Bronze Mirror with Fine Linear Design

The exact route of its excavation remains unclear. According to the testimony of Mr. Han byeong-sam, former chief director of the National Museum of Korea, the artifact had been accidentally found by soldiers digging the trenches around the present-day Nonsan area in the 1960s, which was later handed down illegally to merchant.^[2][3][4] The Christian pastor Kim yang-seon struggled to secure the relic, which is now held by the Korean Christian Museum located in Soongsil University, Seoul.^[1][4][5]

The mirror is believed to have been made around 4-3 BC when elaborate craftsmanship led to further development of bronze-made products, such as slender bronze daggers. This type of mirrors started out in Manchuria, spreading its hemisphere into the Korean peninsula and Japan.^[2][6][7] In Korea, diverse types of bronze mirrors have been found around the river basins of the Taedong River(current North Korea), Geum River and Yeongsan River.^[2]

Its diameter is 21.2 cm with a 1 cm border at the edge.^[1][4] Compared with the predecessor- coarse-surfaced mirror, this object maintains much more detailed expression on the surface, expressed with various geometric figures based on small triangular shapes.^[1][3] Given these features, the relic was named the bronze mirror with a fine linear design.

Composed of 13,000 fine lines at 0.3 millimeter intervals,^[3][8] the mirror is a representative of the Korean Bronze Age and is also considered the largest and the finest bronze mirror in the Korean peninsula in terms of patterns, molding skills, and the exquisite quality of formats.^[1][2] The mirror consists of 3 parts: inner, center and outer.^[5] The outer section is characterized by diagonal triangles with their systematic arrangement like a bell. Keeping diagonal triangle patterns at the center, the inner sphere is surrounded by 5 layers of diagonal circles.^[2] At the back, a couple of knobs are used to connect the strings with the mirror.^[1][5]

The artifact’s tin-to-copper alloy ratio is 28-72, suitable for reflecting the light similar to the function of actual mirror.^[3][8] It is believed that the object in the sense of prehistoric times had an intention of symbolizing the sun, demonstrating the religious power of the leader.^[9]

Though ancient molds for producing bronze mirrors with coarse linear designs have been found, no such molds for those with fine linear designs have ever been excavated.^[3][9] In this regard, various possibilities have been suggested. In 2007~2008, the National Museum of Korea conducted a survey on this bronze mirror with a view to going through a conservation process and analyzing its production technique. ^[5] The new research has revealed this fine linear mirror was cast in molds made from fine sand, which would require more advanced technology in precision.^[9][10]

• Prehistoric Korea
• Mumun pottery period ("Bronze Age") 1500/1000–300 BC
• Bronze mirror