Active referee certification (all levels) requires current membership in USA Judo, background investigation (clear and max 2 years old) and current compliance with Safesport.
Together with the new refereeing rules, implemented for the first time on the occasion of Grand Prix Portugal 2022, come three new refereeing gestures/signals:
For a video link, click here
Here's a link to the new judo rules posted by the IJF for 2022 to 2024.