16.7 UNSUCCESSFUL END TO A RUCK
(a) A ruck ends unsuccessfully when the ball becomes unplayable and a scrum is ordered.
The team that was moving forward immediately before the ball became unplayable in the ruck throws in the ball.
If neither team was moving forward, or if the referee cannot decide which team was moving forward before the ball became unplayable in the ruck, the team that was moving forward before the ruck began throws in the ball.
If neither team was moving forward, then the attacking team throws in the ball.
(b) Before the referee blows the whistle for a scrum, the referee allows a reasonable amount of time for the ball to emerge, especially if either team is moving forward. If the ruck stops moving, or if the referee decides that the ball will probably not emerge within a reasonable time, the referee must order a scrum.