This type of bell, nao, was supported on its hollowed shank and was struck with a mallet to produce the tones.
Large nao of this type have been found in excavations in southern China, in the lower Yangzi river basin, indicating that the south had developed its own bronze technology independent of the northern bronze centers, such as Anyang. Most of the early nao bells found at Anyang are small and in sets of three. See J. So, Eastern Zhou Ritual Bronzes from the Arthur M. Sackler Collections, The Arthur M. Sackler Foundation, 1995, p. 439, fig. M13, for a set of three from Anyang Dasikongcun dated to late Shang (Anyang period). They are decorated with taotie masks cast in low relief. As nao bells developed in the south, the taotie mask became more and more stylized until it was dissolved into a ground of scrolls with only large eyes still visible, such as those illustrated ibid., p. 440, figs. M17 and M19, as well as by R. Bagley, Shang Ritual Bronzes in the Arthur M. Sackler Collections, 1987, p. 119, fig. 167.
The present bell is representative of a slightly later stage, where rows of bosses are now a main decorative motif. A bell of this type with similar bosses and scroll bands from Zhejiang Changxing Xi'an, dated Shang or early Zhou is illustrated in Eastern Zhou Bronzes from the Arthur M. Sackler Collections, ibid., p. 393, fig. 80. Another is illustrated in Miho Museum: South Wing, 1997, no. 79 and and another found in a group of ten nao unearthed together in 1993 in Ningxiang, Hunan province, is illustrated by J.F. So, ed., Music in the Age of Confucius, Freer Gallery of Art and Arthur M. Sackler Gallery, 2000, p. 49, fig. 2.18, and is dated 12th or 11th century BC. Although of varying size and decoration, pitch measurements reveal that the A-tones of this group of bells are spaced at very accurate semitone intervals.