Teams advance the ball by running or kicking it. Players may pass the ball to and from each other, but not forward. Defensive players try to tackle the ball carrier, as in football. Players score by running the ball past the opposing "try line" or kicking it through the goal posts. There are two similar forms of the sport, Union Rugby and League Rugby, with some different scoring values and rules.
Methods of Scoring
The most valuable way of scoring, a "try," is achieved by advancing the ball past the try line -- rugby's version of the goal line in American football. Rugby features H-shaped goal posts and three ways of scoring through those posts: conversion kicks after a successful try, place kicks after a penalty and a drop kick during play.
Union Rugby Rules
Union play features teams of 15 on the field, eight forwards and seven backs, plus substitutes. After tackles, teams contest the ball with a "ruck" or a "maul." A try is worth 5 points. After a try, a successful conversion kick scores 2 points. A kick for goal after a penalty is worth 3 points, as is a successful drop kick.
Rucks and Mauls
After being tackled to the ground, a player must release the ball. Under Union rules, a "ruck" forms. A group of players from both teams gathers over the loose ball, trying to move it to their side with their feet while pushing against their rivals. When a player is tackled upright under Union rules, a "maul" forms. Forwards from each side lock onto the ball carrier and try to wrestle the ball back to their side with their hands and arms.
League Rugby Rules
This form of rugby features teams of 13 -- six forwards and seven backs -- plus substitutes. After tackles, teams do not contest the ball as they do in Union. Instead, they "play the ball." League scoring varies from Union scoring. A try is worth 4 points, with a following conversion kick scoring 2 points. A successful place kick after a penalty is worth 2 points, while a successful drop kick during play tallies 1 point. If a team fails to score before it suffers six tackles, it must surrender the ball. Usually a team does that by kicking the ball on the sixth possession to move the other team back. Union rules feature no such six-tackle restriction.
Play the Ball
After a tackle under League rules, there is no ruck or maul. The tackled player gets up, places the ball in front of his foot, then uses his foot to roll the ball back to the next receiver on his team. The defending team must back up 10 meters. The two defenders guarding the "play the ball" area stand one behind the other. They can advance as the ball is rolled back by the tackled player. Play continues.
When a ball carrier loses the ball onto the field, the defense is awarded the ball and a scrum forms among the forwards -- eight players under Union rules and six under League rules. Forwards from the teams bind together. The team in possession puts the ball on the ground between the sides. The two sides push against each other, fighting to gain possession. The objective is to kick the ball back behind your side and restart play.