Who is responsible for enforcing the MTR during a tournament?

The head judge is the primary individual responsible for enforcing the Magic Tournament Rules (MTR) during a tournament. This role entails overseeing the event, ensuring that all players adhere to the rules and procedures outlined in the MTR, and making key decisions regarding any rule violations or disputes that may arise.

The head judge has the authority to issue penalties, manage the flow of the tournament, and resolve any issues that could affect the integrity of the competition. While assistants play a crucial support role by handling various logistical aspects and helping to enforce specific rules under the head judge's oversight, the ultimate responsibility lies with the head judge. Players must also adhere to the rules, but they are not in a position to enforce them. Event organizers are responsible for the overall event setup and administration but rely on the head judge to manage the gameplay aspects of the tournament.