This beautiful game would be very ugly if offside didn't exist. At the World Cup, you'll see it often.

Offside calls are some of the most controversial ones in soccer. Here’s a detailed look at the rules ahead of the 2026 FIFA World Cup.

The Sporting News breaks down the offside rule, how it is enforced and why it's a part of the game.

The flag is up! We explain what that means and why one of soccer's most important rules is also one of the toughest to see ...