2026. 8. 1. 19:36ㆍ취미생활/축구
Hello.
Today's post breaks down one of the most debated rules in soccer: the offside rule.
When exactly does a player get called offside?
If you've ever watched a match and wondered why a perfectly good-looking goal got chalked off, you're not alone. Even seasoned commentators disagree on offside calls in real time, which says a lot about how tricky this rule can be.
The offside rule has actually shaped the sport itself. Without it, attackers could simply camp out near the opponent's goal waiting for long balls, turning matches into a very different, less dynamic game. Let's walk through what the rule actually says, how it evolved, and the technology now used to enforce it.
Origins and the Basic Rule
The offside rule is written into Law 11 of soccer's official rulebook, the Laws of the Game. A player is in an offside position if, at the moment the ball is played to them, they are nearer to the opponent's goal line than both the ball and the second-last opponent.
Being in an offside position by itself is not an offense. The player has to become actively involved in play, by interfering with an opponent, touching the ball, or clearly gaining an advantage from that position, before the referee blows the whistle.
For example, a forward standing in an offside position who never touches the ball or affects the play won't be flagged. But the same player receiving a pass, or blocking the goalkeeper's line of sight, will be called offside.
One detail that trips people up: the goalkeeper usually counts as one of the "two" defenders needed to set the offside line. In most situations, that means the offside line is set by the goalkeeper plus the last outfield defender.
How the Rule Has Evolved
The concept of offside dates back to 1863, when The Football Association (FA) in England codified a unified set of rules for the sport. Under the earliest version, an attacker needed at least three defenders between themselves and the goal to stay onside.
That requirement changed significantly in 1925, when the International Football Association Board (IFAB) reduced the number of required defenders from three to two, a shift widely credited with opening up more attacking play.
In 1990, the law shifted further in favor of attackers: a player level with the second-last defender is now ruled onside rather than offside. This "level equals onside" principle is still in effect today.
A key clarification came in 2003, when IFAB formally wrote "active involvement in play" into the law. Simply standing in an offside position was no longer, by itself, an offense, a distinction that forms the backbone of how offside is judged today.
VAR and Semi-Automated Offside Technology
Because offside calls often come down to a split-second and mere centimeters, getting them right with the naked eye is genuinely difficult. To address this, Video Assistant Referee (VAR) review was officially introduced at the 2018 World Cup in Russia.
VAR allows officials to review goals or scoring chances where offside may have played a role. In its early years, though, reviews could take several minutes, and exactly where to draw the offside line became a recurring source of controversy.
To cut down on that controversy, FIFA rolled out Semi-Automated Offside Technology (SAOT) at the 2022 World Cup in Qatar. The system uses 12 tracking cameras mounted under the stadium roof to follow the ball and 29 data points on each player in real time, generating a 3D animation that shows whether a player was offside.
SAOT has since been adopted by the UEFA Champions League and Italy's Serie A, and the English Premier League officially rolled it out starting with the 2024-25 season. Speed and accuracy have improved noticeably, but razor-thin offside calls still spark plenty of debate among fans.
