The _Ch´a Ching_ enumerates five other T´ang factories which supplied tea bowls, all of them inferior in reputation to the Yüeh Chou kilns. Ting Chou [Chinese] in the Hsi-an Fu,[74] in Shensi; Wu Chou [Chinese] in the Chin-hua Fu, in Chêkiang; Yo Chou [Chinese] in Hunan; Shou Chou [Chinese] in Kiangnan; and Hung Chou [Chinese], the modern Nan-ch´ang Fu, in Kiangsi, the district in which is Ching-tê Chên, afterwards the ceramic metropolis of China. Of these wares we have only the meagre information that the Yo Chou ware was of green (_ch´ing_) colour; the Shou Chou ware, yellow; and that the Hung Chou ware was a brownish colour,[75] and made the tea appear black. The Hung Chou factory is also named in the _Ko ku yao lun_,[76] which tells us that "vessels made at Hung Chou in Kiangsi are yellowish black in colour." A sixth factory, apparently of some reputation though not mentioned in the _Ch´a Ching_, is named in a poem by Tu Fu, president of the Board of Works,[77] in the T´ang dynasty, who says: "The ware (_tz´ŭ_) baked at Ta-yi is light but strong. It gives out, when struck, a sound like the plaintive note of the Chin-ch´êng jade. The white bowls of your Excellency surpass the frost and snow. In pity hasten to send one to the pavilion of my studies." Ta-yi was in the department of Ch´iung Chou, in Szechuan. The five brief dynasties which fill the interval between the T´ang and Sung periods are only known to ceramic history for two wares, the identity of which remains a matter of conjecture. The first is the _pi sê_ ware of Yüeh Chou, which has already been discussed; and the second is the celebrated but intangible Ch´ai ware. Chinese writers wax poetical over the Ch´ai ware. "Men of old," says a late Ming writer,[78] "described Ch´ai ware as blue like the sky, brilliant like a mirror, thin like paper, and resonant like a musical stone." An earlier and less hyperbolical description of it given in the _Ko ku yao lun_[79] states that it was made at Chêng Chou, in Honan, and named _ch´ai_ by Shin Tsung (of the Posterior Chou dynasty, who reigned for five years from 954 to 959); that its colour was sky blue; that it was "rich, refined, and unctuous," and had fine crackle-lines; that in many cases there was coarse yellow clay on the foot of the wares; and that it was rarely seen in the writer's time. Elsewhere[80] we read that, according to tradition, Shih Tsung, on being asked what kind of ware he would require for palace use, commanded that its colour for the future should be "the blue of the sky after rain as seen in the rifts of the clouds."[81] As early as the sixteenth century the Ch´ai ware had virtually ceased to exist, and a writer[82] of that time tells us "Ch´ai ware is no longer to be found. I once saw a fragment of a broken piece mounted in a girdle-buckle. Its colour was brilliant, and answered to the usual description of the ware, but the ware itself was thick." A century afterwards the ware was nothing more than a tradition,