It uses the 8 trigrams of the I Ching. The 8 trigrams (eight trigrams) is known as the bagua. The bagua is based on the eight main compass directions and each direction is associated with a specific energy. For example the South direction is a vibrant energy that brings things into full light. It is associated with the middle of summer. The Compass school is easy to learn and use. The only difficulty is using the compass and understanding the eight directions.