October 2011, retrieved 28 October 2011
- "Long putters could be banned under proposed rule changes to golf". The Independent. Retrieved 28 November 2012.
- Buteau, Michael (2012-11-28). "Ban on Anchored Strokes Proposed by Golf Rulemakers in 2016". Bloomberg News. Retrieved 2012-11-28.
- Rules of Golf R&A 2008–2011
- USGA Rules of Golf video
- Browse the 2012 Rules of Golf
- Royal and Ancient Golf Club website
- United States Golf Association website