Offside is a very difficult rule in Rugby union as it is changing constantly in play and both sets of players (Team in possession and the team defending) can be offside.
To make it easier, i will use examples (during which Team 1 will always be in possession and Team 2 will be defending). Also, during all of this, the player is only offside if the player is active (ie. interfering in any way with any player or the ball)
1st, a player from team1 is offside is he is in front of the ball. The only exception to this rule is if the team1 kicks the ball and that player retreats. If he procedes to chase the ball he is offside. As soon as the kicker is in front of him, he is back onside. A player from team2 cannot be offside if the ball is in open play.
2nd, If a ruck or maul forms or it is a scrum, a player from team2 is offside is he is further forward that than the ruck, maul or scrum. A player from team 1 is offside is he is further forward that the ball (but only if he is not part of the ruck, maul or scrum).
3rd In the case of a throw-in, an imaginary line goes across the pitch from where the throw is taken from. All players in the line out must be 1m away from that line, on there own side and cannot cross that line until one team has the ball secured (a lineout usually has 7 players per team and that includes the scrum half who stands just beside the line out to receive the ball if whoever catches the ball decides to pass the ball out of the lineout). Any player who is not part of the lineout must be 10 metres away and cannot interfere with play until the ball has been secured and has passed out of the lineout.
Finally, an execption to a player on team1 if the ball is kicked from a restart. If the player is in front of the kicker but still inside the deadball area, when the ball is kicked, then he is still onside.
football/soccer and rugby are the only ones i can think of
In rugby union-30, 15 a side
Belgium's national rugby union side and nicknamed the "black devils"
rugby
Kick off.
Rugby League has 13 players on each team. Rugby Union has 15 players on each team. There is a recognised game of seven-a-side in Rugby Union.
In Rugby Union: 30 + 1 referee + 2 assistant referees = 33. In Rugby League 26 + 1 referee + 2 touch judges/linesmans = 29.
Throughout the game either one side or the other has possession of the ball. At the end of the game the referee calls "no side" to indicate that neither side has possession of the ball thereafter.
Rugby is a fun sport to play. It also helps you get fit and helps your brain to think well on how to get past your opponents to the other side and score a try! If you have not played rugby, go out with your friends and try it. You will see the fun in side you!
The ruck forms when the carrying player is grounded and the two teams attempt to push each other off to gain access to the ball - There is no specific side as the ball can be stolen
There are 13 players on the pitch in each rugby league side, as opposed to 15 in rugby union teams. The difference is in the forwards. Rugby union teams have 8, but rugby league teams survive with only 6.
There are two crusader teams. One are the rugby league side Celtic crusaders and one is the union side from Canterbury in the South Island of New Zealand.