How a judo contest works

1. Two athletes, one in white and one in blue, grip each other's jackets and try to throw, hold down or submit the other.
2. Ippon is the full score and ends the contest at once: a throw onto the back with speed, force and control, a hold-down of 20 seconds, or a submission.
3. Smaller scores, waza-ari and yuko, count when nobody scores ippon. When time is up the better score wins.
4. Penalties, called shido, do not count as scores, but a third one loses the contest.

How long

Four minutes of real fighting time. If the scores are level, golden score follows: no time limit, and the first to score anything wins.