As for the finer Ko wares, which appear to have been indistinguishable from the Kuan, we may look for them in the group described on p. 65, and in such beautiful pieces as that illustrated on Plate 19, a vase of fine oval form with delicate grey glaze of faint bluish tone boldly crackled. The solid quality of the glaze of this last specimen and the texture of the surface, which is smooth but lustrous, suggest some natural substance such as the shell of an egg or a smooth polished stone rather than an artificial material. The colour perhaps more truly answers the description "egg white" (_luan pai_) than any other Sung glaze which I have seen. Plate 20 illustrates another choice example but with a yellower tone of glaze; and a large square vase in the Freer Collection[147] with thick, misty grey glaze showing a faint tinge of red, which recall the _sê ch´ing tai fên hung_ of the Kuan ware, was shown in the New York exhibition of 1914. All these three specimens have a dark reddish brown body of fine close grain, and their glaze is very thick and unctuous with a tendency to contract into thick wax-like drops under the base. From certain passages in the Chinese works it appears that a revival of the Ko yao took place in the Yüan dynasty, if indeed the manufacture had not been continuous. The _Ko ku yao lun_, for instance, under the heading of Ko yao, states that the "ware recently made at the end of the Yüan dynasty was coarse and dry in body and inferior in colour." In the _Po wu yao lan_[148] we read that "certain Ko wares made in private factories took their clay from the Phœnix Hill" (at Hang Chou, where the Kuan potteries were located), and the _T´ao lu_[149] definitely states that clay was brought from Hang Chou for this later Ko ware. Add to these the remark in the _Ko ku yao lun_ on the subject of Kuan ware[150]--"all the imitations which are made at Lung-ch´üan are without crackle"--and it is clear that the Lung-ch´üan potters in the fourteenth century were busy copying both the Kuan and Ko wares, and that to obtain a closer resemblance to the former they actually sent to Hang Chou for the red clay which would produce the "brown mouth and iron foot." The alleged absence of crackle would indicate a departure from the original Ko methods, but we are at liberty to doubt the universal application of such sweeping statements, and I ventured to suggest[151] that a remarkable bowl in the British Museum was a Yüan example of Ko ware, because, in spite of its Ko crackle, it corresponds so closely to the other points in the descriptions of this make. In any case, there is little doubt that it belongs to an early period of manufacture. [Illustration: PLATE 20. Deep Bowl of reddish brown stoneware with thick, boldly crackled glaze. Ko ware of the Sung dynasty. Height (without stand) 4 inches. _Eumorfopoulos Collection._ ]