Research on Asuka-daibutsu using a portable X-ray diffraction device
In Asuka-dera Temple located in Asuka village, Nara prefecture, the statue of Shaka Nyorai (the so called “Asuka-daibutsu”), which is about three meters in height, is enshrined as the principal image of the temple. According to historical sources, the statue is considered to have been made by Tori Busshi in 606. It is an important statue because it is considered to be the first Joroku Buddha in Japan. However, there are various opinions as to which part of the statue was originally made by Tori Busshi because it was damaged by fire in the early Kamakura period.
After the opening time of Asuka-dera Temple on June 16th and 17th in 2016, research on the preserved state and production techniques of Asuka-daibutsu was conducted by experts in art history, conservation science, restoration and three-dimensional measurement. This research was managed as a part of the “Japan-South Korea Joint Research on Bronze Buddhist Statues of East Asia from the 5th through the 9th Century” (the research representative is Prof. Fujioka of Osaka University.). From the National Research Institute for Cultural Properties, Tokyo (NRICPT), Yasuhiro HAYAKAWA, Masahide INUZUKA and Mai SARAI participated in this research and conducted the investigation of materials on the surface of the statue by using a portable X-ray diffraction device (RIKEN KEIKI Co., Ltd., XRDF), which was introduced to NRICPT in the last fiscal year.
Scaffolding was constructed around the statue, and then we carried out the measurement on the surface of the head and body of the statue (the number of measured points was 10). Together with the 3 measured points on a fragment considered to have been a part of Asuka-daibutsu, the number of measured points was 13 in total during this research period.
The crystal structure of materials can be obtained by the portable X-ray diffraction device. The chemical compounds can be identified from the information about the crystal structure by combining the information about the elements constituting materials obtained by X-ray fluorescent analysis conducted by Osaka University and the National Museum of Korea. In this research, copper compounds existing on the surface of the statue can be identified and the comparison of chemical compounds on different measurement points will be possible.
We are now analyzing these data in more detail, and plan to report the results of the analysis within this fiscal year.