The number nine is one of the most auspicious numbers in Chinese numerology, and as it is the highest single digit, it is often associated with the Emperor. This is evident on court robes of the highest rank, which often feature nine dragons, as opposed to those of lower rank which typically feature eight or five.
The jade carver's skill in working the natural irregular form of the present boulder to convey an overall ethereal theme of the dragons emerging out of dense clouds above swirling waves is immediately noticeable. The treatment of the whirlpool on the underside of the vessel appears readily on jade carvings dating to the Ming dynasty, such as the white jade mythical dragon/tortoise-shaped water container included in the exhibition, Arts from the Scholars Studio, Hong Kong, 1986, p. 158, no. 131. This decorative motif continued well into the Qing dynasty, and appears on a jade brush washer carved with dragons, clouds and waves, in the collection of the Palace Museum, Beijing, illustrated in Zhongguo Yuqi Quanji, Hebei, p. 226, no. 333, where it is dated to the middle Qing dynasty.
Perhaps one of the closest comparisons may be made to the much larger (32 cm.) Qianlong period imperial white and russet jade brush washer from the collection of Alan and Simone Hartman, sold in our Hong Kong rooms, 27 November 2007, lot 1504. Both the Hartman brush washer and the present example are carved with a very similar whirlpool of waves forming the base, and both are deeply carved with dragons amidst clouds on the sides. It is also interesting to note that both examples are carved retaining the natural shape of the boulder.