Ahead of the kick.

Stefan Terblanche of the Sharks kicks high downfield and chases. As Terblanche was chasing and before he had passed him Johann Muller, the Shark lock with 5 on his back, moves forward.

The referee gets the number wrong but the decision right. Muller did advance. In fact he had moved to within 10 metres of where the ball came down.

Law 11.1 OFFSIDE IN GENERAL PLAY
(a) A player who is in an offside position is liable to sanction only if the player does one of three things:
• Interferes with play or,
• Moves forward, towards the ball or
• Fails to comply with the 10-Metre Law (Law 11.4).
A player who is in an offside position is not automatically penalised.
A player who receives an unintentional throw forward is not offside.
A player can be offside in the in-goal.
(b) Offside and interfering with play. A player who is offside must not take part in the game.
This means the player must not play the ball or obstruct an opponent.
(c) Offside and moving forward. When a team-mate of an offside player has kicked ahead, the offside player must not move towards opponents who are waiting to play the ball, or move towards the place where the ball lands, until the player has been put onside.

Muller was in an offside position, he moved towards opponents and he failed to comply with the 10-metre law.