• a. During Search
If, during search for a player’s ball, an opponent, his caddie or his equipment moves the ball, touches it or causes it to move, there is no penalty. If the ball is moved, it must be replaced.
• b. Other Than During Search
If, other than during search for a player’s ball, an opponent, his caddie or his equipment moves the ball, touches it purposely or causes it to move, except as otherwise provided in the Rules, the opponent incurs a penalty of one stroke. If the ball is moved, it must be replaced.
(Playing a wrong ball – see Rule 15-3)
(Ball moved in measuring – see Rule 18-6)
18-4. By Fellow-Competitor, Caddie or Equipment in Stroke Play
If a fellow-competitor, his caddie or his equipment moves the player’s ball, touches it or causes it to move, there is no penalty. If the ball is moved, it must be replaced.
(Playing a wrong ball – see Rule 15-3)
18-5. By Another Ball
If a ball in play and at rest is moved by another ball in motion after a stroke, the moved ball must be replaced.
18-6. Ball Moved in Measuring
If a ball or ball-marker is moved in measuring while proceeding under or
in determining the application of a Rule, the ball or ball-marker must be
replaced. There is no penalty, provided the movement of the ball or
ball-marker is directly attributable to the specific act of measuring.
Otherwise, the provisions of Rule 18-2a, 18-3b or 18-4 apply.
*PENALTY FOR BREACH OF RULE:
Match play – Loss of hole; Stroke play – Two strokes.
*If a player who is required to replace a ball fails to do so, or if he makes a stroke at a ball substituted under Rule 18 when such substitution is not permitted, he incurs the general penalty for breach of Rule 18, but there is no additional penalty under this Rule.
Note 1: If a ball to be replaced under this Rule is not immediately recoverable, another ball may be substituted.
Note 2: If the original lie of a ball to be placed or replaced has been altered, see Rule 20-3b.
Note 3: If it is impossible to determine the spot on which a ball is to be placed or replaced, see Rule 20-3c.
©USGA, used with permission
