A unique feature of this Qianlong’s (1735-1796 AD) pair is the very thick and heavy body (about 2 to 3 times thicker than usual porcelain wares of this size). They are made of very fine clay. Also very unusual is their shape somewhat resemble ancient silver bullions. The inner bottoms show various degrees of wear with long crackle lines on the glaze, due to almost 300 years of use. The glaze is evenly applied with unctuous surface, and without the shine of newly fired porcelain. The glaze collects at concave lines to give bluer color, but drain thin at protrude lines to show very light blue color. These are some common features of many Qianlong monochrome wares. The unique combination of intense underglaze cobalt blue of Qianlong and the overlaying blue glaze causes the mark to become blackish blue. Later imitations of Qianlong sky blue usually have lighter marks; a feature distinguishes the genuine from the fakes. The last word of the mark (Zhi, ?, making) is unique; this style also appear on several other Qianlong imperial wares. Please consult the Chinese description below for more details. From Dr. Robert I-San Lin (#140 A&B), a senior Chinese artwork appraiser, whose grandfather was a major Chinese antique merchant in early 1900s. (Dr. Lin’s bio, in Journal of Authentication of Artworks, 2015, available on request). Brought to California in 1960s.