Schutzhund is a german word meaning "protection dog."  It started in the early 1900's as a test for working German Shepherds to determine which dogs could be used for breeding and had true working abilities. 

It is made up of three (3) parts: Schutzhund 1 (SchH 1), Schutzhund 2 (SchH 2), and Schutzhund 3 (SchH 3).The three (3) phases consists of tracking, obedience and protection.  They are judged on a hundred (100) point scale with a minimum passing being 70%.

I am going to address the protection phase because many people are misled to believe that this trains a dog to be mean and aggressive.  The protection phase is a relationship between the dog and the handler/trainer.  The dog must never bite the trial helper (helpers assist the judge during a trial with bite work) unless either the dog or handler is attacked.  Then the dog must attack fully without hesitation.  The difference between aggressive and disciplined is the dog must stop biting the sleeve on command from his handler.

Before a dog can compete for a SchH 1, she must pass a temperament test called a BH (Begleithundprufung which translates "traffic-sure companion dog test").  The BH tests for obedience, surroundings, loud noises, different people and dogs, and traffic.

IPO competitions also include 3 phases, like Schutzhund.  Various breeds are allowed to compete in IPO competitions, i.e. German Shepherds, Dobermann Pinschers and Boxers.