All 12 Makers of the Jagyeokru at Changgyeonggung Palace Have Been Identified

Cultural Heritage Conservation Science Center Completes Conservation Treatment of Changgyeonggung Jagyeokru After 1 Year and 7 Months
Removal of Contaminants and Material Reinforcement "High Possibility of Casting Using Wax Casting Technique"

Jageokru of Changgyeonggung after preservation treatment

[Asia Economy Reporter Lee Jong-gil] The Jagyeokru was the standard clock of the Joseon Dynasty. It automatically indicated the time according to the increase or decrease of water. The Jagyeokru made by Jang Yeong-sil in 1434 under King Sejong's order has not been passed down. Only three pieces of Pasuho and two pieces of Susuho, parts of the Jagyeokru remade in 1536, remained at Borugak in Changgyeonggung Palace. Pasuho refers to the bronze jar that sends water, and Susuho refers to the bronze cylindrical jar that receives water.

On the upper part of the left Susuho, there is an embossed inscription made at the time of casting. The positions and names of twelve people who participated in the making of the Jagyeokru are engraved vertically. These include Yeonguijeong Kim Geun-sa (1466-1539), Jwauijeong Kim An-ro (1481-1537), Uchanseong Yoo Bo (1470-1544), Gongjo Champan Choi Se-jeol (1479-1535), U Tongrye Park Han (?), Cheonmunhakgyosu Shin Bo-sang (1496-1570), Sogyeokseo Chambong Kang Young-se (?), and Cheonmun Iseupgwan In Gwang-pil (?). The remaining four names were worn out and unknown but were later revealed through preservation treatment. They are Saheonbu Jibui An Hyeon (1501-1560), Saboksi Jeong Igongjang (?), Saheonbu Jangryeong Kim Su-seong (unknown~1546), and Jangakwon Jubu Chae Mu-jeok (1500-1554).

Inscription on the sorghum jar (left) before preservation treatment

The Cultural Heritage Administration’s National Research Institute of Cultural Heritage Conservation Science Center announced on the 22nd that it has completed the preservation treatment of the Changgyeonggung Jagyeokru (National Treasure No. 229) after one year and seven months. The Jagyeokru had previously undergone light preservation treatment such as dust removal and oil application when it was moved inside Deoksugung Gwangmyeongmun for exhibition. However, this method could not prevent corrosion and damage to the bronze material, so it was moved to the Conservation Science Center in June 2018 for preservation treatment.

The Conservation Science Center conducted a detailed investigation of the preservation status to identify the extent and types of corrosion. Using 3D stereoscopic measurement, they precisely recorded the shape of the artifact and analyzed its components non-destructively. As a result, they confirmed that bronze corrosion products had formed on the surface, with silicone oil-based oil and dust adhering on top. Contaminants were removed and the material reinforced using surfactants and ultrasonic scalers (which use microflows of ultrasonic vibrations to remove surface foreign substances).

Inscription on the sorghum jar (left) after preservation treatment

The Susuho, which underwent precise preservation treatment, revealed the inscription on its upper part clearly. The newly confirmed makers are An Hyeon, Igongjang, Kim Su-seong, and Chae Mu-jeok. Records in the Joseon Wangjo Sillok (Annals of the Joseon Dynasty), Gukjo Inmulgok, and Munwa Bangmok show that these individuals held the positions inscribed on the inscription at the time of the Jagyeokru’s production. A Cultural Heritage Administration official stated, “It is recorded that they played a very important role as astronomy experts in the making of the Jagyeokru.”

The Conservation Science Center also confirmed through 3D stereoscopic scanning and silicone replication that the faces and beards of the dragon patterns rising to the sky engraved on the left and right surfaces of the Susuho differ slightly. They also identified that the cloud patterns overlapping the dragon patterns were applied after attaching the dragon patterns to the Susuho surface. A Cultural Heritage Administration official said, “It is presumed that the Susuho was made by sequentially attaching intricately carved patterns. It is highly likely that the lost-wax casting method was used.”

Before and After Display of Large Guardian Silver Inlay

On the surface of the large Pasuho, the phrase indicating the production period of the Jagyeokru, ‘Gajeong Byeongsin Yukwol Iljo (嘉靖丙申六月 日造)’, was engraved vertically. Non-destructive component analysis detected a large amount of silver in the black inscription. Although it appeared black due to corrosion, the preservation treatment restored its original silver-white color. A Cultural Heritage Administration official explained, “It seems that the inscription was engraved on the surface of the large Pasuho using the silver inlay technique to mark the completion time of the Jagyeokru.”

This content was produced with the assistance of AI translation services.