https://qz.com/1305673/world-cup-2018-video-assistant-referee-var-debuts-and-goal-line-technology-glt-is-back-heres-the-difference/

The 2018 World Cup just kicked off in Russia, with the first game between the hosts and Saudi Arabia in Moscow.

This year’s tournament will be the first to use what’s called Video Assistant Referee (VAR) to help on-field referees with contentious match decisions. The concept is not unlike setups used in many US professional sports, where a group of referees review plays and calls made on the field from a variety of angles to see whether the ruling made on the field was the correct one. Leagues around the world, including the US’s Major League Soccer, Germany’s Bundesliga, and soon, England’s Premier League, use varying versions of the setup. For the World Cup, a central team of four referees will watch each game from a room in Moscow to determine whether referees made the right call on offsides, fouls, and other decisions.