Vessels of this type were derived from nomadic leather pouches. A very similar flask is illustrated by R. Krahl in The Anthony de Rothschild Collection of Chinese Ceramics, The Eranda Foundation, vol. 1, 1996, pp. 50-51, no. 27, and another in the National Trust, Ascott Collection is illustrated by M. Medley, T'ang Pottery and Porcelain, London, 1981, p. 131, no. 125.