Previously sold Sotheby's London, 11 December 1990, lot 325.
A blue and white flask of the same pattern from the Wu Lai-hsi Collection is illustrated by Honey, The Ceramic Art of China and Other Countries of the Far East, pl. 87b, where it is catalogued as 15th century, but is in fact more closely related to 18th century examples, and may also have had a Yongzheng mark at one time. Another closely related flask with a Yongzheng mark in the Palace Museum, Beijing, is illustrated in Kangxi, Yongzheng, Qianlong, p. 173, pl. 2. A comparable example decorated with yellow enamel as a ground colour is in the Baur Collection, illustrated by J. Ayers, Catalogue, vol. IV, no. A573.
Compare this example with the Ming dynasty prototype of early 15th century date decorated with a single bird perched on a branch on each of the facing sides in the Percival David Foundation, illustrated by R. Scott, Elegant Form and Harmonious Decoration, p. 42, no. 29. The Ming dynasty flask is illustrated again by R. Scott, Percival David Foundation of Chinese Art: A Guide to the Collection, p. 73, no. 61, where the author notes the derivation of this shape from Syrian glass.
Reign marks on Imperial porcelains were removed for one of two reasons: either in an attempt to deceive (in this case to pass the flask off as 15th century rather than 18th century); but we also know that works of art removed from the Imperial Palace before the fall of the Qing dynasty often had the reign marks removed as a matter of course as the possession of Imperial wares were forbidden outside the palace.