Judo is a martial art that focuses on using the opponent's power and momentum to throw them. Submissions are legal in judo, which are techniques that force the opponent to tap out or submit. These submissions include joint locks, choke holds, and strangle holds. It is important to remember that the goal of judo is to throw the opponent, so submissions should be used sparingly and only when necessary. Submissions are also prohibited if they are dangerous or cause permanent injury. Proper judo technique and etiquette must be followed when using submissions.