The present pair of vases seems to be extremely unusual and no comparable examples in porcelain or metalwork appear to be published. The prototype of this form appears to be the Tibetan ritual water vessel of bhumpa form, such as one exhibited in the National Palace Museum, A Special Exhibition of Buddhist Gilt Votive Objects, Taipei, 1995, no. 12, with similar wide rounded shoulders and lobed columnar necks on splayed feet. The addition of a lotus-petal molded hemispherical mouth, however, appears to be a new innovation and the present pair would also have most likely had domed covers which in turn may have had lobed or reticulated decoration. During the early Qing period, traditional forms of Tibetan ritual vessels were frequently replicated or re-interpreted in different media, particularly in enameled gold or gilt-bronze, cloisonné and porcelain. Several such vessels in the National Palace Museum were exhibited in Enamel Ware in the Ming and Ch'ing Dynasties, Taipei, February 1999, including no. 35, a cloisonné and gold doumuhu ewer; no. 36, a cloisonné and gilt-bronze covered butter-jar; no. 60, a cloisonné kundika, and no. 98, a Yongzheng-marked painted enamel and gilt-bronze bhumpa ovoid vessel.
The finely molded lobed lotus petals on the mouths of the present vases are also distinctive and probably derived from enameled gilt-copper bowls produced in the Kangxi period, see ibid., no. 89, a bowl with cover, as well as another version in the Palace Museum, Beijing, illustrated in The Complete Collection of Treasures of the Palace Museum - 43 - Metal-bodied Enamel Ware, Hong Kong, 2002, no. 178, with unusual lobed bowl-stand. Another highly unusual feature of the vases is that their blue enamel reign marks are written in the style of typical underglaze-blue seal marks reserved against a turquoise enamel ground, rather than in the calligraphic style of blue enamel marks written over the turquoise ground and enclosed in double-line squares; compare The Complete Collection of Treasures of the Palace Museum - 39 - Porcelains with Cloisonné Enamel Decoration and Famille Rose Decoration, Hong Kong, 1999, no. 91 (with six-character seal mark) and nos. 27 and 110 (with four-character seal marks).