In reading the list of T’ang’s innovations the reader will perhaps be puzzled by the varieties of black decoration which are included. Before attempting to explain them it will be best to review the different kinds of black found on Chinese porcelain of the Ch’ing dynasty. There is the high-fired black glaze, with hard shining surface likened to that of a mirror and usually enriched with gilt traceries. This is the original _wu chin_ described by Père d’Entrecolles.[434] The other blacks are all low-fired colours of the muffle kiln applied over the glaze and ranking with the enamel colours. They include at least five varieties: (1) The dry black pigment, derived from cobaltiferous ore of manganese, applied like the iron red without any glassy flux. (2) The same pigment washed over with a transparent green enamel. This is the iridescent greenish black of the _famille verte_, and it continued in use along with the _famille rose_ colours in the Yung Chêng and Ch’ien Lung periods and onwards to modern times. (3) A black enamel in which the same elements--manganese black and copper green--are compounded together. This is the modern _wu chin_, of which a sample in the Sèvres Museum (from the collection of M. Itier) was described by Julien[435] as “noir mat; minerai de manganese cobaltifère et oxyde de cuivre avec céruse.” It appears on modern Chinese porcelain as a sticky greenish black enamel, inferior in depth and softness to the old composite black of the _famille verte_; but for all that, this is the _yang wu chin_ (foreign black) of the Yung Chêng and Ch’ien Lung periods. In the days of T’ang Ying it was a far superior colour. (4) A mottled greenish black occurs as a monochrome and as a ground colour with reserved discs enamelled with _famille rose_ colours on the exterior of two bowls in the British Museum, both of which have the cyclical date, _wu ch’ên_, under the base, indicating the year 1748 or 1808, probably the latter. (5) An enamel of similar texture but of a purplish black colour is used on a snuff bottle in the same collection to surround a figure design in underglaze blue. This piece has the Yung Chêng mark in red, but from its general character appears to be of later date. In the list of T’ang’s innovations there is _yang wu chin_ (foreign black), which is doubtless the same as the _hsi yang wu chin_ (European black) of Hsieh Min’s list. It is clear that this is something different from the old green black of the _famille verte_ porcelain, and we can hardly be wrong in identifying it with the _wu chin_ enamel described above in No. 3. Compared with the original mirror black _wu chin_ glaze this enamel has a dull surface, and we can only infer that the term _wu chin_ had already lost its special sense of metallic black, and was now used merely as a general term for black.