The Offside Rule, Explained Simply

Offside is the rule that stops attackers from waiting near the opponent's goal for a long ball. It is judged at the moment the ball is played by a teammate, not when the attacker receives it. Three things have to be true at that moment for a player to be offside: they are in the opponents' half, they are nearer to the opponents' goal line than both the ball and the second-last opponent, and they are involved in active play by interfering with play, interfering with an opponent, or gaining an advantage from being in that position. Being level with the second-last opponent is not offside. The second-last opponent is usually the last defender once the goalkeeper is counted, which is why the phrase 'last defender' is slightly misleading. There is no offside from a throw-in, a goal kick or a corner kick. A player who receives the ball in their own half is never offside, however far forward they were standing when the ball was played. Because it is judged at the instant of the pass, using a line that has to be drawn across a moving picture. Two reasonable people can disagree about when the ball left the passer's foot. That is a refereeing problem, not a rule problem, and it is why the explanation above is phrased as conditions rather than as a distance. Nothing directly - but it is the reason supporters argue about numbers. Assistant referees read numbers to report offences, so a squad whose numbers are small, low-contrast or placed on a busy pattern creates avoidable confusion. Number size and contrast are confirmed with the artwork rather than left to the mockup. Indirectly, through the back line. Defenders who hold a high line spend the game turning and running, which is why defensive shirts are usually specified with the same fabric as the rest of the outfield kit rather than a heavier option. The kit is one specification per squad unless the club asks for a separate goalkeeper set.