But there is another and perhaps even a more important reason for our trying to form some idea of what the earliest wares of the Chinese were like: unless we make some such endeavour we shall find it impossible to understand the later history of porcelain in that country. One point must be specially borne in mind when we are attempting to follow the order in which fresh styles and designs were introduced in China. When a new method of decoration had been adopted and had come into general use--the introduction of underglaze blue in early Ming times, and that of coloured enamels at a later period, are cases in point--this did not involve the abandonment of the older styles. There was a constant effort to maintain the old methods, and in the most flourishing times of the emperors Kang-he and Kien-lung, the series of great men who had charge of the imperial works at King-te-chen, some of them practical potters themselves, were constantly occupied with the problems of reproducing the glazes, if not the pastes, of the earliest wares. During the reign of Yung-chêng (1723-1735), perhaps the culminating period in the history of Chinese porcelain, when Nien Hsi-yao was superintendent, a list was drawn up of fifty-seven varieties of porcelain made at King-te-chen. In this list the titles of all the old wares of the Sung dynasty are to be found, and to them the place of honour is evidently awarded (Bushell, chap. xii.). The names of some of these old wares, the Ko yao and the Kuan yao, for instance, are applied to porcelain in common use at the present day, an attribution based on the greater or less resemblance of this modern ware to the Sung porcelain, at least in the matter of the glazes. It is only quite of late years that we in Europe have been able to make any clear distinction, not only between the different classes of Chinese porcelain, but between what is Chinese and what is not. A few years ago the most characteristic porcelain of Japan was classed as Chinese, while on the other hand Corea and even local English factories were credited with porcelain made and decorated in one or other of the former countries.