Shih Tzu how to distinguish pure or impure

How can a Shih Tzu be identified as pure or impure? A purebred adult Shih Tzu is no more than 16cm tall at the shoulder and weighs no more than 7kg; Shih Tzu is petite, with a well-proportioned structure, a double coat, and dense, lustrous hair; a good-looking Shih Tzu has a full face, large, round eyes, and dark pupils. The Shih Tzu is a small dog with a long coat and a small, delicate body, even if the adult Shih Tzu is less than 16cm tall at the shoulder and weighs no more than 7kg. In particular, the lines on the back are parallel, and if they are curved or not parallel, it means that the Shih Tzu is out of shape. Purebred Shih Tzus have full faces, large round eyes, and large eye spacing, normal eye depth, and dark pupils, although some Shih Tzus may also have blue pupils, but relatively few. In addition, they have a black muzzle and a short, wide muzzle. The purebred Shih Tzu’s tail is slightly longer from the elbow to the shoulder than from the elbow to the ground. The coat of the Shih Tzu is a double coat that covers the entire body and is very rich and dense, with a long, smooth coat that allows for a slight undulation.