The shoulder in, referred to as the "aspirin of riding art" by Oliveira, has a fundamental meaning in the Academic Art of Riding. In between shoulder in and quarter in the rider straightens up the horse - and sends it forward towards the point of weight. In this movie, Bent Branderup is explaining why and how the shoulder in is needed to develop a horse's forward and stepping towards the riders hand, and why the content of the excercise is not the sidewarts stepping. Of course he will offer as well a deeper insight in historical facts relating to the old masters as having a close look at biomechanics in the shoulder in movement. Some practical advice for your own work at home is completing the overview of this important topic.