A right-handed player's ball is so close to a boundary fence on the left of a hole that the player, in order to play towards the hole, must play left-handed.
In playing a left-handed stroke, the player's backswing would be interfered with by an immovable obstruction.
Is the player entitled to relief from the obstruction?
The player is entitled to relief since employment of an abnormal (left-handed) stroke is necessary in the circumstances — see Exception under Rule 24-2b.
The proper procedure is for the player to take relief for a left-handed stroke in accordance with Rule 24-2b(i).
The player may then use a normal right-handed swing for his next stroke. If the obstruction interferes with the swing or stance for the right-handed stroke, the player may take relief for the right-handed stroke in accordance with Rule 24-2b(i).
This rule appeared on USGA's website.