If you think a ball is yours but cannot see your identification mark, after notifying your marker or opponent, you may mark the position of the ball and lift it to identify it. When lifted under this Rule, the ball may not be cleaned except to the extent necessary to identify it (Rule 12-2).
Play the ball as it lies. Don’t improve your lie, the area of your intended stance or swing, or your line of play by:
- moving, bending or breaking anything fixed or growing, except in fairly taking your stance or making your swing, or
- pressing anything down (Rule 13-2).
If your ball is in a bunker or a water hazard, don’t;
- touch the ground (or the water in a hazard) with your hand or club before your downswing, or
- move loose impediments (Rule 13-4).
If you play a wrong ball (i.e. stray ball or ball being used by another player):
- in match play you lose the hole
- in stroke play you incur a two-stroke penalty, the strokes made with the wrong ball do not count and you must correct the mistake by playing the correct ball (Rule 15-3).