Theodore Roosevelt became a brown belt in Judo during his administration and actor James Cagney was a black belt in Judo. So, you're at the Judo Tournament. Hopefully the following will be an easy introduction to the rules that will help you to understand the tournament. Quite simply they are trying to 1. There are hundreds of variations of throwing techniques.
Some throws use mostly legs, some mostly arms, some a combination of arms, legs, and torso.
Some throw their opponent over their own hips, shoulder, or back. They can also sweep the opponent's feet out from under him, or they can drop down and throw the opponent over their own fallen body. Strangle holds are only allowed on players 13 years old or older. Arm locks can only be used if the player is at least 17 years old. Although strangles and arm locks may seem dangerous, the players are trained to know when they are in danger, and will submit by tapping either the mat, or the opponent, twice, before any damage is done.