Over the years we have many times seen goals disallowed as the players have been called offside. But the rule in itself has often been difficult to explain.
Reuters
So what is the offside rule exactly? When is a player offside? Well, it happens if any part of their body except the hands and arms is in the opponents’ half of the pitch and closer to the opponents’ goal line than both the ball and the second-last opponent.
Yes, it sounds complicated but really is not. The assistant referees have to keep an eye on what is going on. The rule originated as early as the game itself and is on record as to have been used well over 150 years ago.
It is not a foul though, no player is sent off or penalised for being offside. But a goal scored in an offside position is not counted and it has resulted in turning many matches.
In 1990 the law was amended to adjudge an attacker as onside if level with the second-to-last opponent.