There is some measure of truth of the lasting saying that sketching is the basic skill of plastic arts; at least it accords with the western art history. During the one hundred years since western skills were introduced into China, we have been paying great attention to sketching as essential technique training in academies. It is probably because of this that many sketch exercises of students have been collected and published as models. Fundamentally speaking, sketching, for the artists, is not only an essential skill, but basic creation of art.