Officials and offences

Main articles: Rugby union match officials and Laws of rugby union

There are three match officials: a referee, and two assistant referees.^[75] The latter, formerly known as touch judges, had the primary function of indicating when the ball had gone into "touch"; their role has been expanded and they are now expected to assist the referee in a number of areas, such as watching for foul play and checking offside lines.^[75] In addition, for matches in high level competitions, there is often a television match official (TMO; popularly called the "video referee"), to assist with certain decisions, linked up to the referee by radio.^[76] The referees have a system of hand signals to indicate their decisions.^[77]
Common offences include tackling above the shoulders, collapsing a scrum, ruck or maul, not releasing the ball when on the ground, or being offside.^[78] The non-offending team has a number of options when awarded a penalty: a "tap" kick, when the ball is kicked a very short distance from hand, allowing the kicker to regather the ball and run with it; a punt, when the ball is kicked a long distance from hand, for field position; a place-kick, when the kicker will attempt to score a goal; or a scrum.^[78] Players may be sent off (signalled by a red card) or temporarily suspended ("sin-binned") for ten minutes (yellow card) for foul play or repeated infringements, and may not be replaced.^[78]
Occasionally, infringements are not caught by the referee during the match and these may be "cited" by the citing commissioner after the match and have punishments (usually suspension for a number of weeks) imposed on the infringing player.^[79]

Replacements and substitutions

During the match, players may be replaced (for injury) or substituted (for tactical reasons).^[46] A player who has been replaced may not rejoin play unless he was temporarily replaced to have bleeding controlled; a player who has been substituted may return temporarily, to replace a player who has a blood injury or has suffered a concussion, or permanently, if he is replacing a front-row forward.^[46] In international matches, eight replacements are allowed; in domestic or cross-border tournaments, at the discretion of the responsible national union(s), the number of replacements may be nominated to a maximum of eight, of whom three must be sufficiently trained and experienced to provide cover for the three front row positions.^[46][80]
Prior to 2016, all substitutions, no matter the cause, counted against the limit during a match. In 2016, World Rugby changed the law so that substitutions made to replace a player deemed unable to continue due to foul play by the opposition would no longer count against the match limit. This change was introduced in January of that year in the Southern Hemisphere and June in the Northern Hemisphere.^[81]

Equipment

A synthetic rugby ball

Main article: Rugby union equipment

The most basic items of equipment for a game of rugby union are the ball itself, a rugby shirt (also known as a "jersey"), rugby shorts, socks and boots. The rugby ball is oval in shape, (technically a prolate spheroid), and is made up of four panels.^[82] The ball was historically made of leather, but in the modern era most games use a ball made from a synthetic material. The WR lays out specific dimensions for the ball, 280-300mm in length, 740-770mm in circumference of length and 580-620mm in circumference of width.^[82] Rugby boots have soles with studs to allow grip on the turf of the pitch. The studs may be either metal or plastic but must not have any sharp edges or ridges.^[83]
Protective equipment is optional and strictly regulated. The most common items are mouthguards, which are worn by almost all players, and are compulsory in some rugby-playing nations.^[84] Other protective items that are permitted include head gear; thin (not more than 10 mm thick), non-rigid shoulder pads and shin guards; which are worn underneath socks.^[83] Bandages or tape can be worn to support or protect injuries; some players wear tape around the head to protect the ears in scrums and rucks. Female players may also wear chest pads.^[83] Although not worn for protection, some types of fingerless mitts are allowed to aid grip.^[83]
It is the responsibility of the match officials to check players' clothing and equipment before a game to ensure that it conforms to the laws of the game.^[83]