Stuck on scrums? Confusing your fly-halfs and flankers? Check out Newsround's special guide to all things rugby with a bit of help from England World Cup winner Lawrence Dallaglio!
The aim of the game is to score as many trys as possible. Players can score a try by putting the ball on the ground with two hands over the oppositions line. A try is worth 5 points.
A conversion can be scored after a try and is worth 2 points. To score a conversion a player must kick the ball between the two goal posts. If successful then a coverted try is scored which is worth 7 points.
Another way of scoring is through a goal-kick. If a player kicks the ball between the goal posts either during the match (called a drop goal) or from a penalty he is awarded 3 points.
A scrum is when 8 forwards from one team collide with 8 forwards from the opposing team. A scrum happens when the ball goes out of play and it's a way of re-starting the match.
Some people think that the fly-half is the most important player on the pitch. He is normally the best kicker and should control his team's play - where they're running and where the ball goes.
Flankers play on the sides of the pitch and usually work in twos. They are important in the scrum and are expected to be the first people to get hold of the ball when it goes out of play.
When a tackled player hits the ground he must let go of the ball. Both teams can then try to get possession of the ball. If no player gets the ball in 5 seconds then the ref can call for a scrum.
The sin-bin is the place all players want to avoid! All players who have committed a yellow card offence have to leave the game for 10 minutes and sit on a bench called the sin-bin. Unlike football, anyone the ref shows a yellow card must leave the pitch straight away, but can come back after their 10-minute "rest"!