The laws of Rugby Union are defined by World Rugby (originally the International Rugby Football Board, and later International Rugby Board) and dictate how the game should be played. They are enforced by a referee, generally with the help of two assistant referees.

When playing a game of Rugby Union the overall objective is to score more points than the opposition through tries and goals. A try worth five points is scored when a team grounds the ball in the opposition's in-goal. A conversion (kick at a goal) is then attempted by either place- or drop-kicking the ball between the H-shaped goal posts and above the crossbar. If successful this is worth two extra points.

Penalties are awarded for major infringements such as offside or foul play and the team that is awarded them can choose to take a shot at goal in an attempt to score three points. They can also use the penalty to kick for territory or tap the ball and continue running it. Three points are awarded if a team member drop kicks a goal during general play.

The game of Rugby evolved at Rugby School from early folk football, with the rules of play being agreed upon before the start of each match. Some Rugby clubs were also early members of The Football Association, leaving after they left out rules for "running with the ball" and "hacking" when framing their code in 1863. The rugby laws were standardised in 1870 and the International Rugby Football Board (now World Rugby) was formed in 1886. In 1930 the IRFB was made responsible for developing any new laws. These laws have changed over time. The point value for scoring tries has increased from zero to five, penalties were initially worth just two points and drop goals four. The ball has changed too, going from a pig's bladder to a rubber bladder in first a leather and nowadays, a plastic case, and becoming more oval in shape. Player numbers were initially 20 each side, but reduced to 15 in 1877. The laws are always being tweaked in the early twenty-first century, with some of the biggest changes being introduced in 2009.

The game is usually played on a grass field approximately by . At each end of the field are the goal posts and an in-goal area. Games last for eighty minutes and are divided into two forty-minute halves. Each team defends one end and attempts to score points through tries and goals. One team kicks the ball towards the opposition starting play. At half time they swap ends, with the other team kicking off. After a successful kick-off the ball is in general play and can be passed, kicked, caught, picked up or grounded by any player. The ball can be kicked in any direction, but may only be passed backwards. Players attempt to stop the opposition running the ball by tackling them. Rucks form when at least one player from each team is on their feet and the ball is on the ground. Mauls are formed when the ball carrier is held by at least one of the opposition and a teammate is also bound to them. Players can compete for the ball at tackles, rucks and mauls in accordance with the laws.

Scrums are used to start play after minor infringements (knock-ons and forward passes) and when the ball becomes unplayable. All eight members of the forwards must be involved in the scrum provided the team still has all fifteen players present. Players involved in the scrum stay bound to each other and the opposition until it is finished and the rest, except the scrum-half, must be positioned at least five metres back. The two teams push against each other and the hookers strike for the ball once the scrum half puts the ball into the "tunnel" (gap between the two front rows). The scrum half must put the ball straight down the centre of the tunnel, if the scrum half deliberately puts the ball in at an angle to his second rows feet, (feeding the ball), the opposition are awarded the 'put in'.

Lineouts are used to restart play when the ball has crossed the sidelines. Players form two parallel lines perpendicular to the sideline and the team that did not put the ball out throws it straight down the middle. Players in the line-out can be lifted by teammates as they attempt to win the ball.

History

The early rules of football were determined by pupils before the game, with the legality of carrying or running with the ball often agreed shortly before commencement. The first set of written rules were published by pupils at Rugby School in 1845 and while a number of other clubs based their games on these rules there were still many variations played. The Football Association intended to frame a universal code of laws in 1863, but several newspapers published the 1848 Cambridge rules before they were finalised. The Cambridge rules included rules for "running with the ball" and "hacking" (kicking an opponent in the shins) which were not part of the Football Association draft. They decided not to include those rules in their release, causing a number of rugby clubs to break away from the Football Association.

The rules for playing rugby still differed between clubs, so in 1870 twenty one clubs formed the England-based Rugby Football Union (RFU) and standardised the laws of the game. As the game spread internationally disagreements arose over interpretations of the laws. Scotland, Ireland and Wales formed the International Rugby Football Board (IRFB) in 1886, with the RFU joining in 1890. The IRFB oversaw games between the four nations and in 1930 was made responsible for developing any new laws.

The balance in value between tries and conversions has changed greatly over the years. Historically, no points at all were awarded for a try, the reward being to "try" to score a goal (to kick the ball over the cross bar and between the posts). Scoring points from tries was not introduced until the late 1880s. Until 1891, a try scored one point and a conversion two. For the next two years tries scored two points and conversions three, until in 1893 when three points were awarded for a try and two for a kick. The number of points from a try increased to four in 1971 and five in 1992.Scoring through the ages rugbyfootballhistory.com In 1891 penalties were increased from two to three points, while drop goals were awarded four points (drop goals were subsequently reduced to three points in 1948). Before 1905 it was possible to score by kicking the ball through the posts from the ground in open play and in 1977 it was also possible to score three points by kicking a goal after taking a mark before both methods were banned in their respective years.

The defence was originally allowed to attempt to charge down a conversion kick from the moment the ball was placed on the ground, generally making it impossible for the kicker to place the ball himself and make any kind of a run-up. In 1958, the law governing conversions changed to allow the kicker to place the ball, prohibiting the defence from advancing toward the kicker until he begins his run-up.

The ball used until the 1860s was leather around a pigs bladder and was almost spherical. In 1862 rubber bladders were introduced and balls began to be manufactured with a more pronounced oval shape. In 1892 the RFU developed compulsory dimensions for the ball in the Laws of the Game for the first time. In the 1980s leather-encased balls were replaced with balls encased in synthetic waterproof materials. In 1877 the number of players was reduced from 20 to 15 a side.

The IRB trialled 23 changes to the modern laws in 2006 and some competitions in Scotland and Australia adopted them in 2007. In 2008, 13 of the variations were trialled globally. Important changes included: no gain in ground if the ball is kicked directly into touch after it has been moved back into the 22 by the kicking team; the offside lines for backs moved five metres from the scrum; allowing mauls to be legally pulled down and players to enter with their head lower than their hips; no restrictions on the number of players in a line-out; and allowing pregripping and lifting. In 2009 the IRB approved 10 of the laws, rejecting the laws relating to mauls and numbers in a line-out.

More recently, New Zealand Rugby, in co-operation with World Rugby, is set to trial several significant changes in the 2016 Mitre 10 Cup: Games will be officiated by two referees, as in the National Rugby League of Australian rugby league. The term "ruck" will be removed from the rules and replaced by "breakdown". A breakdown will form once one attacking player is over the ball on the ground. This in turn means that defenders can only make a play for the ball with their hands after a tackle if they arrive before any other attacking player. Tacklers' rights to the ball will be restricted to 180 degrees, instead of 360 as in the current laws. This makes it nearly impossible for a defender to steal the ball while making a tackle. Once a breakdown forms, players cannot play the ball with the hands, but can enter the breakdown from any angle as long as they were in an onside position. At the breakdown, the offside line will be one metre behind the hindmost foot.

Objective

Rugby union is a contact sport that consists of two teams of fifteen players. The objective is to obtain more points than the opposition through scoring tries or kicking goals over 80 minutes of playing time, divided into two 40-minute halves.

Play is started with one team drop kicking the ball from the halfway line towards the opposition. The rugby ball can be moved up the field by either carrying it or kicking it. However, when passing the ball it can not be thrown forward. The opposition can stop players moving up the field by tackling them. Only players carrying the ball can be tackled and once a tackle is completed the opposition can compete for the ball.

Play stops when a try is scored, the ball crosses the side line or dead ball line, or an infringement occurs. After a team scores points, the other team restarts the game at the halfway with a drop kick towards the opposition. The team with the most points at the end wins the game.

Field and equipment

Rugby union is played on a field, known as a pitch, that should have a grassy surface, though the Laws permit the use of artificial grass, clay, sand or snow, but not permanently hard surfaces such as asphalt or concrete. The Laws do not say that the pitch needs to be flat or level, merely that the surface must be safe to play on. If either team feels that the pitch is unsafe, the referee must try to resolve the issues and must not start the match if any part of the ground is considered to be dangerous.

The playing area consists of a field-of-play, not exceeding in width and in length, and in-goal areas at each end of the field-of-play which should extend not more than but, "where practicable", at least beyond the field-of-play. Solid lines are painted on to the field to mark the sides of the pitch (touch-lines), the rear of the in-goal areas (dead-ball lines), the sides of the in-goal areas (touch-in-goal lines), the goal-lines (also called the try line), lines from each goal-line,Before the metric system was introduced, this was the line. and the half-way line. Broken lines are painted parallel to the half-way line and from it, in each half of the field, and parallel to the touch-lines and and infield from touch on each side of the field-of-play. Dash lines are also marked from (and parallel to) the goal-lines. In rugby union the edge of all lines nearest the centre of the field marks the actual boundary. Thus, touch-lines themselves are out of play, and a player standing on (or over) any part of the touch-line is regarded as being "in touch". Equally, if the ball is grounded on any part of the goal line it is regarded as having been grounded in goal (and a try is scored if grounded by an attacking player); and a ball that makes contact with the touch-line or dead-ball line is "dead".