[LAWS]2017 Laws
11.4 OFFSIDE UNDER THE 10-METRE LAW
(a) When a team-mate of an offside player has kicked ahead, the offside player is considered to be taking part in the game if the player is in front of an imaginary line across the field which is 10 metres from the opponent waiting to play the ball, or from where the ball lands or may land. The offside player must immediately move behind the imaginary 10-metre line or the kicker if this is closer than 10 metres. While moving away, the player must not obstruct an opponent or interfere with play.
Sanction: Penalty kick
(b) While moving away, the offside player cannot be put onside by any action of the opposing team. However, before the player has moved the full 10 metres, the player can be put onside by any onside team-mate who runs in front of the player.
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[LAWS]2018 Laws
10.4. An offside player may be penalised, if that player:
c. Was in front of a team-mate who kicked the ball and fails to retire immediately to an imaginary line across the field 10 metres on that player’s side from where the ball is caught or lands, even if it hits a goal post or crossbar first. If this involves more than one player, then the player closest to where the ball lands or is caught is the one penalised. This is known as the 10-metre law and still applies if the ball touches or is played by an opponent but not when the kick is charged down.
6. Other than under Law 10.4c, an offside player can be put onside when:
a. That player:
i. Moves behind a team-mate who last played the ball; or
ii. Moves behind a team-mate who is onside.
b. An onside team-mate of that player moves past the offside player and is within or has re-entered the playing area.
7. A player offside under Law 10.4c cannot be put onside by any action of an opponent, apart from a charge down.
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I understand CTPE's problem. Where the 2017 laws stated it clearly, the 2018 doesn't. So much for shorter but not simpler.