Transparent Treasured Mirror
of the Western Han Dynasty

This Western Han mirror (206 b.c.e. – 24 c.e.) is called a transparent treasured mirror. Skillful artisans made this precious Chinese national treasure for the iClick to enlargemperial court. The bronze mirror’s slightly convex face and smooth, bright, clear surface give no clue to the mystery hidden within: When the sun shines on the face of the mirror, it passes through—revealing the mirror’s previously invisible pattern by reflecting it on a white wall. Ancient people believed that the transparent treasured mirror could drive out evil spirits, and regarded it as a supernatural being. Even today, the effect is mysterious and enigmatic.

Decorated bronze discs thought to be mirrors were found in northwest China between 2000 and 1750 b.c.e. At first, and always to some degree, their purpose was to reflect not only one’s face, but one’s heart and soul. In 658 b.c.e. an entry in the Tso Chuan, China’s oldest narrative history, described a certain individual with the words "Heaven has robbed him of his mirror"— that is, made him blind to his own faults.

The mirror also represents something in which all knowledge is reflected. Zhuang Zi, a prominent Daoist philosopher in the Eastern Zhou Dynasty (770–256 b.c.e.), wrote, "The heart of the sage is quiet; it is a mirror of Heaven and earth." The mirror holds and reflects the rays of the sun, warding off evil and lighting the eternal darkness of the tomb.

Today, only four original transparent treasured mirrors remain, and they are in the Shanghai Museum. The craft of making this compelling mirror was not handed down from ancient times, and scholars have argued about how it was made for about a thousand years. Although the exact method of fabrication has never been discovered, in 1975 Chinese scientists revealed a thousand-year-old secret: The mirror’s surface has precise microscopic "peaks and valleys," invisible to the naked eye. Amplification of the peaks and valleys by light induces a difference in reflection resulting in the formation of an image.