This video deals with Unterhau (low strike), a strike made diagonally, from low to high, which is opposite and inverse of Oberhau.
The Basic Strikes may be made from arbitrary angles. For training we only use eight (8) specific angles, which protects the fencer like an hexagonal star. The movement of a given strike may be easy to understand, but it takes perpetual training to perform that strike really well.
to watch this video and see this technique explained in detail