It was more usual for rhinoceros horn cups to have been carved with designs rather than to have been left plain with the original shape of the horn retained, as with the present cup. For several other cups of this latter type see T. Fok, Connoisseurship of Rhinoceros Horn Carving in China, Hong Kong, 1999, nos. 50, 56, 60, and 64 (unhollowed). In the entry for no. 56, the author notes that cups of this type must be placed upside down in order to stand, thereby "deriving the name naihebei (helpless cup)". If offered wine in such a cup, "the guest had to finish the wine" before putting the cup down. Another plain cup in the British Museum of Art acquired from the collection of Sir Hans Sloane in 1753 is illustrated by S. Jenyns, "The Chinese Rhinoceros and Chinese Carvings in Rhinoceros Horn", TOCS, vol. 29, 1954-1955, pl. 24A, fig. 1. See, also, the plain 'full-tip' cup in the Chester Beatty Library, illustrated by J. Chapman, The Art of Rhinoceros Horn Carving in China, London, 1999, p. 70. no. 37.