While the proper term is foursomes, most US golfers refer to this format as alternate shot. As defined in Rule 29 of the Official Rules of Golf, Foursomes are played between two teams of two golfers, each of which plays just one ball. Players on each team alternate teeing off, and then alternate each shot thereafter.
Example: Player A tees off while his partner, B, watches. Player B then hits the ball from where it lands after A’s shot. Then it’s A’s turn until the ball is in the hole. On the next hole, Player B tees off, even if he took the final putt.
Foursomes can be scored as either match or stroke play.
A couple of special rules apply:
In Foursomes match play, if a ball is played out of order—that is, if A takes a stroke when it’s B’s turn—the hole is lost.
In Foursomes stroke play, a ball played out of order results in a two stoke penalty. The offending team must correct the error before playing from the next tee. That is, if A accidentally took a stroke on B’s turn, A must hit again, with a two stroke penalty to get back into the proper order.
If the error is not corrected before the next tee shot, the offending team is disqualified.
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