The Cultural Heritage Administration to Unveil an Iryeongwongu (Spherical Sundial)

​The Cultural Heritage Administration (CHA; Administrator: Choi EungChon) will soon unveil the Iryeongwongu (Spherical Sundial) that was acquired at an auction in the United States this past March. The Iryeongwongu  will be presented to the press at the National Palace Museum of Korea (NPMK; Director: Kim In Kyu) on August 18 at 10 a.m and displayed to the public through a special exhibition held at the NPMK from August 19 through September 25.  

※ Iryeongwongu (Spherical Sundial) – Material: Bronze, Iron / Dimensions: 23.8 cm (height), 11.2 cm (diameter of the sphere) 

The Iryeongwongu (Spherical Sundial) is a rare relic that had not been known to academia. The circumstances in which the sundial had been removed from Korea are unknown, but the item was auctioned off by a private collector who had acquired it from the bereaved family of U.S. military officer who had been stationed in Japan.

The CHA and Overseas Korean Cultural Heritage Foundation (OKCHF; Secretary General: Kim Kae Sik) carried out detailed investigation and literature review on the Iryeongwongu upon first obtaining information on its auctioning late last year. They eventually succeeded with the repatriation after acquiring it at an auction held in the United States this past March.\ 

The Iryeongwongu, the first known Korean portable globular sundial, carries high historical and scientific value since its producer and production date can be confirmed through the featured inscription and seal. It also clearly demonstrates the succession and development of the science and technology of the Joseon Dynasty.

Sundials produced during the Joseon Dynasty are generally hemispherical (a type known as Angbuilgu in Korean). The gnomon* that allows telling the time through the shadow cast by the sun is affixed to a platform allowing the exact time to be measured only at a single location. However, the returned Iryeongwongu was made in the form of a sphere, demonstrating a marked difference from more conventional sundials. It was designed to allow the measurement of time in different regions by adjusting the body (comprised of two attached hemispheres) and a bar attached to the sphere. It is a precious heritage item demonstrating the achievements of the science and technology at the time.

* Gnomon: a sharp rod serving to cast a shadow

To measure time using the Iryeongwongu, it was leveled with a plumb line (Figs. 2, 3),* directed towards the north using a compass, and the latitude was set with the adjuster (Fig. 4). When the cast shadow falls into the groove, the current time appears in the sibochang (literally, time indicating window), a hole on the body.

* Plumb line: a piece of string with a weight attached to one end that is used to determine if something is perfectly horizontal or vertical. Currently, the plumb line of the sundial appears to be lost, but traces have been identified through CT scans.

One of the hemispheres is marked with ninety-six vertical lines and an inscription of the twelve animals of the zodiac as an indication of time. This is in accordance with the time system used during the late Joseon Dynasty that divided the day into twelve hours and ninety-six gak (one gak = fifteen minutes). Moreover, below the noon mark is a round hole known as a sibochang (Fig. 6). When the other hemisphere is moved in accordance with the movement of the sun, a tab appears through the hole indicating the time according to the system of the twelve zodiac animals.*

* The Iryeongwongu has a total of nine tabs that can appear in the sibochang hole. Among the twelve zodiac animals, time slots corresponding to the pig, rat, and ox do not appear. It is logical that the time slots for the pig (21:00–23:00), rat (23:00–1:00), and ox (1:00–3:00), the hours when there is no sun, were omitted since a sundial can only be used when the sun is out.

The Jagyeongnu (Clepsydra) of Changgyeonggung Palace and the Honcheonsigye (Armillary Clock), both of which have been designated as National Treasures, were also equipped with devices indicating time in accordance with the twelve animals of the zodiac system. Through this, it can be estimated that the Iryeongwongu (Spherical Sundial) succeeded the science and technology of the Joseon Dynasty but was newly designed for use outside of Korea (such as out at sea while sailing) in the face of increasing exchanges with foreign countries.

 In addition, the Iryeongwongu is a scientific device created using precision metal casting techniques and adorned with delicate silver sanggam inlay. * The base in the shape of flower with four petals is inlaid with designs of a dragon, a sailing ship, and the Chinese characters “日” (sun) and “月” (moon) (Fig. 7). It is expected to be utilized in the future for the study of various fields, including metalcrafts.

* Casting: a manufacturing process in which liquid metal is poured into a mold

* Sanggam: A technique involving the incision of varied designs onto surfaces such as metal and ceramics and filling in the carved space with materials such as gold or silver.

The repatriated item is also important since it is a scientific relic with a known producer and date of creation. On one of the hemispheres is an inscription reading “大朝鮮開國四百九十九年庚寅七月上澣新製” (meaning, “newly produced at the beginning of the seventh lunar month of the gyeongin year (twenty-seventh year in the sexagenary cycle) corresponding to the 499th year of the founding of the Joseon Dynasty”) together with a seal reading “尙稷鉉印” (seal of Sang Jikhyeon). This indicates that the sundial was produced by a person named Sang Jikhyeon (dates unknown) in the seventh month of 1890 (Fig. 9). According to The Annals of King Gojong (Gojong Sillok) and Daily Record of the Grand Secretariat (Seungjeongwon ilgi), Sang Jikhyeon was a military official who was active during the reign of King Gojong. He had been appointed to the positions of chongeoyeong,* byeoljang,** and byeolgunjik,*** and was responsible for escorting the king and defending the palace and capital.

* Chongeoyeong: Established during the reign of King Gojong, this is a garrison that was responsible for guarding the king and defending the palace and capital.

** Byeoljang: A military officer affiliated with a yeong (regiment) or cheong (administrative office) during the Joseon Dynasty

*** Byeolgukjik: A government post in charge of securing the safety of the king during the late Joseon Dynasty

Significant new data for the study of history and science are expected to be revealed through future investigations into the purpose of the lines and inscriptions incised on the body and the functional principles of the sundial.

The Iryeongwongu will be unveiled to the public at the National Palace Museum starting August 19 as part of the special exhibition Treasures of Ours, Treasured by Others: Journey of Korean Cultural Heritage (July 7–September 25, 2022). It will be displayed together with Borok (Case for Holding a Royal Seal) that was returned to Korea last month. The returned item is expected to be widely used in research and exhibitions at the museum.

The repatriation of the item was made possible through the CHA’s active administrative support and the OKCHF’s accumulated expertise, trained personnel, and close collaboration with professionals in the field. The CHA and OKCHF plan to continue their strenuous efforts at the active search, survey, and preemptive protection and utilization of important Korean cultural heritage objects held in overseas collections.

※ The acquisition of the item was carried out through the National Lottery Fund.

Attachment. Images

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Division: International Cooperation Division,

Heritage Promotion Bureau

Contact person: Kim Byeong Yun (042-481-4734), Lee Seon Hyeok (042-481-4735)