Remarkable 1,600-year-old Baekje wooden reservoir unearthed at Jangmi Fortress in Chungju

The National Jungwon Heritage Research Institute, under the Cultural Heritage Administration's National Institute of Cultural Heritage Research, held a public presentation Tuesday at Gungwongwan Hall and the Jangmi Fortress site in Chungju to share the results of its excavation. Researchers confirmed the largest wooden reservoir from Baekje's Hanseong period, a rammed-earth fortress wall, central-style pottery and a range of everyday artifacts — evidence that Baekje established and operated Chungju as a key strategic hub in the Jungwon region.

The excavation is part of a long-term research project jointly pursued by the Cultural Heritage Administration, North Chungcheong Province and Chungju City. Digging that began in the second half of 2022 has progressively uncovered, beneath an existing stone wall, a Baekje Hanseong-period earthen fortress, living spaces and a large wooden reservoir.

The most striking find is the wooden reservoir — the largest of its kind from the Baekje Hanseong period — discovered in the northern valley inside the fortress. Square in plan, it measures roughly 6.7 meters on each interior side and about 1.8 meters deep. Whole logs exceeding 7 meters in length were shaped and used for each wall face, then interlocked and stacked nine tiers high. Built in a valley where water naturally collected, the structure stored water and regulated its flow, demonstrating the systematic water-resource management and civil-engineering capabilities of Baekje some 1,600 years ago.

Beneath the current stone wall, researchers also found a Baekje Hanseong-period rammed-earth wall built by compacting layers of soil. The rammed-earth technique is a hallmark construction method of Baekje royal fortresses such as Pungnap Earthen Fortress and Mongchon Fortress, and was rarely seen at provincial mountain fortresses of the time. Its active application at Jangmi Fortress, along with large quantities of central-style Baekje Hanseong-period pottery and lacquerware, indicates that Baekje treated the site as a core hub in the Jungwon region and directly deployed the capital's technology and organizational capacity there.

Researchers are continuing a range of analyses to determine the structure and nature of the wooden reservoir. Soil from inside was water-screened to recover even minute artifacts and organic material. As a result, the team identified more than 50 species of cultivated and wild plants — including rice, adzuki beans and soybeans — along with bones from cattle, pigs, dogs and other animals. They also secured a wicker basket and an ox nose ring believed to be the earliest surviving examples of their kind found in Korea, as well as an axe with its handle fully intact, providing material that allows researchers to reconstruct the daily lives and surrounding environment of the people who lived at Jangmi Fortress in the fifth century.

These finds support the view that Jangmi Fortress was not simply a defensive mountain stronghold but a large-scale base that Baekje systematically managed at the state level.

A special exhibition of excavated artifacts opened Tuesday at the Gungwongwan Hall gallery and will run through Dec. 31. The excavation site will be open to the public on Thursday and Friday from 1:30 p.m. to 3:30 p.m., with two sessions in total. Applications for site visits can be submitted through the Jungwon Research Institute's website from 9 a.m. Tuesday through 5 p.m. Thursday, with 20 spots available per day on a first-come, first-served basis.

The National Jungwon Heritage Research Institute plans to continue interdisciplinary research and natural-science analysis of the wooden reservoir and other excavation findings, and to expand its investigation of the interior spaces of Jangmi Fortress. Through this work, it aims to build a clearer picture of how Baekje established and operated its Jungwon regional hub, and will continue to share results with the public.