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

Publication of Painted Silk Database of Paintings in the Tokyo National Museum Collection

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.

 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.

French-Japanese Workshop on Material Sciences for Cultural Heritage

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.

The 7th Seminar on Research and Management regarding the Conservation Environment for Cultural Properties – Sustainable Environmental Management in Consideration of Global Warming –

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.

Newly introduced instruments at the Center for Conservation Science in FY2023

 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.

 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

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.

Open seminar: “Preservation and Utilization of Aerial Heritage”

Panel discussion

 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.

Workshop on the HERIe Digital Preventive Conservation Platform

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 ( 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.

Field Survey in Türkiye for the Rescue of Museums and Cultural Heritage Damaged in the 2023 Earthquake

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.

Participation in the 58th Autumn Conference of the Korean Society of Conservation Science for Cultural Heritage

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.

Conclusion of Agreement on Collaboration and Cooperation on Production of Raw Materials to Conserve Cultural Properties with Shibetu Town, Hokkaido Prefecture

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.

The 15th International Conference of the Infrared and Raman Users Group (IRUG)

IRUG group photo
A practical research workshop

 The 15th International Conference of the Infrared and Raman Users Group (IRUG) was held for the first time in Asia, at the Tokyo National Research Institute for Cultural Properties (“Tobunken”) from September 26 to 29, 2023, in collaboration with the Conservation Science Laboratory of Tokyo University of the Arts (“Geidai”).
 IRUG is establishing a forum for the exchange of infrared and Raman spectroscopic information and reference spectra for the study of the world’s cultural heritage. Both FT-IR and Raman spectroscopic analytical methods are very effective for determining material information when surveying cultural properties. In recent years, the investigation of cultural properties using these analytical methods has progressed, and many results have been reported.
 There were 51 oral and poster presentations at the international conference. The keynote talk, covering aspects of the theory and challenges of reflectance-mode infrared spectroscopy, was given by Dr. James A. de Haseth, Professor Emeritus of Chemistry at the University of Georgia (USA). A featured workshop covering reflectance infrared spectroscopic techniques, with focus on data acquisition, processing, and interpretation, was led by Dr. Marcello Picollo (Senior Researcher at IFAC-CNR) and aided by Dr. Suzan de Groot (RCE, The Netherlands), Prof. Manfred Schreiner (Akademie der Bildenden Künste, Austria), with sponsorship and other aid from Thermo Fisher Scientific Corporation, and Bruker Corporation.
 Throughout the conference, active discussions were held on methods of analysis and conservation of cultural property materials. The Center for Conservation Science will continue to observe international trends as it works to advance our research projects.

Workshop on Restoration Treatments for Cultural Property – The Modular Cleaning Program Workshop

With participants after the opening ceremony

 The Center for Conservation Science regularly holds workshops inviting leading experts from outside of Japan, having started with Workshop on Restoration Treatments for Cultural Property – Cleaning with Gels and Emulsions in 2019.

 In FY 2023, with the invited guest Mr. Chris Stavroudis, American instructor, painting conservation expert, we cohosted a workshop with the National Center for Art Research on October 25 to 27, 2023, called “The Modular Cleaning Program Workshop.” In this program, the elements necessary for cultural property cleaning are determined using a unique system. This program is now widely used in the Western countries because of its good usability. This workshop was the first of its kind that he has lead in Asia, and attracted many participants.

 The workshop details are now available on the website of the National Center for Art Research:

Participation in the International Training Course “Leadership Course for Cultural Heritage Stewards in Challenging Circumstances”

Lecture on funding(Photo by Almicheal Fraay)
A presentation by a participant
Participants, teachers, and coordinators at a certification ceremony held after the training(Photo by Almicheal Fraay)

 Mr. CHIBA Tsuyoshi, Researcher of the Center for Conservation Science, participated in the “Leadership Course for Cultural Heritage Stewards in Challenging Circumstances” held in The Hague, the Netherlands, from September 24 to 29, 2023.
 This training course was organized by Cultural Emergency Response ( and the Smithsonian Cultural Rescue Initiative ( It has been held annually since 2018, and this was the fifth session. This year there were 14 participants including Mr. CHIBA, who was the first from Japan. Among the others, there were two from Ukraine, and one each from Afghanistan, Barbados, Cameroon, Georgia, Lesotho, Namibia, Nigeria, Peru, Turkey, USA, and Vietnam.
 The training had two main aspects: “planning and proposal” and “team planning and management,” with lectures given by experts in each field. In the planning and proposal training, participants developed plans and project proposals related to the protection of cultural heritage in challenging circumstances, and effective short presentations to persuade external organizations to provide funding and support. On the final day of the training, the participants presented their projects to an audience of four representatives of the actual funding agencies, who answered their questions, offered suggestions for improvement, and critiqued them. The training in team planning and management included analyzing the “strengths” of team members and developing ideas that complement each other, leadership skills for effective team management, and attitudes for maintaining healthy mental health.
 In Japan, it seems that there has not been much interest in funding related to the protection of cultural properties, and there have been few training programs regarding this subject. However, as the situation surrounding cultural properties changes in various ways, we believe that this type of training will become increasingly important for the future protection of cultural properties and disaster prevention of cultural properties. We plan to share the contents of this training course widely in the near future.

Workshop on Basic Science for Conservators in 2023

The participants just after the opening session
A lecture in progress

 The Center for Conservation Science conducts scientific research on the conservation and restoration of cultural properties. Since FY 2021, based on our research, we have held annual workshops on basic science for conservators who have diverse experience in the restoration of cultural properties and museum curation and archiving.

 In 2023, the workshop was held for three days, from August 22 to 24. We provided lectures and practical sessions on basic scientific knowledge essential for conservation and restoration, including basic chemistry, science of adhesion and adhesives, chemistry of paper, pest damage control, and usage and disposal of chemical agents. Researchers of the Tokyo National Research Institute for Cultural Properties delivered lectures based on their expertise.

 We received 32 applications from across Japan for 15 workshop seats. Though it is unfortunate that we could not accept all, as the workshop included practical sessions, we invited 21 applicants among them. In responding to feedback received from the previous year, we tried to plan more practical contents for 2023. Participants expressed their appreciation for this workshop through the questionnaires provided. We received specific requests for disseminating scientific information used in actual conservation and restoration cases. We intend to continue this workshop series to meet these expectations.

2023 Training Course for Museum Curators in Charge of Conservation (Advanced Course)

Lecture on air conditioning
Lecture on outdoor materials
Practical training for identification of cultural property pests
Tour of the laboratories

 The “Training Course for Museum Curators in Charge of Conservation (Advanced Course) in 2023” was held from July 10 to 14, 2023. This training course, which has been held at the Institute 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” is designed to provide curators in charge of the conservation of materials at museums with a wide range of knowledge and skills, from the basics to the practical. The course focuses on the conservation environment and is conducted by the National Center for the Promotion of Cultural Properties.
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 2023 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. On the first day, a tour of the center was conducted. 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 air quality improvement and 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 (rescue of cultural properties / environmental management of temporary storage facilities / daily cultural heritage disaster prevention in museums)
・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

 A post-training questionnaire indicated a high level of satisfaction throughout the training. Some participants commented that they were able to gain practical knowledge in a systematic manner and that they were stimulated by learning about cutting-edge research. On the other hand, we also received some comments that they would like more time for training and some requested future follow-up. We will continue to review the content of the training to ensure that it is beneficial to curators in charge of conservation.
Last year, due to restrictions imposed for protection from the spread of COVID-19, the number of participants was only 18, but this year there were 30 participants, as the infection situation had calmed down somewhat.
Although the participants come from a wide variety of institutions, they all share similar concerns and awareness of the problems they face in the field, and we believe that the exchange of ideas and opinions among the participants is very meaningful. We hope that the networking that participants were able to take part in during this training will also be useful in the future.

Study for a Stable Supply of Noriutsugi (2)

 In our December 2022 Monthly Report, we reported on the “neri,” a sort of “dispersant” used in papermaking, extracted from noriutsugi (Hydrangea paniculate). This report is a continuation of that previous report.
 Since last year, noriutsugi collected in Shibetsu-cho, Hokkaido Prefecture has been shipped to various papermaking areas and used as neri for papermaking, but problems such as blackening of the neri have been observed in some areas. Analysis of the causes of the blackening confirmed that it is caused by a combination of three conditions: heating during neri extraction, contamination of tannins in the outer bark, and the absence of preservatives. Therefore, the blackening can be eliminated by carefully removing the outer bark or by adding a small amount of preservative. This result was reported at the 45th annual meeting of The Japan Society for the Conservation of Cultural Property (National Museum of Ethnology, June 24-25), and the presentation was very fruitful, receiving many questions.
 In addition, we visited the production sites of Uda paper (Yoshin-cho, Yoshino-gun, Nara Prefecture) and Echizen washi (Echizen-shi, Fukui Prefecture), which are made using noriutsugi, in succession (March 6 for Uda and July 19 for Echizen) and conducted a survey of the paper-making process. In both of these production areas, the shortage of noriutsugi is a major problem, and the supply from Shibetsu-cho is expected to be of great help. It was also confirmed once again that there are different ways to use noriutsugi neri depending on the production area and the craftsman, and it is necessary to consider supply methods that meet the needs. In addition, on July 27, we visited Shibetsu-cho to observe the collection of noriutsugi bark, to study the collection method and to record and photograph the process. This year, about 200 kg of noriutsugi bark has already been collected and shipped to various papermaking regions.
 We will continue our activities to ensure a stable supply of noriutsugi.

Visiting papermaking sites

Uda-gami papermaking, using noritsugi from Shibetsu-cho

Noritsugi used for Echizen washi
Visit to Shibetsu-cho

Noriutsugi, which grows wild in large quantities in Shibetsu-cho

Collecting bark

Panel Exhibition in the Entrance Lobby: Current Status of Tools and Raw Materials Essential for Cultural Property Restoration

Exhibition talk
Exhibition in the entrance lobby

 Tokyo National Research Institute for Cultural Properties (TOBUNKEN) is exhibiting panels in its entrance lobby to disseminate its research outcomes. We started the new panel exhibition named in the title on June 5, 2023.
 Techniques for conservation and restoration are essential to pass cultural properties down to the future generations. However, the acquisition of more types of materials and tools necessary for these techniques is becoming difficult, because of a shortage of successors to make them as well as changes in social environment. Due to its urgency, we are conducting investigational research on these tools and materials in collaboration with the Agency for Cultural Affairs. We are working to clarify the materials used and to improve issues related to their use, from a scientific standpoint, to comprehend methods to use these materials and tools on the conservation, and to record the techniques of their manufacture. We comprehensively conduct both the investigations above and archiving of past restoration documentation reports.
 This project involves various activities and sectors, and we are therefore conducting this project cross-sectorally across TOBUNKEN, utilizing the strength of TOBUNKEN in that has multiple sectors to facilitate comprehensive research on cultural properties.
 The exhibition mainly involves the raw materials of Uda washi paper essential for hanging scroll mountings and the carving tools essential for sculpture restoration. As neither are replaceable with substitutes, the continuation of their supply is in danger, and on this basis, we chose them as our research target. TOBUNKEN, and particularly the Center for Conservation Science, has been working on scientific research on traditional materials in Japan even since before this project started. The outcomes of the research are also exhibited. We hope that you can experience the in-depth world of materials and tools related to cultural property restoration and the wide outcomes of the research through this exhibition.

(Free entrance. Open 9:00 – 17:30 from Monday to Friday (except for national holidays).

Survey for the conservation and restoration of an early 20th century aircraft

Confirmation of paint stain removal status
Confirmation of surface using microscope
3D model obtained by SfM-MVS

 Unlike ancient cultural heritage items created using traditional materials and techniques, many modern cultural heritage items were created using relatively new technologies brought to Japan after the Meiji period (1868-1912). Furthermore, modern industrial products created for mass production and mass consumption are generally difficult to preserve over the long term. One of the research themes of our laboratory is how to preserve cultural heritage from such a relatively recent era for the future.
 In March 2023, we conducted a survey of aircraft components from the 1910s stored and displayed at the Matsuiya Sake Brewery Museum (松井屋酒造 Tomika-cho, Gifu Prefecture). The survey aimed to collect information about the appropriate preservation method and the direction of utilization of the materials, following an actual inspection of and discussion about the materials with the Tomika-cho Board of Education, the Matsuiya Sake Brewery Museum, and others in May 2022.
 The surveyed part is believed to be the horizontal tailfin of a French Salmson Model 2 double-seat reconnaissance aircraft (Salmson 2A2), manufactured by another company in France under license from Salmson(YOKOKAWA Yuichi, “On the Salmson 2A2 Fuselage Parts Remaining at the Matsuiya Brewery,” Aviation Fan, December 2021). In 1918, at the end of World War I, the Japanese Army purchased 30 of these planes, and it is estimated that the material kept at the Matsuiya Sake Brewery Museum comes from one of them.
The paint is visible on the entire front and back of the tailfin. It is highly likely that it is the original paint from the 1910s, and if so, it may be the only aircraft component in the world that still has the original paint from that period (YOKOKAWA, above).
 To examine the possibility of conservation and restoration and its methods, we checked stain removal status with partial dusting and the removal of dirt using water and other methods. With the cooperation of the repair technician, we confirmed that there was a high probability that the original paint was still extensively in place and discussed specific cleaning methods.
 Although the survey confirmed which cleaning method is to be used, many points still need to be considered in its implementation. We will continue to work with the Matsuiya Sake Brewery Museum, Tomika-cho Board of Education, and other concerned parties to find solutions for the preservation of the aircraft components.

Commemorative Symposium for the Retirement of Two Deputy Director Generals
“New World of Cultural Properties Brought about by the Development of Analytical Chemistry: Colors and Varieties”

Flyer for the symposium
The keynote lecture by Deputy Director General HAYAKAWA
The keynote lecture by Deputy Director General KOHDZUMA
Panel Discussion

 In recent years, developments in analytical chemistry have led to the discovery of new values of cultural properties.
 On March 4, a symposium was held to commemorate the retirement, in March 2023, of HAYAKAWA Yasuhiro, Deputy Director General of Tokyo National Research Institute for Cultural Properties (TOBUNKEN) and KOHDZUMA Yohsei, Deputy Director General of Nara National Research Institute for Cultural Properties (NABUNKEN) who have, for the long time, contributed to the scientific research and conservation of cultural properties. The symposium aimed to discuss the new world of cultural properties opened up by the development of analytical chemistry from the perspective of “color,” one of the most fundamental and important values of cultural properties. The event was organized by TOBUNKEN and NABUNKEN, and co-sponsored by Nittetsu Technology Co.
 The symposium was held in the seminar room of TOBUNKEN, and many participants also gathered at the satellite sites of TOBUNKEN and NABUNKEN (Participants: 69 [TOBUNKEN seminar room], 36 [satellite site of TOBUNKEN], 26 [satellite site of NABUNKEN]). The symposium was also simultaneously streamed on YouTube, and was watched by many people.
 In the keynote lecture by Deputy Director General HAYAKAWA entitled “Transition of White Pigments in Japanese Paintings,” the presentation showed the transition of white pigments (lead white, artists’ chalk, and white clay) used in Japanese paintings based on the results of his analytical surveys.
 In the keynote lecture, “Across the Boundaries ,” Deputy Director General KOHDZUMA spoke about the importance of conducting research with a broad perspective and mutual understanding while honing one’s own expertise in the field of conservation science of cultural properties. In addition to the keynote lectures, there were seven research presentations related to the “color” of cultural properties and an exhibition of various analytical instruments during the lunch break. Also, the lecture was followed by a lively panel discussion that went beyond the topic of color analysis of cultural properties to include future prospects of the conservation science for cultural properties.
 We are thankful for the leadership of the two Deputy Director Generals which greatly helped the staff of TOBUNKEN, NABUNKEN, and Nittetsu Technology to collaborate with each other effectively and plan and conduct a very successful symposium.

Installation of a lid aimed at preventing the accumulation of dust on the wall paintings of the national treasure Kitora Tumulus

Lid delivery
Lid in place (east wall)

 The Kitora Tumulus Mural is a national treasure that depicts the four deities, the twelve signs of the Chinese zodiac with beast heads and human bodies, and astronomical images. It has been repaired after it was removed from the inside of the tomb, and is now stored with the mural face up at the Kitora Kofun Mural Conservation and Management Facility in the “Hall of Four Deities” located in Asuka Village, Takaichi County, Nara Prefecture. Until now, dust has been prevented from entering the storage room using a dust remover in the front room. However, the visible dust on the wall painting that was brought into the room and could not be removed has been an issue for many years. As there is risk of damaging the mural when removing dust, the installation of a lid to prevent the accumulation of dust on the mural was considered. The Agency for Cultural Affairs, Tokyo National Research Institute for Cultural Properties, Nara National Research Institute for Cultural Properties, and the Association for Conservation of National Treasures (ACNT) have discussed the elements required for the lid, which does not adversely affect the mural, is easy to handle, allows the mural to be seen with the lid in place, and made of a material that does not attract dust. At the Kuroda workshop (Representative: Mr. USUI Hiroaki), a manufacturer of traditional fittings, whose technique is designated by the government as one of the Selected Conservation Techniques, a wooden frame covered with a transparent antistatic sheet was made as a prototype lid. Because it was confirmed in FY2021 that there is no difference in temperature and humidity inside and outside the lid, the possibility of adverse effects on the mural is extremely low. Thus, the finished product, with improvements in terms of strength, was delivered on March 24, 2023, and the lid was installed on the Kitora Tumulus Mural. We plan to confirm the effectiveness of the installation of the lid and discuss with the relevant parties how to handle the lid during mural inspections, public openings, and inspections.

Investigation of Modern Cultural Heritage in Minamikyushu City

Investigation of " Hayate"
The air quality Investigation
Filming of the former Chiran Airport water tower
Investigation of the former Aoto Airfield pillbox

 Tokyo National Research Institute for Cultural Properties (TOBUNKEN) worked with Minamikyushu City for “memorandum concerning the conservation and restoration of cultural properties designated by Minamiyusyu City”, and recently started joint research in July, 2022.
 The following surveys and investigation were conducted in Minamikyushu City in February, 2023.

Investigation and advice on preservation and restoration of the former Japanese Army Type 4 fighter “Hayate”
 The “Hayate” (designated cultural property of Minamikyushu City), which is stored and exhibited at the Chiran Peace Museum, was captured by the US military in the Philippines during the Asia-Pacific War and is the only surviving aircraft.
After a test flight by the US military, it was sold and passed through multiple owners before it was returned to Japan in 1973. When the town of Chiran (now Minamikyusyu City) was established in 1995, the aircraft was transported there and has been on display at the Chiran Peace Museum since 1997.
 Since 2017, Minamikyushu City has been conducting a conservation survey, and TOBUNKEN has participated in the survey from 2018. Our findings suggest that overall, the fuselage is in good condition, but some parts have worn out or been replaced because of the post-war test and demonstration flights. We will continue to check the status of the remaining original parts and consider the restoration policies. In this investigation, we mainly targeted the engine, checked the original parts, and the condition inside the engine and oil tank, among other things. Some parts removed from the aircraft were entrusted to TOBUNKEN for cleaning and component analyses.
 The research was conducted in the exhibition room. Since the exhibition room was not closed during the research period; visitors were able to observe it at that time. Additionally, a report on the state of preservation was published in March, 2022.

Air quality investigation of exhibition rooms and storage in the Chiran Peace Museum
 In this study, we conducted an air quality investigation (inspection of organic acids, aldehydes, and volatile organic compounds [VOC]) in the exhibition room and storage room along with a survey of ” Hayate.” In the future, we plan to consider a more stable exhibition and storage environment based on the results of this investigation.

Records of the current state of concrete structures during the Asia-Pacific War in Minamikyushu City
 Minamikyushu City has there are cultural assets related to numerous wars and the former Chiran Airfield. They have remained in the city since the Asia-Pacific War period. Many of them are concrete structures, but nearly 80 years have passed since the end of the war, and they are deteriorating and falling debris. In this study, we recorded the current situation by obtaining actual measurements and photogrammetry (three-dimensional models were created from multiple photographs) of the former Chiran Airfield water tower (a city-designated cultural property) and two pillboxes (defensive positions) of the former Aoto Airfield as concrete structures in the city during the relevant period. In the future, we will analyze the progress of deterioration based on regular records and consider measuring concrete strength.

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