The potter Guo Yunshan made a small group of bottles of this ribbed form, such as the example from the J & J Collection sold in Hong Kong rooms, 25 April 2004, lot 881.
Undecorated Yixing ware is a delightful substance and since it is both plain and susceptible to surface transformation through use, patination is a major part of its appeal. The patina on this bottle is very attractive, with a lovely textural dimension added to the plain, chocolate-brown surface through a century or more of use. The mottled, darker brown markings of the patina, caused by the natural oils from the hand, immensely enhance the surface and accentuate the form. Yixing is somewhat like organic substances such as wood and bamboo in this respect - a quality which was not lost on its target audience, who valued the surface transformation on Yixing as they would on an ancient gourd or bamboo carving.