The accession ceremony of the Zidanku Silk Manuscripts (Volumes II and III) is held at the Hunan Museum in Changsha, capital of central China's Hunan Province, Oct. 13, 2025. (Xinhua/Chen Zhenhai)

CHANGSHA, Oct. 13 (Xinhua) -- Silk manuscripts dating back about 2,300 years have been returned to China, 79 years after they were smuggled out of the country, with their return resulting from cooperation between Chinese and U.S. cultural institutions.

The second and third volumes of the Zidanku Silk Manuscripts, precious cultural artifacts dating back to the Warring States Period (475-221 B.C.), were on Monday officially repatriated to Hunan Province in central China. They will be permanently archived in the Hunan Museum in Changsha, the provincial capital.

These manuscripts, which were taken from a Chu-state tomb by tomb raiders at the Zidanku site in Changsha in 1942, consist of three volumes: "Sishi Ling," "Wuxing Ling" and "Gongshou Zhan." They are a systematic record of astronomy, calendars, cosmology and military divination from China's pre-Qin period. The silk manuscripts are the earliest examples of silk text discovered to date and form the oldest classical Chinese book in the true sense. They were smuggled out of China in 1946.

At the accession ceremony of the Zidanku Silk Manuscripts (Volumes II and III) on Monday, National Cultural Heritage Administration (NCHA) head Rao Quan said the return of the manuscripts is a significant achievement stemming from years of Sino-U.S. cultural and museum cooperation, and an example for international cooperation endeavors regarding artifact restitution.

Rao said the Zidanku Silk Manuscripts serve as invaluable physical artifacts for the study of philology, bibliography, intellectual history and the history of calligraphy. They provide key documentary evidence for research into early Chinese civilization and cultural forms.

Chase Robinson, director of the Smithsonian's National Museum of Asian Art in the United States, said the transfer of these artifacts follows several months of thoughtful discussion. It also continues the century-long partnership between the museum and Chinese cultural institutions

Through Sino-U.S. cooperation concerning the return of cultural property, the "Wuxing Ling" and "Gongshou Zhan" volumes were returned to China by the Smithsonian's National Museum of Asian Art this year, arriving in Beijing on May 18.

Duan Xiaoming, curator of the Hunan Museum, said the return of the silk manuscripts will enable the Hunan Museum to integrate the returned volumes with its existing collection -- which includes the only original fragment of the Zidanku manuscripts, as well as a large number of other Chu-state cultural relics.

"This will help us build a more systematic and in-depth research, interpretation and exhibition framework for Chu-state culture," he said.

The owner of the tomb at the Zidanku site in Changsha is believed to have been a noble of the late Warring States period from the State of Chu. Other artifacts, including silk fabrics, pottery and jade objects were also found in the tomb. The only remaining fragment of the Zidanku manuscripts in China is housed at the Hunan Museum. The fragment measures 4.6 cm in length and 2.7 cm in width. It contains three lines of red boundary marks, with 17 visible black characters, 14 of which are legible.

Yu Yanjiao, a researcher at the Hunan Museum, said the returned manuscripts consist of 132 pieces or sets and the contents include auspicious and inauspicious dates in four seasons and 12 months of a year, as well as directions, dates and hours for attacking and defending cities.

The returned manuscripts underwent 14 days of environmental adaptation observation after their arrival at the Hunan Museum on Sept. 10. Following a non-destructive evaluation, they are now stored in a temperature-controlled and humidity-controlled environment. A team of experts is scientifically researching a microbial disinfection plan and conducting simulation experiments to ensure that the sterilization process does not damage the material or ink of these manuscripts.

Hunan Museum has also completed standardized imaging of all the silk manuscripts, discovering over 40 previously imperceptible ink characters on one piece of silk that had not fully separated.

Hunan Museum will conduct in-depth non-destructive testing, using techniques like hyperspectral imaging and X-ray fluorescence surface scanning to carry out scientific restoration and comprehensive digital archiving of the silk manuscripts to ensure full and sustainable protection of these relics.

At the same time, via an improved collaboration mechanism, the museum will ensure that American scholars can receive timely updates on research progress, thus enabling them to explore paths of relic preservation and study.

Additionally, Hunan Museum plans to curate a special exhibition, using digital technology, to present the intricate details of the silk manuscripts, the interpretation of the texts and their content, allowing visitors to gain a more direct and profound understanding.

Rao said that China will continue to work with U.S. cultural and academic communities, deepening joint research, increasing cultural exchanges and enriching academic outcomes. ■

Staff members prepare to conduct standardized image collection of the Zidanku Silk Manuscripts at the Hunan Museum in Changsha, capital of central China's Hunan Province, Sept. 11, 2025. Two volumes of Chinese silk manuscripts dating back about 2,300 years have been returned to central China, 79 years after they were smuggled out of the country, through cooperation between Chinese and the U.S. cultural institutions. (Xinhua/Xue Yuge)

This photo taken on Sept. 11, 2025 shows parts of the Zidanku Silk Manuscripts at the Hunan Museum in Changsha, capital of central China's Hunan Province. Two volumes of Chinese silk manuscripts dating back about 2,300 years have been returned to central China, 79 years after they were smuggled out of the country, through cooperation between Chinese and the U.S. cultural institutions. (Xinhua/Xue Yuge)

This photo taken on Sept. 11, 2025 shows parts of the Zidanku Silk Manuscripts at the Hunan Museum in Changsha, capital of central China's Hunan Province. Two volumes of Chinese silk manuscripts dating back about 2,300 years have been returned to central China, 79 years after they were smuggled out of the country, through cooperation between Chinese and the U.S. cultural institutions. (Xinhua/Xue Yuge)

This photo taken on Sept. 11, 2025 shows parts of the Zidanku Silk Manuscripts at the Hunan Museum in Changsha, capital of central China's Hunan Province. Two volumes of Chinese silk manuscripts dating back about 2,300 years have been returned to central China, 79 years after they were smuggled out of the country, through cooperation between Chinese and the U.S. cultural institutions. (Xinhua/Xue Yuge)

Staff members transfer a box containing the Zidanku Silk Manuscripts at Changsha South Railway Station in Changsha, capital of central China's Hunan Province, Sept. 10, 2025. Two volumes of Chinese silk manuscripts dating back about 2,300 years have been returned to central China, 79 years after they were smuggled out of the country, through cooperation between Chinese and the U.S. cultural institutions. (Xinhua/Xue Yuge)

Experts verify the Zidanku Silk Manuscripts at the Hunan Museum in Changsha, capital of central China's Hunan Province, Sept. 11, 2025. Two volumes of Chinese silk manuscripts dating back about 2,300 years have been returned to central China, 79 years after they were smuggled out of the country, through cooperation between Chinese and the U.S. cultural institutions. (Xinhua/Xue Yuge)

Staff members open the boxes containing the Zidanku Silk Manuscripts at the Hunan Museum in Changsha, capital of central China's Hunan Province, Sept. 11, 2025. Two volumes of Chinese silk manuscripts dating back about 2,300 years have been returned to central China, 79 years after they were smuggled out of the country, through cooperation between Chinese and the U.S. cultural institutions. (Xinhua/Xue Yuge)

This photo taken on Sept. 11, 2025 shows parts of the Zidanku Silk Manuscripts at the Hunan Museum in Changsha, capital of central China's Hunan Province. Two volumes of Chinese silk manuscripts dating back about 2,300 years have been returned to central China, 79 years after they were smuggled out of the country, through cooperation between Chinese and the U.S. cultural institutions. (Xinhua/Xue Yuge)

This photo taken on Sept. 11, 2025 shows parts of the Zidanku Silk Manuscripts at the Hunan Museum in Changsha, capital of central China's Hunan Province. Two volumes of Chinese silk manuscripts dating back about 2,300 years have been returned to central China, 79 years after they were smuggled out of the country, through cooperation between Chinese and the U.S. cultural institutions. (Xinhua/Xue Yuge)

The accession ceremony of the Zidanku Silk Manuscripts (Volumes II and III) is held at the Hunan Museum in Changsha, capital of central China's Hunan Province, Oct. 13, 2025. Two volumes of Chinese silk manuscripts dating back about 2,300 years have been returned to central China, 79 years after they were smuggled out of the country, through cooperation between Chinese and the U.S. cultural institutions. (Xinhua/Chen Zhenhai)

This photo taken on Oct. 13, 2025 shows part of the Zidanku Silk Manuscripts on display at the Hunan Museum in Changsha, capital of central China's Hunan Province. Two volumes of Chinese silk manuscripts dating back about 2,300 years have been returned to central China, 79 years after they were smuggled out of the country, through cooperation between Chinese and the U.S. cultural institutions. (Xinhua/Chen Zhenhai)

Journalists take images of the Zidanku Silk Manuscripts on display at the Hunan Museum in Changsha, capital of central China's Hunan Province, Oct. 13, 2025. Two volumes of Chinese silk manuscripts dating back about 2,300 years have been returned to central China, 79 years after they were smuggled out of the country, through cooperation between Chinese and the U.S. cultural institutions. (Xinhua/Chen Zhenhai)

This photo taken on Oct. 13, 2025 shows part of the Zidanku Silk Manuscripts on display at the Hunan Museum in Changsha, capital of central China's Hunan Province. Two volumes of Chinese silk manuscripts dating back about 2,300 years have been returned to central China, 79 years after they were smuggled out of the country, through cooperation between Chinese and the U.S. cultural institutions. (Xinhua/Chen Zhenhai)

This photo taken on Oct. 13, 2025 shows part of the Zidanku Silk Manuscripts on display at the Hunan Museum in Changsha, capital of central China's Hunan Province. Two volumes of Chinese silk manuscripts dating back about 2,300 years have been returned to central China, 79 years after they were smuggled out of the country, through cooperation between Chinese and the U.S. cultural institutions. (Xinhua/Chen Zhenhai)