graved
in the paste before firing. In the fine white specimens the design is so
delicate that it is barely visible until the vessel is filled with
liquid or held to the light. Others were covered with a coloured glaze
which serves to accentuate the design, and the most prized of these are
the yellow pieces made during the reign of Hung-Chi (1488-1505) and
Cheng-te (1506-1521).

Another wonderful variety of Chinese porcelains which made its
appearance at this period is the well-known perforated ware, commonly
spoken of, from the shape of the perforations, as "grain of rice"
porcelain, though the Chinese have exhibited consummate skill in the
manufacture of perforated pieces of all kinds. Sometimes the
perforations are left clear, but in the rice-grain pattern the incisions
are generally filled up with the melted glaze so that they become like
so many windows in the walls of the piece. We have already seen that the
Persian potters used a similar method of decoration in the 16th century,
but we are unable to say at present whether the device originated in
China or in Persia. Its use in both countries is only an additional
proof of the intercourse between eastern and western Asia.

It is only toward the end of the 16th century that we find the first
examples of porcelain decorated with colours fired over the glaze. It
seems probable that the practice grew out of the use of enamels on
metal, which had spread from Byzantium to China, and which the Chinese
developed with remarkable skill. It is important to remember that the
very nature of the glaze of Chinese porcelain, necessitating such a high
temperature to melt it, severely restricted the under-glaze palette to
cobalt-blue and the glorious but uncertain copper-red. To obtain the
rich polychromatic schemes of the potters of the West some other means
must be found, and so the device was adopted of taking a finished piece
of blue and white and decorating it further by very fusible colours
painted over the fired glaze and then attached to it by refiring at a
lower temperature equal only to that used by the enameller on metals. At
first the on-glaze or enamel colours were applied as thin washes, as in
the Ming (_San ts' ai_) three-colour decoration of green, purple, and
yellow. Then we get the Ming (_Wan-li Wu ts' ai_) five-colour scheme, in
which the same three colours are combined with an over-glaze red and all
are painted over a skeleton pattern in under-glaze blue. This