In the western area of Liaoning, China, Xianbei established Former Yan, Later Yan, and Northern Yan around the 4th and 5th centuries. These three countries are often referred to as Sanyan (the three Yan countries). The period of Sanyan was the Kofun (Tumulus) period in Japan, which suggests that the Sanyan culture had a significant influence on the Kofun culture, especially in terms of arms and armor. Therefore, survey and research on excavated artifacts and remains of ancient palaces in the Sanyan period, as well as preservation and restoration of those cultural relics are very important not only for Liaoning Province in China, but also for Japan in studying the primitive and ancient history of Japan.
China faces serious issues regarding the establishment of preservation policies for cultural relics. The Institute of Cultural Relics and Archaeology of Liaoning Province have a strong interest in advanced techniques and cases of preservation of remains in other countries in relation to scientific methods for the conservation of excavated artifacts and preservation policies for large-scale remains. Meanwhile, the NNRICP has accumulated research results and techniques for research on excavated artifacts utilizing scientific and conservation methods. The NNRICP also has experience with both in large-scale remains such as the Heijo Palace Site. The interest shown by the Liaoning Provincial Institute of Cultural Relics and Archaeological Research and research activities by the NNRICP matched perfectly, a match that promotes research on cultural relics and remains in Liaoning Province, China, and their conservation and preservation have proceeded under mutual and close cooperation between the two countries in the form of international joint research.

In 1996, The NNRICP and the Institute of Cultural Relics and Archaeology of Liaoning Province concluded an Agreement on Joint Research on the Preservation of Ancient Palace Remains in East Asia – Conservation Research on Ironware and Other Metalware Excavated from Palace Remains in Sanyan, and initiated joint research. This research continued to shift toward a Comparative Study on Antiquities Excavated from Ancient Remains between the 3rd and 6th Centuries in China and Japan, and to the Investigation and Maintenance of Sui and Tang graves in the Chaoyang District. This study is currently being conducted under Research on Culture at Ancient Palaces in Liaoxi Region of the Dong (Eastern) Jin Dynasty and Sixteen Kingdoms Period, which is scheduled to continue until FY 2015. Research by the NNRICP and the Institute of Cultural Relics and Archaeology of Liaoning Province is conducted in cooperation with the Agency of Cultural Affairs of Liaoning Province, Liaoning Provincial Museum, and Department of Culture and Sports of Shuangta District, Chaoyang city.
The NNRICP was in charge of providing guidance on basic skills and technical training for conservation, and organizing interactions regarding measurement and photography techniques for antiquities at the NNRICP and the Institute of Cultural Relics and Archaeology of Liaoning Province. The NNRICP conducted element analysis utilizing a portable X-ray fluorescence analyzer, and measured antiquities utilizing a small 3D measurement device at the Institute of Cultural Relics and Archaeology of Liaoning Province. Since there were some differences in photographic techniques and measurement methods between Japan and China, such interactions were of great benefit for both countries in understanding different methods and techniques for further cooperation.

The 18-year joint research between the NNRICP and the Institute of Cultural Relics and Archaeology of Liaoning Province has resulted in the publication of several studies such as Selection of Sanyan's Cultural Relics, East Asia Archaeological Studies – A Collection of Joint Research by China and Japan, and the Investigation and Maintenance of Sui and Tang graves in the Chaoyang District. In October 2009, the NNRICP Asuka Historical Museum held an exhibition entitled The Glory of the Northern Equestrian People – Archaeological Discovery in Sanyan Culture. This exhibition introduced Sanyan's cultural relics excavated from Lamadong burial mound, which had been jointly investigated by the two institutions, and excavated artifacts in Japan that were influenced by the cultural relics. In addition, this exhibition was also held as a pre-event for the 1300th anniversary of the Nara Heijo-Kyo capital, and brought the celebration to life.
The currently ongoing joint research is scheduled to end in 2015, and an international symposium and other events are also scheduled on the same year. Plans for the following FY 2016 have not yet been determined, and it is necessary to establish future directions considering the further promotion of academic interactions between both countries.