Theories concerning the development of Chinese bronzes have been presented by many scholars, the most important of whom undoubtedly are Bernard Karlgren and Max Loehr. Karlgren determined for us by aid of inscriptions those bronzes that belong to the Yin (1500–1122), and to the Chou eras (1122–771).1 Using the same catalogues of Chinese collections that Karlgren employed, and his statistical methods,2 I have reviewed the different types of bronzes and have come to a conclusion different from his. In this article, however, I shall be concerned only with Yin and early Chou vessels (first half of Western Chou, 1122–947).