The type of dragon seen on this mirror, with its distinct features including the elongated horned head, long neck, legs set wide apart, and tail wrapped around the left back leg, appears to be unique to the Tang dynasty.
It can be seen on large mirrors which began to appear around the mid-8th century. Another large eight-lobed mirror finely cast with a similar dragon, in the Donald H. Graham Collection, is illustrated by Toru Nakano, Bronze Mirrors from Ancient China, Hong Kong, 1994, pp. 238-9, no. 89.
The dragon is seen boldly striding through more numerous clouds of similar type, within a narrow raised border that is closer to the clouds in the lobes of the outer field than on the present mirror.
A similar dragon and clouds can be seen on a smaller (10.2 cm. diam.) circular mirror illustrated by Ju-hsi Chou, Circles of Reflection: The Carter Collection of Chinese Mirrors, The Cleveland Museum of Art, 2000, no. 72, and on another smaller (15.6 cm. diam.) mirror illustrated in Ancient Bronze Mirrors from the Shanghai Museum, Shanghai, 2005, pp. 256-57, no. 90, where the head of the dragon is turned backward to bite the central knob.
Acquired in Hong Kong, 1986.