National Research Institute of Cultural Heritage

The division actively conducts scientific analysis of various materials such as metal, pottery, pigment, stone, bone, organic residues and many others. Using state-of-the-art technology, the division analyzes the chemical composition and crystalline structure of metal, stone, glass, ceramics, and pigments to reveal the applied production technologies, provenance, and preservation state of heritage. The division also studies the genetic information, diet, disease history, and environment of the people and animals of the past using DNA and stable isotope analysis. Furthermore, organic materials such as paper, textiles, natural resins, adhesives, and organic residues in soil and pottery can also provide insight into ancient cultures.

The Conservation Science Division is charting a new chapter in chronology by establishing infrastructure and facilities for dating archaeological materials. Firstly, radiocarbon dating can measure the age of organic materials (i.e., bones, wood, paper, textiles, etc.) using an AMS (accelerator mass spectrometer). In addition, the introduction of OSL (optically stimulated luminescence) dating system allows the dating of inorganic materials such as pottery, roof tiles, soil layers, and more. The division plans to systematically study and manage the entire dating cycle from sampling and pretreatment to scientific dating, sample storage, and database management.

Scientific investigations conducted prior to the deliberation of national designation of cultural heritage improves the understanding of the materials, their restoration status, preservation status, and more. It is being incorporated into policies for managing cultural heritage such as securing data for the designation and verification of cultural heritage and determining whether or not conservation treatment is necessary following designation. In addition, scientific surveys are conducted as part of the periodic survey of national cultural heritage such as national treasures or treasures, along with details on materials and preservation states. Various non-destructive analyses contribute to the systematic preservation and management of nationally-designated cultural heritage by providing fundamental data.

The weight and size of large Buddhist paintings has made it difficult for them to be moved and studied in depth. The division has been conducting a project on the scientific examination of large Buddhist paintings since 2015 in order to establish long-term preservation methods and acquire basic information. These activities include producing damage drawings by examining the damage or repair status of the painting, infrared irradiation to check drafts, and analysis of coloring materials (pigments, dyes, fabrics, etc.). Analysis on the conservation status and production techniques of large Buddhist paintings is used as important data for conservation and management and related research.

In order to preserve stone cultural heritage, it is necessary to understand its material composition, the cause and process of any deterioration, and its characteristics. Nondestructive examination is required to determine the type of deterioration taking place and the risks associated with it. Nondestructive diagnosis techniques include deterioration mapping, ultrasonic testing, infrared thermography analysis, and hyper-spectral image analysis. Stone cultural heritage surface changes can be quantified using these methods, which are highly effective and efficient.

The division is currently working to establish a long-term storage system that promotes sample management across the entire process from collection, utilization, disclosure, and sharing to disposal. Samples will be sorted by material, including earthenware, metal, stone, human remains, and organic residues. Additionally, the division establishes a scientific database on cultural heritage that is systematically and comprehensively managed and utilized.