CHINE, DEBUT-MILIEU DE LA DYNASTIE ZHOU (XIEME-IXEME SIECLE AV. JC.)

In J. So (ed.), Music in the Age of Confucius, Freer Gallery of Art and Arthur M. Sackler Gallery, Washington DC, 2000, pp.35-63, R. Bagley explains that "sets of bells were both aurally and visually the most prominent instruments of musical ensembles" in ancient China, but outside of China were unknown. Bells of this type were made in graduated sizes to form a set, with each bell emitting two different tones, depending on where it was struck.
A similar yongzhong bell with a flat top, bosses, and low-relief stylised serpent band is found in the Sackler Collection, illustrated by Jessica Rawson in Western Zhou Bronzes from the Arthur M. Sackler Collections, Washington D.C., 1990, vol. II B, pp. 748-749.
See also a set of graduated bells in the Freer Gallery of Art and Arthur M. Sackler Gallery, accession no. S1987.6.