A ruck forms around a ball on the ground. Law 15 explains the conditions for formation and how players may join legally.
When a ruck exists
A ruck forms when at least one player from each team is in contact with an opponent, on their feet and over the ball on the ground. The ball must be on the ground; contact between players alone is not enough if any of these conditions is missing.
How to join
Each team has its own offside line, parallel to the goal line and through the hindmost point of any player participating in the ruck. A player may join only from behind their team’s line. They may join alongside the hindmost player, but not in front of them. An arriving player must stay on their feet and bind onto a teammate or opponent before, or at the same time as, making contact with any other part of the body.
Stay on the correct side
After joining, a player must stay bound and endeavor to remain on their feet throughout the ruck. In general, once a ruck has formed, players may not handle the ball; the exception is a player who had their hands on it before formation and stayed on their feet. Check the other provisions of Law 15, including global law trials identified by World Rugby, for the applicable competition.
Read World Rugby Law 15 (official source checked 16 October 2026).