3.3 WHEN THERE ARE FEWER THAN FIFTEEN PLAYERS

A Union may authorise matches to be played with fewer than fifteen players in each team. When that happens, all the Laws of the Game apply except that each team must have at least five players in the scrum at all times.
Exception: matches between teams of Seven-a-side are an exception. These matches are covered by the Seven-a-side Variations to the Laws of the Game.