| ■Tokyo National Research
Institute for Cultural Properties |
■Center for Conservation
Science |
| ■Department of Art Research,
Archives and Information Systems |
■Japan Center for
International Cooperation in Conservation |
| ■Department of Intangible
Cultural Heritage |
|
Applying agricultural sheets to prevent weed growth as part of cultivating kōzo.
Mr. Fukunishi explaining about kōzo raw material.
Although a wide range of tools and raw materials are used in the preservation and restoration of cultural property, fine arts, and crafts, many are at risk of being discontinued in the future due to a lack of skilled successors and increasing difficulty in securing the necessary materials. In response to this situation, the Center for Conservation Science, Department of Intangible Cultural Heritage, and the Department of Art Research, Archives and Information Systems at the Tokyo National Research Institute for Cultural Properties (TOBUNKEN) has been involved in the commissioned research of “Investigation of Tools and Materials Used for the Preservation and Restoration of Fine Arts and Crafts” as part of the project of the Agency for Cultural Affairs, “Support for the Management of Tools and Materials Used for the Preservation and Restoration of Fine Arts and Crafts.” This report introduces a field survey of the cultivation of kozo (paper mulberry), the raw material for washi (Japanese paper), which is essential for the restoration of cultural property. It also presents the current use of wood ash in the cooking process used to obtain kozo fibers.
We visited four kozo fields in Yoshino Town and Gojo City, Nara Prefecture, on June 9-10, 2025, and learned about the meticulous work involved in tasks called mekaki (the removal of unnecessary new shoots and buds to concentrate nutrients on the remaining ones) and weed control, as well as the various innovations and challenges involved in the cultivation process. There is no end to the challenges, such as determining the cause of “red streaks” that appear on the inner bark, which reduce the usable amount of raw material because they discolor the fibers, and dealing with insects that were not seen in the past. The number of people responsible for this type of cultivation management is decreasing year by year, which poses a significant challenge in terms of ensuring a stable supply of this raw material.
We also visited the paper-making factories of Mr. FUKUNISHI Masayuki and Mr. UEKUBO Ryoji. The raw materials and wood ash are carefully selected and the delicate process of removing inclusions one-by-one by hand is repeated, because such inclusions make the material unsuitable for the restoration of cultural property. The issue of ensuring a stable supply of wood ash in the future was also discussed. An alkaline solution obtained from wood ash is essential for extracting kozo fibers, but it is also becoming increasingly difficult to procure the ash to obtain good quality fiber.
Going forward, we will conduct scientific research into the interactions between ash derived from various plant species and various raw materials and woods, with the aim of addressing specific challenges. In parallel, we will focus on strengthening our role as a network hub, connecting experts and knowledge across related fields, while continuing our ongoing efforts to document production techniques and processes.
Visual investigation of damage made by termites that intruded through cracks in the floor and observation of living termites
Observation of lacquered door panels with pest damage and confirmation of sampling points
Visual investigation of decorations made by colored lacquer maki-e technique
Wat Ratchapradit, located in Bangkok, Thailand, is a first-grade Royal temple founded by King Rama IV in 1864. Since the temple’s foundation, the double-door openings of the windows and entrances of the ordination hall have been adorned with many lacquered panels made in Japan. Mother-of-pearl inlay with underpainting and colored lacquer maki-e were used to apply motifs such as flowers and birds, as well as Chinese legends, on these panels, which are highly decorative. Over time, deterioration has been detected on the panels, and therefore the Fine Arts Department of the Ministry of Culture of Thailand has been restoring them. TOBUNKEN has provided technical assistance for the restoration and conducted studies on the panels.
To maintain the solemn atmosphere of the ordination hall as a place of worship, the lacquered door panels will be returned to their original positions. However, some panels were damaged, presumably by insects. The same problems may recur if the panels are returned to their original positions without protective measures. For that reason, a research project for on-site conservation of the lacquered door panels was launched as a funded study by Wat Ratchapradit, and we conducted an on-site investigation on June 9-11, 2025.
We observed the general condition of the ordination hall, as well as the presence of wood-boring pests such as termites. We also visually inspected the lacquered door panels that were damaged by insects. Initially, we thought the panels had not been damaged recently and that insect activity had ceased. However, through our investigation, we discovered that termites currently enter the ordination hall through small cracks in the floor and that the panels may still be further damaged by termites. We will propose protective measures to the Thai side to maintain the condition of the lacquered door panels in their original positions.
In addition, we examined the lacquered door panels. Some uncertainties remain regarding the materials and techniques used for the panels, and therefore we are conducting visual investigations and scientific analyses of the fragmented materials. Based on the results of the study, we will make suggestions for the restoration and replication of the lacquered door panels.
Conference venue
Presentation scene (poster session）
Presentation scene (oral session）
From May 6 to May 9, 2025, three members of the Center for Conservation Science―Dr. AKIYAMA Junko (Head of Preventive Conservation Section), Dr. Chi Chih Lien (Associate Fellow, Analytical Science Section), and Ms. TERASHIMA Kai (Research Assistant, Analytical Science Section)—participated in the International Conference on Analytical Techniques for Heritage Studies and Conservation – TECHNART 2025, held in Perugia, Italy.
TECHNART is an international conference focused on scientific approaches to the analysis of cultural heritage. The 2025 program featured the latest developments in non-invasive, imaging-based analytical techniques such as Macro X-ray Fluorescence Scanning (MA-XRF), Macro X-ray Powder Diffraction Scanning (MA-XRPD), and Reflectance Imaging Spectroscopy (RIS), as well as studies on image analysis using machine learning and the development of environmentally sustainable conservation materials. (See: TECHNART 2025 program.pdf)
Dr. Chi presented a poster entitled “Analysis of Green Coloring Materials in the Takamatsu Matsudaira Family Illustrated Book on Natural History Using Hyperspectral Imaging.” Focusing on a designated tangible cultural property of Kagawa Prefecture, the study employed hyperspectral reflectance data and principal component analysis (PCA) to classify and identify the green colorants used. This approach, which integrates large-scale spectral datasets with statistical methods, proved effective for gaining insight into painting materials and techniques. Discussions and exchanges during the session further underscored the importance of developing comprehensive pigment databases and advancing multidimensional data analysis as shared international challenges.
Ms. TERASHIMA gave an oral presentation titled “Investigation on the Use of Smalt in 17th–18th-Century Japanese Illustrations Using MA-XRF and RIS-VNIR,” focusing on two-dimensional spectroscopic analysis of Edo-period paintings. This presentation highlighted the use of smalt (blue pigments made from cobalt-containing glass), commonly seen in Western oil paintings, in Japanese artworks, and discussed its unique application and coloring effects. Presentations by participants from the United States and Portugal on similar topics reflected international interest, providing valuable opportunities for comparative perspectives and deeper discussions.
Many of the international research teams included not only experts in conservation science and cultural heritage science but also developers of hardware and software for analytical instruments, demonstrating an interdisciplinary approach. While cross-disciplinary research is advancing in Japan as well, further expansion of venues for diverse presentations will be key to future development. Insights gained through participation in this conference will be integrated into ongoing and future research activities.
Inspection of a funori harvesting site
Consultation with Kamitsushima Fishery Cooperative
The Center for Conservation Science of Tokyo National Research Institute for Cultural Properties (TOBUNKEN) has been commissioned by the Agency for Cultural Affairs to conduct research on “Tools and Raw Materials Used in Fine Arts and Crafts.” We are carrying out this project in collaboration with the Department of Art Research, Archives and Information Systems and the Department of Intangible Cultural Heritage. In this regard, on May 13-14, 2025, we visited Tsushima City, Nagasaki Prefecture, to conduct a survey on a material called “funori.”
Funori is a collective term for species of seaweeds belonging to the Genus Gloiopeltis in the Family Endocladiaceae, with ma-funori (Gloiopeltis tenax) and fukuro-funori (Gloiopeltis furucata) being the primary varieties used in a variety of applications. Funori is often bleached, sun-dried, and processed into a sheet-like form known as “ita-funori.” Paste made by cooking funori in water is widely used in the production of arts and crafts (such as textiles, plaster, brushes, and so on) and in cultural property restoration. In particular, its solubility in water makes it highly valued in restoration works, as it can easily be removed with water. Based on this characteristic, funori is used for temporary surface coating to protect artworks during restoration. Conservators also consider it to have a cleaning effect, making it an indispensable material for cultural property restoration.
However, due to a shortage of workers and changes in the environment, it has become increasingly difficult to obtain funori.
Most of the funori used as adhesive is harvested in Tsushima and the Goto Islands. For this survey, we visited Kamitsushima and Mitsushima, which have fishermen’s cooperatives, accompanied by Mr. OKAMURA Kazuyuki of the Agency for Cultural Affairs and Mr. OWAKI Toyohiro of Owaki Manzo Shoten Co., Ltd., a valuable manufacturer in the production of dried funori, along with representatives from the Nagasaki Prefecture of Fisheries Co-operative Association. We held a lecture meeting with seaweed harvesters about the uses and importance of funori, with lectures about the methods of funori cultivation by Ms. SAITSU Mako of the Tsushima Fisheries Industry Extension and Guidance Center, Tsushima Development Bureau, Nagasaki Prefecture, and representatives from TOBUNKEN, followed by a meeting to discuss stable supply. The participants expressed great interest in the efforts to increase production mentioned by Ms. SAITSU, making it a very valuable opportunity for discussion. We also inspected the local harvesting sites and observed the growth conditions of funori.
In the current situation in which the procurement of tools and raw materials is becoming difficult, this was a valuable opportunity to once again recognize the importance of collaboration and cooperation among various organizations to move forward together.
Certificate of Appreciation for the donation
The Japan Aviation Association (JAA) has donated 19,517 volumes of scientific journals and other materials collected by Mr. YAMAZAKI Yoshio to the Tokyo National Research Institute for Cultural Properties (TOBUNKEN).
Mr. YAMAZAKI (1903-1981) joined the Aeronautical Research Institute of Tokyo Imperial University before World War II, and was later involved in glider design, production, promotion, and engineering while working as a sports official at the Ministry of Education. Mr. YAMAZAKI collected a wide range of materials related to aircraft development, including documents, drawings, photographs, and materials for model airplanes, as well as scientific magazines (including aviation magazines) mainly from the Taisho and early Showa periods. These scientific journals are in good condition and are valuable documents for research and study of the history of modern heritage.
TOBUNKEN has been conducting joint research with JAA since 2007, and hopes to utilize these materials for future historical research on science and technology. These documents can be searched using the general search function on the TOBUNKEN website (https://www.tobunken.go.jp/archives/?lang=en). The original materials can be viewed in the TOBUNKEN library. Please feel free to use them.
In FY2024, the Conservation Science Center newly installed a Raman spectrometer, a 3D fluorescence spectrophotometer, and a high-performance liquid chromatography system, and updated the existing pyrolysis GC/MS and ion chromatograph. These instruments are introduced below. (Figure 1)
Raman spectrometer
When a material is irradiated with laser light, the wavelength of Raman scattered light changes depending on the molecular structure of the material at the point of irradiation. Using this principle, it is possible to analyze the structure of a sample in a non-contact and non-destructive manner. For this purpose, we have introduced three types of instruments: a stationary Raman microspectroscope that can also be used for mapping, a portable Raman microspectroscope that can be carried around, and a hand-held Raman spectroscope that is compact and easy to carry around. Raman spectroscopy can be used to analyze any sample other than pure metals, whether inorganic or organic. It can be used for various applications such as identification of dyes and pigments, elucidation of the causes of corrosion, and analysis of adhering materials on cultural properties. (Figure 2)
Three-dimensional spectrofluorometer
Since the wavelength and intensity of fluorescence emitted from a sample varies depending on its structure, fluorescence analysis can be used to estimate the structure of materials constituting cultural properties. It is a non-contact, non-destructive measurement method and can be used to analyze any sample that emits fluorescence. There are a surprisingly large number of samples that emit fluorescence (for example, fluorescence can be detected in cloth, paper, and wood in many cases), and many cultural properties can be analyzed using this method, but it is a particularly powerful analysis tool for dyes. (Figure 3)
High-performance liquid chromatography system
Used for the determination of aldehydes in the air and dyes in textiles, this system is equipped with a PDA detector, which is more powerful than a typical UV detector for identifying unknown substances. Since extraction is required, this is basically a destructive analysis method.
Pyrolysis GC/MS (updated)
This instrument is capable of analyzing in detail the structure of samples consisting of polymers, such as paper, fabric, lacquer, and wood. Although it is a destructive method, it is possible to analyze even a very small amount of sample (1 mg). Qualitative quantification of atmospheric odors and residual solvents is also possible.
Ion chromatograph (updated)
This is used for the quantitative determination of ammonia and organic acids in the air, and chloride and nitrate ions in water. It employs a suppressor method and is extremely sensitive.
We will continue to analyze cultural properties using these instruments.
Fig.1: Photographs of newly introduced/updated instruments
A：Raman spectrometer (stationary type micro Raman spectrometer)B：Three-dimensional spectrofluorometerC：High-performance liquid chromatography systemD：Pyrolysis GC/MSE：Ion chromatograph
Fig.2: Analysis of various colorants by Raman spectrometry
It can be seen that the spectra obtained are different depending on the material colorant. A resolution of 1 µm enables identification of the colorant material. In particular, the ability to analyze inksticks nondestructively is a major feature. In addition to pigments, a wide variety of samples can be analyzed, including dyes, minerals, metal corrosion, and fibers.
Fig.3: Three-dimensional spectrofluorescence spectra of cloth dyed with natural dyes before and after accelerated aging test
A: Before accelerated aging test B: After accelerated aging test
Accelerated aging test causes an overall decrease in fluorescence intensity. In particular, there are marked decreases in fluorescence intensity around the excitation wavelength of 280 nm and fluorescence wavelength of 420 nm. Since the fluorescence pattern changes depending on the degree of deterioration and the material itself, it is useful for evaluating the degree of deterioration and for analyzing the differences between different materials.
The general discussion
Research introduction by organizations related to Museum IPM
On February 21, 2025, the Center for Conservation Science (CCS) hosted a forum titled “Considering the Conservation of the Museum Collections After the Suspension of Major Fumigation Gas Sales.” This event was co-hosted by the Agency for Cultural Affairs, the Japan Society for the Conservation of Cultural Properties, and the Japan Society for Scientific Studies on Cultural Properties.
In cases of extensive insect and mold damage, gas fumigation is used to mitigate the damage. Alternatively, gas fumigation may be utilized to prevent insects and molds from infesting incoming collections. This method has also been applied to museum collections that have suffered fungal damage due to disasters. Gas fumigation is a crucial technology for preventing biological deterioration in the conservation of museum collections in Japan. However, the sale of one of the primary fumigation gases was scheduled to cease at the end of March 2025. This decision stems from the growing awareness of the negative impact of fumigation gases on human health and the global environment.
At the forum, experts and organizations in this field were invited to discuss alternative methods for conserving museum collections without the use of gas fumigation, in response to the contemporary societal demand for sustainable practices.
In the keynote speeches, Mr. YONEMURA Sachio (Agency for Cultural Affairs) and Ms. KIGAWA Rika (Kyushu National Museum) spoke about the future of conservation in museum collections, focusing on Integrated Pest Management in museums (Museum IPM). Additionally, during the lunch break, Mr. WATANABE Hiroki (Kyushu National Museum) and Mr. SHIMADA Megumi (Tokyo National Research Institute for Cultural Properties) reported on international research topics related to Museum IPM. This was followed by lectures from Mr. HIDAKA Shingo (National Museum of Ethnology), Mr. IWATA Yasuyuki (Japan Institute of Insect and Fungal Damage to Cultural Properties), and Mr. MABUCHI Hajime (The National Center for the Promotion of Cultural Properties) on the practical applications of Museum IPM, the qualifications associated with it, and the theory and practice of mold control.
The general discussion was moderated by Mr. TATEISHI Toru (The Museum of the Imperial Collections, Sannomaru Shozokan. Each speaker, including Mr. KODANI Ryusuke (Cultural Heritage Disaster Risk Management Center), Mr. WADA Hiroshi (Tokyo National Museum), Ms. FURIHATA Junko (Kyoto National Museum), Mr. WAKIYA Soichiro (Nara National Research Institute for Cultural Properties), and Mr. TAKAHATA Makoto (Imperial Household Agency) took to the stage to discuss methods for conserving museum collections without relying on gas fumigation.
The venues were the seminar room and conference room (satellite venue) on the basement floor, and in the foyer, organizations related to Museum IPM showcased booths highlighting their recent research. Approximately 170 individuals attended in person, while around 750 accounts were registered for a simultaneous online broadcast, resulting in a substantial audience. The CCS hopes that this forum provided an opportunity to foster more dynamic discussions and enable those concerned to take meaningful steps toward addressing these issues.
The 60th Autumn Conference of the Korean Society for Conservation Science for Cultural Heritage
A presentation by a participant
A delegation from the Tokyo National Research Institute for Cultural Properties (TOBUNKEN) participated in the 60th Autumn Conference of the Korean Society for Conservation Science for Cultural Heritage, held on November 8-9, 2024, at the International Convention Center of Jeonbuk National University in Jeonju, Korea.
At this year’s conference, a joint presentation was made by representatives from Japan and Korea in a special session, “Disaster Prevention and Preventive Conservation of Cultural Heritage Against Climate Change.” In the session, presentations by representatives from Japan by Mr. KOZUMA Yosei, Director of Cultural Heritage Disaster Risk Management Center, TATEISHI Toru, the Museum of the Imperial Collections, Sannomaru Shozokan, and Ms. HAGA Ayae, Researcher of the Center for Conservation Science. In addition, in the poster session, Mr. CHIBA Tsuyoshi, Researcher of the Center for Conservation Science, reported on the preservation of aviation materials in Japan, comparing it with designated cultural properties in Korea and discussing the challenges of the Japanese system.
In this special session, after a discussion on how the country and the administration should respond to rescue cultural properties in the event of a disaster, reports were made on changes in the damage situation, for example damage caused by termite species, in response to actual temperature increases in individual regions. The Japanese representatives reported on the preservation of materials damaged in the Great East Japan Earthquake, and on an investigation into volatile components that can emanate from cultural properties resulting from the damage to the materials, and the impact on the materials.
Responding to disasters does not only involve predicting and preventing damage, but also sharing information on a wider range of countermeasures and broadening knowledge, which will enable flexible responses and create a system with high resilience against disasters. We hope to continue such joint exchanges between Japan and Korea in the future, so that we can work together to take steps toward better cultural property preservation.
Lecture on scientific investigation
Lecture on air conditioning
Lecture on preservation of large volumes of documents
Tour of the laboratories
The “Training Course for Museum Curators in Charge of Conservation (Advanced Course) in 2024” was held from July 10 to 14, 2024. This training course, which has been held at the Tokyo National Research Institute for Cultural Properties since 1984, was reorganized into a “Basic Course” and an “Advanced Course” in 2021, with the aim of enabling curators in charge of conservation at museums to acquire a wide range of knowledge and skills necessary for their work, from basic to advanced.
The “Basic Course,” conducted by the National Center for the Promotion of Cultural Properties, is designed to provide curators in charge of the conservation environment in of museums with a wide range of knowledge and skills.
The “Advanced Course” covers not only the conservation environment, but also general conservation of cultural properties, and is conducted by the Center for Conservation Science. In the 2024 Advanced Course, lectures and practical training based on research results in various research fields were conducted by the Center for Conservation Science, and lectures on the conservation and restoration of various cultural properties were provided by external lecturers. This year in particular, some of the lectures covered information on cultural property rescue in relation to the Noto Peninsula earthquake. The themes of the lectures and practical training were as follows:
・Theory of restoration of cultural properties
・Scientific investigation of cultural properties
・Air quality (about air quality / effects of air pollution on cultural properties / concepts of ventilation)
・Theory and practice of storage environment (air conditioning)
・Introduction and practice of Integrated Pest Management (IPM) for cultural properties
・Types and characteristics of restoration materials
・Deterioration and conservation of outdoor materials
・Protection of heritage of modernization
・Conservation and restoration of various cultural properties
・Disaster prevention in museums
・Conservation and restoration of folk artifacts
・Preservation of large volumes of documents, and countermeasures against deterioration
・Conservation and restoration of works on paper
・Preservation and management of photographs
Participants commented that the training was a great support for their future activities, that they were able to deepen their knowledge of the issues they are facing, and that by coming into contact with a wide range of content, they were able to gain perspective for comprehensive consideration of environmental management and disaster prevention at their affiliated museums. This year, an opinion exchange meeting was held after the first day. Through self-introductions, participants shared their enthusiasm for the training and the issues facing their respective museums. Through this training, participants were able to interact with curators from facilities other than those in nearby prefectures, and it appeared to be a fulfilling training experience.
Conducting an on-site inspection.
The bell tower of Okariden Hall.
On May 15, 2024, we visited Nikko Toshogu Shrine to inspect the “humidity-controlled warm-air treatment” facilities for the bell tower of Okariden Hall. Traditional gas fumigation for insect extermination has become difficult to continue due to safety and environmental concerns. This new treatment is a method to exterminate insects that damage the wood of structures, such as pillars and beams, by heating the wood to high temperatures (around 60℃). By controlling the humidity during the treatment to maintain a constant moisture content in the wood, it is possible to raise the temperature inside the wood without significantly affecting its physical properties. The new method is therefore expected to be a means to replace gas fumigation.
To date, the research team, consisting of the Association for the Preservation of the Nikko World Heritage Site Shrines and Temples, Kyoto University, Total System Laboratory, Kansai Electric Power Co., Inc., KANSO Technos Co., Ltd., and the Tokyo National Research Institute for Cultural Properties (TOBUNKEN), has conducted three verification treatments on actual buildings. In addition to evaluating the insecticidal effects and impact on the structures, considerations were also given to environmental impacts such as noise and energy consumption. As a result, the humidity-controlled warm-air treatment was established as a practicable new method for insect extermination in wooden structures.
Last year, for the first time on a designated cultural property, the treatment was carried out at the Gohotendo Hall of Rinnoji Temple. This time, it was conducted at the bell tower of Okariden Hall, marking the second case for a designated cultural property. Going forward, we aim to promote this method as the new standard for insect extermination in wooden structures.
Search using morphological features as key words
In April 2024, a new function, “Cultural Property Pest Search” (https://www.tobunken.go.jp/ccr/pest-search/top/index.html) was launched on the TOBUNKEN website. This function helps users to identify cultural property pests when they are found.
There are many different types of cultural property pests, and it has been difficult for people who are not insect specialists to identify them. However, these pests become apparent, and there was a need to develop a tool to assist with their identification on the spot. In response to this need, this search page has been created to enable anyone to easily identify the cultural property pests.
The “Cultural Property Pest Search” page is a web-based content search engine that can be browsed from a smartphone, so that cultural property pests can be examined immediately at the site where they are found. The search algorithm is based on morphological information such as the shape and color of the insect, which can be determined on the spot, so even if users are not familiar with insects, they can intuitively examine the pest. In addition to information on morphology and ecology, the pages returned for each pest contain many photographs from various angles for easy comparison with the insects found. The pages also contain useful information for research on cultural property pests, such as genetic information and related papers.
As of May 2024, the “Cultural Property Pest Search” content lists 30 of the 150 known major species of cultural property pests. We will continue to expand the database to include more species in the future.
Screenshot of the painted silk database user interface
Digital microscope photograph
Silk has been a traditional support material for Japanese and other Eastern paintings since the Tang Dynasty in China, which corresponded to the Heian period in Japan. Silk has been used mainly in clothing in East Asia from ancient times to the present. Although ancient silk clothing is rarely preserved, due to consumption, examples of painted silk have been handed down in better condition. Painted silk works can be compared in terms of their woven structure and fiber shape, as most of them were plain woven. The study of the woven structure and fiber form (composed of silk thread) of painted silk is an important research issue, not only for art historical research, but also for the history and transition of materials and techniques.
The Tokyo National Research Institute for Cultural Properties (TOBUNKEN), established a “Memorandum of Understanding (MOU) of the Joint Research on the Composition of Silk Painting Supports and Other Textiles Used in Artworks” with the Tokyo National Museum in 2019. As a part of the research, photography and measurement of silk paintings is being conducted using a digital microscope (HiRox RH-2000), focusing on works in the Tokyo National Museum’s collection.
We are pleased to announce that a database of the results of this project is now available as the “Tokyo National Museum Digital Research Archives,” in cooperation with the Infomatics Division of the Tokyo National Museum, accessible through the website below.
https://webarchives.tnm.jp/infolib/meta_pub/G0000002221214GK
The database contains images of important works such as the National Treasure “The Bodhisattva Fugen,” “The Biography of the Traveling Preacher Ippen,” and “Red and White Cotton Rosemallow” by Li Di, as well as images of the woven structure and the measured data of the fiber shape. We plan to add more works to the database in the future. We will use this database to promote research on works and material techniques.
A group photo of the symposium participants
For the purpose of discussing science for cultural heritage and building new research collaborations between France and Japan, a symposium titled “French-Japanese Workshop on Material Sciences for Cultural Heritage” was held on March 13 in 2024 in the seminar room of the Tokyo National Research Institute for Cultural Properties (TOBUNKEN). The seminar was co-organized by the Embassy of France in Japan, the National Center for Research and Restoration in French Museums, the Foundation of Science for Cultural Heritage, and TOBUNKEN.
The program of the symposium consisted of five sessions: ceramic, paper, wood, painting, and environment/sustainable conservation. On each topic, lectures were provided by French and Japanese researchers, followed by discussions. Also, a lively panel discussion followed the five sessions and went beyond a summary of the symposium to include future prospects for the sciences for cultural heritage (Participants: 61, including 8 French researchers).
A closed roundtable meeting was held on March 14 with participation of all the speakers and moderators of the symposium. Fruitful discussions were held for establishing new research collaborations concerning sciences for cultural heritage between French and Japanese experts.
Workshop venue
This seminar was jointly held by the National Center for the Promotion of Cultural Properties and Tokyo National Research Institute for Cultural Properties with the aim of gaining a common understanding of the specialized survey and evaluation methods used for the conservation environment for cultural properties, as well as of the materials and tools used in improving storage environments or providing safe storage.
The 7th meeting, titled “Sustainable Environmental Management in Consideration of Global Warming” was held on March 1, 2024, in a conference room of the National Center for the Promotion of Cultural Properties. Dr. MIZUTANI Etsuko, a researcher with the Cultural Heritage Disaster Risk Management Center, joined in an international workshop, “Changing Climate Management Strategies Workshop” held in Melbourne, Australia, in August 2023. She shared the contents of the workshop, identified issues in this seminar, and held discussions. She talked about the outlook of the workshop, held in response to the global climate change crisis, which has increased the worldwide need to conserve and utilize cultural heritage in more sustainable ways. Lectures, practical training, and discussions were held on the issues and solutions to be implemented in museums around the world. In particular, in a lecture on the historical background of management of the conservation environment for cultural heritage, changes to the guidelines for the temperature and humidity of conservation environment were shown as essential for promoting sustainable management strategies in the future. At the same time, a lecture was held on risk assessment and monitoring methods for cultural heritage, and on the last day, there were reports and discussions about individual cases; thus, it was a very dense workshop.
While participating in the workshop, Dr. MIZUTANI presented the participants with an issue concerning the impact of global warming on the conservation environment, and raised the subject of management of the conservation environment, and how to proceed with management strategies in Japan. There were five curators in charge of conservation or experts in conservation science at the venue in person, and 12 such persons participated in the seminar online, and these participants posed various questions related to the fundamentals of the conservation environment.
This seminar was a good opportunity to learn about overseas trends in environmental management for the sustainable preservation of cultural properties, and to reconsider how to deal with global warming and management of the conservation environment in Japan.
In FY2023, the Center for Conservation Science introduced a microtome, a biological microscope (with polarized light, phase contrast, and differential interference observation functionality), and an infrared microscope (Fig. 1). The following is an introduction of these newly introduced instruments.
Microtome
The microtome is a device used to precisely cut samples to facilitate observation. For example, when analyzing what kind of material a piece of paper or cloth is made of, a sample is sometimes cut and its cross section is observed under a microscope. Conventionally, samples are cut with razor-sharp blades or embedded in resin and polished. However, these methods can present problems such as deformation of the specimen and difficulty in observing the specimen because it is embedded in resin, and they require skillful manipulation. The microtome solves these problems and makes it easier to identify paper and cloth materials. Figure 2 shows an example of actual cross-sectional observation results. The microtome can be applied to all cultural assets made of organic materials such as wood and lacquerware.
Biological Microscope
Polarized light observation, phase-contrast microscopy, and differential interference microscopy are effective for observing crystal structures, microstructures, and cells and biological tissues, respectively. For example, they are effective for observing mold and bacteria on cultural properties, fibers of paper and textiles, and starch glue and other glues used for cultural properties.
Infrared microscope
Infrared cameras are often used to observe cultural properties. This type of microscope can be used to clearly see ink lines and certain types of dyes used in calligraphy and paintings, and to identify materials and observe the underlying surface of paintings.
We will continue to analyze cultural properties using these devices.
Figure 1. Photographs of newly introduced instruments
Microtome
Biological microscope
Infrared microscope
Figure 2. Cross section of Najio Gampi paper
Cross-section produced using a scalpel
Cross-section produced using a microtome
When a scalpel is used to produce a cross section, a large amount of clay minerals are pressed down by the blade, covering the gampi fibers and causing them to lose their original shape. When the cross section is produced with a microtome, the gaps between fibers can be confirmed, and the hollow structure of the fibers remains intact.
Presentation
Panel discussion
Exhibition
On January 23, 2024, the Center for Conservation Science of the Tokyo National Research Institute for Cultural Properties (TOBUNKEN) held an open seminar, titled Conservation and Utilization of Aerial Heritage, in cooperation with the Japan Aeronautic Association (JAA).
Aerial heritage, including materials related to aviation history such as drawings and photographs, are irreplaceable cultural properties in Japan’s modern and contemporary history. However, there are many differences from conventional cultural properties in terms of materials and scale, and new methods are often required for their conservation and utilization as cultural properties. The purpose of this open seminar was to rethink the current status and issues of aviation materials as cultural assets and cultural heritage.
The opening remarks were made by Mr. SAITO Takamasa, Director General of TOBUNKEN, and Mr. SHIMIZU Shinzo, Vice President of the JAA, followed by an explanation of the purpose of the seminar by Mr. NAKAYAMA Shunsuke, Senior Fellow of the Center for Conservation Science. Mr. NAKAYAMA, Mr. KANDA Shigeyoshi of JAA, and Ms. NAKAMURA Mai, Associate Fellow of the Center for Conservation Science, gave a presentation titled “Preservation of Aviation Historical Materials and Challenges” on the results and challenges of the joint research project, “Study on the Preservation of Aviation Heritage,” that the JAA and the TOBUNKEN have been carrying out since FY2004. Mr. NAGASHIMA Hiroyuki, a former member of the JAA, gave a detailed case study report on the repair of the fabric coverings of the Type 3 Fighter “Hien,” owned by the JAA and exhibited at the Gifu-Kakamigahara air and space museum. Mr. YAMAKI Satoshi of the Chiran Peace Museum for Kamikaze Pilots in Minamikyushu City reported on the history of the Type 4 Fighter “Hayate (No. 1446),” owned by the museum, and the research activities being undertaken to preserve it. In addition, Mr. CHIBA Tsuyoshi, Researcher of the Center for Conservation Science, and Ms. HAGA Ayae Researcher of the Center for Conservation Science, gave a presentation on the status of the designation of aircraft as cultural properties in Japan and introduced the research that has been conducted as part of the “MoU for Research on Conservation and Restoration of Cultural Properties Designated by Minamikyushu City.” Following these lectures, a panel discussion was held with Mr. KANDA, Mr. NAGASHIMA, Mr. YAMAKI, and Mr. NAKAYAMA, with Mr. TATEISHI Toru, Director of the Center for Conservation Science, as a facilitator, in which participants actively exchanged opinions on the current status and issues surrounding aviation materials as cultural properties. The event ended on a high note with closing remarks by Mr. TATEISHI.
In the foyer of the venue, we exhibited materials related to the joint research between the JAA and TOBUNKEN, including a horizontal stabilizer of a Yamazaki Type 1 “Wakamoto” glider, the vertical stabilizer of an Ito Type A2 glider, an oil painting called “Asakaze” by YAMAJI Shingo, and a Siemens-Schuckert D.IV fuselage panel.
In all, 77 people participated in the seminar, and the post-event questions showed that there are high expectations for research and study on the preservation and utilization of modern cultural heritage, including aircraft. A report on this seminar will be published in the next fiscal year.
Home page of HERIe website
Professor Łukasz Bratasz giving a lecture
Lecture by Dr. Michal Lukomski
Scene from the workshop
A workshop on “Sustainable Risk Management for Collection in Museum, Utilization of HERIe Digital Preventive Conservation Platform” was held jointly by the Department of Conservation of the Graduate School of Fine Arts at the Tokyo University of the Arts, the Cultural Heritage Disaster Risk Management Center, and Tokyo National Research Institute for Cultural Properties (TOBUNKEN), on December 17, 2023.
The HERIe Digital Preventive Conservation Platform (https://herie.pl/Home/Info) is designed to support the collaboration between museum curators and conservation professionals when assessing the conservation conditions and safety of collections for display. It is a decision-making support platform that provides a quantitative assessment of risks to collections. At the moment, it includes modules that address environmental degradation factors such as air pollutants, lighting, inappropriate temperature, and relative humidity, and modules that allow estimation of fire hazards. The platform is being developed by several institutions with financial support from the European Commission and the Getty Conservation Institute.
The purpose of this workshop was to give museum conservators and restoration professionals experience with the use of the data of their own museums on the platform. It was a very good opportunity to invite teachers from overseas who are among the developers of this platform to hear directly about its effectiveness and how to use it, and to try it out in a classroom. As an introduction, Prof. Łukasz Bratasz of the Polish Academy of Sciences introduced the platform and explained the concept and structure, and introduced the topic of pollutants and chemical degradation in museums and galleries. Next, Dr. Michał Łukomski of the Getty Conservation Institute talked about modelling mechanical damage and using the tool to assess museum climates. Prof. Boris Pretzel (Invited Professor of Conservation Science at Tokyo University of the Arts) introduced the topic of the light degradation tool and the presentations finished with Prof. Bratasz explaining the tool for fire risk assessment. Other tools, such as the showcase tool, were also introduced and demonstrated during the day, giving all delegates a good introduction of the kind of information each tool can provide.
Many of the participants commented that they had deepened their understanding of the platform, with remarks such as that they wanted to return to the museum and use it because they learned about a very useful tool, and that they wanted to use it to assess light damage when they brought their collection to the restoration studio.
Since this platform is provided free of charge, we hope that it will be widely used both by those who participated, and those who could not participate in the workshop.
A historic building damaged, collapsed, and temporarily closed. (Hatay)
Restoration of the collapsed walls is underway at Gaziantep Castle.
Experts' seminar
The Tokyo National Research Institute for Cultural Properties (TOBUNKEN) participated in the Emergency International Contribution Project for Cultural Heritage in FY2023 commissioned by the Agency for Cultural Affairs, Government of Japan, which was titled as “Project for supporting the Reconstruction of Damaged Cultural Heritage in Türkiye,” in cooperation with the Cultural Heritage Disaster Risk Management Center, Japan (CHDRMC).
The primary objective of this project was to provide relief support for museums and cultural heritage damaged in the 2023 Türkiye–Syria earthquakes that occurred on February 6, 2023. In addition, by sharing Japan’s experience in rescuing damaged cultural heritage and our accumulated knowledge of cultural heritage disaster prevention with Türkiye, the project also aims to support the establishment and enhancement of a cultural heritage disaster prevention system in Türkiye.
From November 28 to December 7, 2023, a joint team of TOBUNKEN and CHDRMC visited Türkiye to investigate the affected areas, exchange information on cultural heritage disaster prevention in both countries, and exchange opinions with their Turkish counterparts for future collaboration.
The team visited museums and cultural heritage sites in Hatay, Gaziantep, and Şanlıurfa to ask museum staff about the response to the disaster, the current situation, and other issues, and to survey future support needs. At present, emergency measures are almost completed at the damaged museums, and full-scale work for recovery of the damaged collections and buildings is expected to be carried out in the near future. The museum in Şanlıurfa was flooded by heavy rains in early March, one month after the earthquake.
The experts’ meeting was held at the Ministry of Culture and Tourism, Republic of Türkiye, jointly with the Ministry. The Japanese side provided an overview of cultural property disaster prevention systems in Japan, and reported on activities to rescue cultural properties damaged in the Great East Japan Earthquake and other recent disasters, as well as disaster prevention measurements at museums. The Turkish side reported on the damage to cultural properties caused by the earthquake, presented an overview of the response, and discussed disaster risk mitigation methods at museums. The parties from the two countries are continuing with further discussion regarding the direction of specific mutual collaboration and promotion of joint research on cultural property disaster prevention.
A presentation by a participant
Kongju National University, the venue of the event
Mr. CHIBA Tsuyoshi, Researcher of the Center for Conservation Science, participated in the 58th Autumn Conference of the Korean Society of Conservation Science for Cultural Heritage held at Kongju National University, South Korea, on November 10-11, 2023.
In recent years, interest in the protection of modern cultural heritage has been increasing in South Korea. At the conference, a special session entitled “Research on Establishment of Standard Specifications for Conservation Treatment of Nationally Registered Cultural Properties (Movable Property) (1st round)” (hosted by the Cultural Heritage Administration and chaired by Dr. KIM Gyu-Ho, Kongju National University) discussed what kind of systems and conservation methods should be used to protect modern cultural heritage.
Under the title of “Overview and Examples of Modern Cultural Heritage Protection in Japan,” Mr. Chiba reported on the current status of modern cultural heritage protection in the Japanese cultural property protection system, and outlined the characteristics of modern cultural heritage and the technical, theoretical, and institutional issues involved in its preservation.
The modern era (Meiji era of Japan; late 19th to early 20th century) was a time of internationalization in many parts of the world, and in Japan, cultural heritage produced during this period often incorporates new materials and techniques brought from abroad. In addition to the diversification of materials and techniques, there are many unique aspects of modern cultural heritage, such as the “large number of industrial products,” and “many items still in use today.
In addition to domestic research, international exchange is also important for the preservation of modern cultural heritage, which uses many common materials that transcend national borders, in contrast to traditional materials and techniques that are based on regional characteristics. We would like to continue to learn from each other’s efforts in both countries and deepen our research and exchange.
Mr. Saito and Mr. Yamaguchi at the agreement signing ceremony
An exhibition on noriutsugi with panels and a documentary movie
The Tokyo National Research Institute for Cultural Properties (TOBUNKEN) and the government council of Shibetsu Town, Hokkaido Prefecture, concluded an agreement on collaboration and cooperation, and conducted a conclusion ceremony on November 2, 2023. Though production of noriutsugi* was almost lost, the people of Shibetsu Town is now working on its revival, as an official town project. This agreement is aims to promote discussion on appropriate ways to preserve and store produced noriutsugi; interaction for scientific identification of the characteristics of neri (dispersant) extracted from noriutsugi barks and exchange and provision of any related information. Noriutsugi is a material used in the manufacture of uda washi paper, and is essential to conserve hanging scrolls. Success of the project in Shibetsu Town will lead to a sustainable and stable supply of the material.
Four members from TOBUNKEN, including the Director General, Mr. SAITO Takamasa, participated in the ceremony. The Mayor of Shibetsu Town, Mr. YAMAGUCHI Shougo, and Mr. SAITO each provided greeting remarks and signed the agreement.
After the ceremonial signature, the lecture session was conducted. Dr. TATEISHI Toru, Director of the Center for Conservation Science, TOBUNKEN, conducted a lecture titled The Important Role of Shibetsu Town on Cultural Property Protection in Japan about the tight relationship between cultural property protection and Shibetsu Town, including the management of the Ichani Karikariusu Historical Site. Afterwards, Dr. HAYAKAWA Noriko, Head of the Restoration Materials Section of the center, spoke about the importance of Shibetsu Town for noriutsugi-neri production in a lecture titled Cultural Property Restoration and Noriutsugi.
At the venue of the lectures, an exhibition related to noriutsugi and uda washi paper with related materials, panels, and documentary movies used for TOBUNKEN lobby exhibition was held. Many participants attended across the Town.
We also visited the noriutsugi planting site before and before the ceremony. We expect that further research and exchange with the people involved at the site will lead to an outcome beneficial to cultural property restoration.
*Noriutsugi-neri, a component used as a neri (dispersant), for traditional papermaking (uda washi), has been produced by barking and extracting from wild noriutsugi plants (Hydrangea paniculate); however, it has become difficult to keep producing it in the traditional way. Therefore, an attempt to produce a sustainable supply of noriutsugi-neri product by systematically harvesting noriutsugi for barking, and scientific studies are on-going.
