The chilong is the most popular design on early glass overlays and is one of the most difficult to date by style. This color combination is rare. Many other dragon bottles exist in other color combinations, the most common being ruby-red on colorless or white glass. Because of the transparency and pale color of the overlay, where the ground shows through it, the overlay appears green and resembles the more common combination of green on a café-au-lait ground.
Compare a similar bottle with blue overlay on green glass, formerly from the Meriem Collection, sold in these rooms, 19 September 2007, lot 657; one with blue overlay on a snowflake ground in the Denis Low Collection and illustrated by R. Kleiner, in Treasures from the Sanctum of Enlightened Respect, pl. 96; another formerly in the J & J Collection and sold in these rooms, 30 March 2005, lot 20; one formerly from the collection of Jean and Saviere Pigoreau and illustrated by Robert Hall, in Chinese Snuff Bottles III, p. 13, no. 3; and two more illustrated in Snuff Bottles. The Complete Collection of Treasures of the Palace Museum, pl. 67, with dark blue overlay on green glass, and pl. 68 for an example with red overlay on colorless glass. Another unusual color combination of yellow overlay on red glass is also in the Imperial Collection, illustrated in the same publication, no. 58.