Chenghua Chicken Cup

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For centuries now, scholars have written on the subject of the illustrious 'Chicken Cup' first produced during the reign of the Ming emperor Chenghua (1465-1487).  Almost every book covering the subject of Chinese porcelain mentions the rare cup.  It is reported that there are only fifteen known in existence, mostly in museums, and only three in private hands. 

Made strictly for the Imperial household, it was said that the later Ming emperor, Wanli (1573-1620), was very fond of the cup.  It is also documented that a pair was known to fetch as much as the equivalent of $10000 US dollars during the end of the Ming reign.  Because of the popularity, copies were produced during various reigns of the later Qing dynasty with both the current reign mark and the apocryphal (or spurious) reign mark.  The latter proving problematic for centuries to the porcelain connoisseur.

It was a well know fact that there were corrupt official within the Imperial Palace, and just as well known that on occasion a piece was 'smuggled' out of the Imperial kiln, rather than be destroyed, should it have a minor flaw.  An alliance between the corrupt officials and the head of the kiln created an underground that channeled an occasional piece of Imperial bound porcelain to a non-imperial destination for a nice profit.

Though this practice has been documented by both scholars and historians, there has yet to be an authenticated example of a Chenghua chicken cup originating from this source.  This cup provides an excellent example.

Native versus Imported Cobalt

It's very important to fully understand the properties of native Chinese cobalt, since it offers one of the best clues to determining authentic Chenghua porcelain.  Here is a brief introduction to the subject.

Qing copies show the underglaze cobalt as a much deeper, brighter blue.  There are two varieties of this imported blue.  One is known as Mohammedan (or Persian) Blue¹, and the other known as Sumatran Blue².  There is little to differentiate between both of these imported  pigments.  What is key, however, is that both were unavailable (or extremely scarce) during the Chenghua reign, forcing the use of the paler native Chinese cobalt.  Microscopic examination of the properties of the native cobalt reveal a presence of manganese, giving a grayish green tone to areas of accumulation. This property is not present on later Qing copies (fig 2) since the imported cobalt, being of superior quality and brightness, only required one even layer of application.

¹ Mohammedan Blue - also called hui hui ch'ing.

² Sumatran Blue - also called su-ma-li, su-ma-ni, or su-ni-p'o blue.

Flaws and discoloration

_{To begin with, copies of Imperial ware are made to perfection.  Even a slight flaw would immediately flag it as not being of Imperial quality.   It would not be logical for a counterfeiter to produce a copy of the well known cup with any visible imperfection.  The example to the right shows the reign mark being darker in some areas, caused by a thicker application of cobalt.  In contrast, the other areas appear much lighter and pale. Because of the pale (weak) native cobalt used during the reign, it was often applied generously in an attempt to create a richer, brighter blue.  The subsequent result would produce the effect seen here.  Though a slight imperfection, a definite sign of authenticity.}

(Fig 1)

Original Reign Mark.

Decoration

Figure 2 shows an example of a later Qing copy. Noticeably different from the authentic Chenghua style is the use of more vibrant enamel coloring and bright blue underglaze.  This is definitely not the trademark of original Chenghua,  specifically in the underglaze blue areas where the paler native cobalt was used.  

(fig 2)

Brighter colors of a Qing copy.

Measurements

Most original Chenghua chicken cups have the exact same shape and measurements.

On the average, they are 8.2 centimeters. in diameter, 3.4 centimeters in height. The lip has a slight flair (fig. 3). The depth measures 2.8 centimeters to a very thin 2 mm. bottom. Many of the Qing copies are lacking the flare to the lip.  

Another property (or characteristic) is a slight grinding to the lip.  There is some debate as to the purpose for this, but it appears to have been done during manufacture.  Only a few specimens are known to exist.  This cup does not have that property. 

The footrim is wedge shaped with the inner surface being more vertical to a depth of 4 mm.  The outer diameter of the footrim averages 4.3 centimeters, with the inner diameter averaging 3.8 centimeters.  Many of the Qing copies have little discoloration to the biscuit, as compared to the authentic (fig 4).

The weight is 1.6 ounces (Avoir) which translates to 45.4 grams.

(fig 3)

(fig 4)

Physical Properties

History and documentation on the physical properties of the cup agrees to a thin, delicate body.  This cup has that property, with the average potting being 2 to 3 mm. thick between the lip and the base.  Looking down, one can visibly make out the placing of the reign mark through the body.  When holding it to the light (Fig 5), it appears almost transparent.  

Microscopic examination of the inner surface reveals signs of wear to the cup.  The wear is not manufactured.

I would be suspicious of any Chenghua chicken cup pronounced authentic that clearly displays the properties of Mohammedan or Sumatran blue, and does not have the very thin base and exact measurements.

(fig 5)