8.1 The Referee must carry a whistle which he shall blow whistle to commence and terminate each half of the game.
Except for these occasions the blowing of the whistle shall temporarily stop the play.
The Referee shall blow the whistle:
(a) when a try or a goal has been scored
(b) when the ball has gone out of play
(c) when restarting play, other than at a scrum
(d) when he detects a breach of the Laws of the Game, except when to stop the play would be to the disadvantage of the non-offending team
(e) when play is irregularly affected by the ball or the player carrying the ball coming into contact with the Referee, a Touch Judge, or with any person not taking part in the match or with any object which should not normally be on the playing field
(f) when any irregularity, not provided for in these Laws, occurs and one team unjustifiably gains an advantage
(g) when a stoppage is necessary in order to enforce the Laws or for any other reason.