VAR: how video assistance technology for referees in sports has developed

Video assistant referees were first used in football in August 2016, and VAR was officially adopted in 2018 and has since become an integral part of the game. VAR in football is used to check goals, penalties, red cards, and offsides. The technology allows referees to review episodes and make the right decisions, avoiding mistakes that could influence the game outcome.

VAR systems are often located in the stadium where the match is played. In some leagues, the match is watched in a video room, where there are several monitors with views of the field from different angles. The VAR team consists of three people: a video referee, an assistant video referee, and a video replay operator. The video referee monitors compliance with the rules and, in case of violations, informs about the need for video replays. The assistant video referee monitors the game on the sports field. The referee can use VAR to make a decision, and VAR itself can recommend that the referee review the moment. Following the VAR's recommendation, the referee can leave their decision unchanged, or pause the game to rewatch the incident on screen, or accept the video assistant's recommendation and cancel the decision. However, the game cannot be interrupted when one side has an advantage or an attack.

Football VAR is used in the Premier League, Champions League, Europa League, and other leagues throughout Europe.

VAR in tennis is based on Hawk-Eye technology, which uses a camera system to track the lines of a tennis court and the ball movement on this court in space and time. Computers then convert this information into a virtual image that displays the ball's trajectory with a shadow to mark exactly where the ball hit the court. This technology was first used during an official match between England and Pakistan in 2001. Since 2006, Hawk-Eye has assisted in refereeing all professional tennis tournaments.

Hawk-Eye not only shows for sure whether the ball is in the court or not, but also collects statistics such as serve speed, ball spin speed, height of the ball above the net, and serve angle. Hawk-Eye was used at the Australian and American Open tournaments, as well as at the Wimbledon.

In cricket, the video assistance system is called DRS (Decision Review System). It also uses Hawk-Eye technology to track the ball. Each team can only have two Hawk-Eye reviews per inning (part of a match, set). Once the challenge is confirmed, the third referee reviews the play. Under the DRS rules, only clearly incorrect decisions are canceled; if the third referee's analysis is within the established margins of error or the situation is complicated and controversial, then the referee's original decision is applied.

VAR in volleyball was introduced in Russia at the playoff stage in 2012. Video reviews in volleyball are used to determine rule violations such as touching the net, penetration fault, and other controversial issues. Before the introduction of VAR in this sport, only the referee from the referees’ tower monitored the rules, and he also made decisions, and many disputes arose. For example, in a match in which VAR is used, even the smallest violations can be noticed: in the bronze final France – Germany (Volleyball Men's World Championship in Poland, 2014), a French player touched the net with his nose; it would have been difficult for a referee to notice this violation without VAR.

Also, VAR in volleyball can be used by coaches for tactical purposes: even if there is an obvious loss (for example, if a team member hits out of bounds while serving), the coach can take a challenge to confuse the opposing team and create a positive attitude, slow down the rhythm of the game and give your team extra time to rest. However, in one game, a team can take only 2 challenges, video reviews with the help of VAR, the decisions of which will show that the team that applied to VAR to change the result of the draw is wrong.

In volleyball, the Hawk-Eye system is also used when it is necessary to consider the ball landing in the court or out of bounds, excluding human factors. This system also determines the serve speed and other factors, collecting statistics on the game.

On June 24, 1991, the league officially approved the introduction of video replays associated with an incorrect attack on the goal. Previously, only 4 criteria were determined with the use of VAR: the puck crossing the goal line; compliance with the game time limits; whether the puck hit the referee or whether the goal was moved during the goal.

Similar to other sports using VAR, hockey rules have allowed coaches to request reviews since 2016. Challenges from coaches are mainly related to goals with goalkeeper interference or offsides. According to statistics, about 60% of challenges in hockey are successful. This is due to the fact that coaches have assistants who carefully watch the game and tell the coach whether to take a challenge.

In snooker, a photo assistant is often used, since the position of balls is restored using a shot taken before the player’s move and imposed upon the current position. Rarely, a video may be needed to clarify the situation associated with hitting the object ball with the cue ball when setting up a snooker or in the case of a touching ball.

In July 2023, VAR appeared in chess. On July 3, the International Chess Federation (FIDE) announced the use of VAR based on idChess technology in tournaments. For the first time, a video assistant arbiter at a chess competition was used at the Western Asian Youth Chess Championship in Kyrgyzstan.

Unlike video assistants in team sports, VAR idChess does not require expensive equipment and operators. How does the chess video assistant work? A mobile device is installed above the board and the game is recorded using the idChess application: a video is recorded of the players’ behavior, and the moves made are also digitized. If the arbiter missed the moment of a potential violation, he can pause the game broadcast and rewind the video to the needed episode. After reviewing this situation on video, the arbiter makes a decision based on the rules of chess and resumes the game recording.

As FIDE arbiter Muhammad Isakov noted, the introduction of an assistant referee in chess competitions helps arbiters make decisions more quickly, based on facts: “Everyone – both players and judges – expects the sport to be fair, and the VAR system only contributes to this. Already at the first competition, there were quite a lot of cases when the arbiters applied to the recording made using VAR idChess to watch the video and make a decision”.

At chess competitions, incidents with the touch – move rule have occurred more than once at the international level. For example, in the important game Polgar – Kasparov, the 13th world chess champion intended to move a piece which would deprive him of advantage, but, having thought it over, made a different move. Polgar did not make any claims, since there were no witnesses. In this case, VAR would have restored the moment of touch, which would change the decision made by the arbiter and the game outcome.

Rugby also uses VAR to assist referees in deciding fouls and handing out penalties. Watching controversial episodes in rugby is carried out with the help of TMO (Television Match Official), which uses technical means to identify the game that violates the rules. It considers such situations as whether the ball lands in or out of the playing field, whether the sanction is appropriate for the violation, and when there is doubt about whether to count a goal. The decision to use a video assistant is made only by the head referee, and video arbiters monitor following rules of the game.