| ■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 |
|
In 2020, the novel coronavirus (COVID-19) infection spread all over the world. On April 7, the Japanese government issued a state of emergency to seven prefectures, and on April 16, they expanded the target areas to all prefectures. Facilities possessing cultural properties also found it necessary to prevent the spread of the COVID-19 infection and then they encountered the concerns about the impact disinfection might cause to cultural properties. The Agency for Cultural Affairs issued an administrative contact on April 23, “Regarding the measures for virus removal and disinfection work to be taken by cultural property owners and administrators of facilities for the conservation and public display of cultural properties.”
The Agency warned the departments responsible for cultural properties across the country that disinfecting chemicals could cause deterioration of cultural properties, therefore some cases would require cautions in using those chemicals; and when any department faced the necessity of engaging in disinfection work for cultural properties and needed professional advice, it should consult the Agency beforehand. They asked the following three organizations — the Agency for Cultural Affairs, the National Center for the Promotion of Cultural Properties, and the Center for Conservation Science of Tokyo Cultural Properties Research Institute — to cooperate and provide the service as the consultation desk to respond to the situation. Our Institute has posted on its website that it is available to accept technical consultations regarding disinfection. (http://www.tobunken.go.jp/info/info200424/index.html).
So far, we have received a wide range of consultations including not only on disinfection in museums, art museums, exhibition rooms and storage of archives, but also on the disinfection of buildings as well as folk cultural properties used for festivals. In response to these consultations, our Institute has advised to minimize the usage of chemicals for disinfection and instead employ other infection prevention countermeasures. Even in cases absolutely requiring disinfection, we have advised on how to respond or on how to ventilate in the best possible manner according to each situation. Hereafter, while constantly examining the need for disinfection, we are going to keep responding to the situations as a consultation desk.
Guidance using a video projection screen before the tour of the mural painting conservation facility
During the seven days between January 18th and January 24th, 2020, the mural paintings conservation room of the Takamatsuzuka Tumulus was opened to the public.
Beginning in 2008, this was the 28th time the mural paintings were opened to the public. During this period, four researchers from Tokyo National Research Institute for Cultural Properties (TNRICP) worked as staff.
In this exhibition, the black tortoise drawn on the north wall, the northern divine creature that symbolizes “winter,” the female figures painted on the west and east wall, and the male figures drawn on the west and east wall were placed to the side of the walkway for visitors. Many visitors have confirmed the current state of all mural paintings.
In recent years, the difference in the condition of the murals post cleaning became increasingly evident and many visitors were amazed by the difference between the mural paintings and the photos of them displayed on the wall in the conservation room. Additionally, there were those who compared the drawn black tortoise to that in the Kitora tumulus mural paintings exhibition, which was held at the same time at the Center for Preservation of Kitora Tumulus Mural Paintings.
A series of projects related to mural paintings of the Takamatsuzuka Tumulus are being conducted by the Agency for Cultural Affairs under the overarching project entitled “Research in relation to permanent preservation measures of the National Treasure Takamatsuzuka Tumulus.” In addition, the TNRICP has been centrally involved in the work for many years. The murals paintings have been taken out of the mound alongside the stone material from the mounds in 2007. After that, the conservation treatment of the painting or plain surfaces contaminated with mold and biofilm occurs and plaster with advanced porosity is consolidated and stabilized at the temporary conservation facility near the tombs. In this 12th year since the start of the conservation project, it will reach a break once. Research of conservation and utilization of the mural paintings will have continued by the time it exhibits in a new museum.
As cultural properties attract more attention, conservation and restoration measures have been required for works comprised of various materials in recent years. Under the circumstances, conventional measures are inapplicable in many cases. It is of particular importance that we clean the works without diminishing their value.
To meet these growing needs, the Center for Conservation Science invited Dr. Paolo CREMONESI, conservation scientist from Italy, to organize a workshop on basic scientific knowledge of cleaning and usage of gels from October 8th through 10th, 2019. On October 11th, a seminar on restoration measures for cultural properties was also held to raise on-site issues and introduce the latest research on cleaning of Japanese and Western cultural properties.
With regard to the workshop, lectures were delivered in the seminar room in the morning (to 56 participants). During the afternoon training in the conference room, 21 trainees learned how to prepare cleaning solutions used for the restoration of cultural properties and how to actually clean them.
At the seminar, Dr. Cremonesi delivered a lecture on “Cleaning Methods in Western Countries –Application of Gels and the Latest Cases,” in addition to “Cleaning of Oriental Paintings” by Ms. YAMAMOTO Noriko, Representative Director of the Association for Conservation of National Treasures, and “Potentiality of Gels Applicable to Paper and Photo Works” by Ms. SHIRAIWA Yoko, photo restorer. They introduced the current state of restoration sites in the East and the West. TORIUMI Hidemi and HAYAKAWA Noriko from the Center for Conservation Science gave lectures on the “Historical Background of Cleaning Methods Developed for Western Paintings” and the “Development of Cleaning Solutions for Cultural Properties – Introduction of Recent Studies,” respectively.
The abovementioned training was held from July 8th to 19th, 2019. After receiving more than double the amount of applications than the number of places available this year, we managed to provide training for 31 curators and museum officials.
This year’s training was the first one which was implemented jointly with the National Center for the Promotion of Cultural Properties (CPCP). The CPCP took charge of the training sessions in the first week and Tokyo National Research Institute for Cultural Properties (TNRICP) in the second week, with the lecture programs being completely altered. During the first week, participants learned about the basics of the conservation environment through classroom lectures and practical workshops, while the CPCP shared useful information on social media. With the training this year being jointly held, it became clear that we lacked the ability to deliver the information adequately.
During the second week, certain sections at the Center for Conservation Science provided separate half-day sessions respectively, and provided classroom lectures and other programs under the following topics: scientific study on cultural properties (Analytical Science Section); measures to prevent biodeterioration damage (Biological Science Section); conservation of outdoor cultural properties (Restoration Planning Section); thermal environment control (Preventive Conservation Section); and types and attributes of restoration materials/conservation and restoration of paper artworks/cultural properties of Japanese painting (Restoration Materials Science Section). These programs dealt with a wide range of issues, including methods to apply concepts and basic knowledge of restoration in relation to actual issues and a workshop to learn how to use TNRICP’s latest technologies and achievements for on-site work. Participants appreciated these sessions, commenting that they were very helpful.
In 2020, we believe that it will be quite difficult to hold the training in July due to the Tokyo Olympics and Paralympics and other relevant events. In order to prevent any inconvenience for participants, we will let you know about the schedule for the next planned training immediately after it is decided.
Preparing to measure ventilation volume
From 2017, Rikuzentakata City have entrusted Tokyo National Research Institute for Cultural Properties with inspecting and improving the storage environment of cultural assets at the City Museum that were damaged by a natural disaster. Based on our inspections, we were consulted on issues and countermeasures relating to atmospheric pollution and indoor air pollution affecting cultural assets and the human body, proposals to improve on the management of cultural assets, and proper methods to care for damaged materials.
The first on-site inspection of 2019 fiscal year was performed on June 27th and 28th, 2019. The Rikuzentakata City Museum stored the damaged cultural assets in an elementary school building by making requisite modifications. This year, efforts are focused on the ventilation of a classroom used as a storage room. We hope to be of assistance in this project while cooperating with the several groups involved in the restoration of the damaged materials.
A scene from the workshop
The 2nd workshop for specialists on the new insecticidal treatment for historical wooden buildings, known as “humidity-controlled warm-air treatment,” was held on May 9th, 2019.
Pest-borne damage to historical wooden buildings risks not only the loss of important wooden materials but also building safety, as the wooden materials can become hollow, thus weakening the strength of the lumber construction material and the building itself. In response to severe pest-borne damage, the Rinno-Ji Temple at Nikko has undergone closure and repair. Fumigation with sulfuryl fluoride gas, which is known to have almost no effect on cultural properties, was performed to eradicate all noxious pests in the building. However, there are huge health and safety risks associated with the use of mass fumigation with poisonous chemical substances, and such treatment can also dissuade neighboring institutions from opening to the public.
To address this issue, humidity-controlled warm-air treatment was developed as a new insecticidal treatment. This method eliminates pests by increasing the temperature to 60 degrees Celsius while regulating the humidity without altering the water content of the wood, thus minimizing any damage to the wooden content. Two successful domestic cases have been reported with no significant damage found in buildings containing Urushi (Japanese lacquer) decorations. Subsequent examination of these cases indicates that the technology used in this new treatment is nearly ideal. Nevertheless, concerns have been raised regarding the number of technicians required and the cost involved, which must be addressed before formally establishing humidity-controlled warm-air treatment as a valid insecticidal treatment. Also, since this a newly developed treatment, its long-term performance is difficult to evaluate; there may be as yet unknown effects inherent in the use of this treatment.
Several issues must be resolved before humidity-controlled warm-air treatment can be considered to be an established insecticidal treatment method. We look forward to working over the long-term in cooperation with related organizations.
Many museums frequently ask for our advice on how to reduce the concentration of ammonia and acetic acid kept inside their repositories and exhibition cases. Ammonia accelerates discoloration of oil paintings, while acetic acid badly erodes metallic goods, especially artifacts and coins containing lead. This work is indispensable for preserving cultural assets.
This guide, edited by the Preventive Conservation Section, is the fruit of research on display environment for preservation and utilization. You can read it from April 2019 in the notice exhibited on the first page of Center for Conservation Science on the website of Tokyo National Research Institute for Cultural Properties (in Japanese). We have intended to provide content covering the basic knowledge of air cleaning, monitoring pollutions, and their countermeasures so that all kinds of people can use the guide, including curators, workers entrusted with controlling air conditioning, and researchers. The end of the guide presents “frequently asked questions” with an easy access to the pages referred to in the answers. The appendix explains concrete processes of measuring methods using many pictures. We have also provided reference books and documents for those who want to know more details.
It will be our pleasure if this can help improve the environment of museums.
Ongoing general discussion
In recent years, cultural properties have been attracting more attention. In response to their promoted utilization, the number of cultural properties that need restoration has been increasing. Under the circumstances, conventional restoration approaches and concepts are not applicable in many cases. In the light of the current situation, the “Seminar on the Current Status of Restoration of Cultural Properties and Its Issues” took place on November 22nd, 2018. Sharing a restoration overview of the past, experts specializing in cultural property areas introduced the issues identified during the current restoration process.
Guest Professor Toshikazu SASAKI from Hokkaido University, who specializes in historical materials, delivered a lecture on the conservation of historical materials and issues of conservation of folk materials under the title of “Thoughts on Restoration of Arts and Crafts” based on his vast experience accumulated in the Tokyo National Museum, the Agency for Cultural Affairs, and the National Museum of Ethnology. Senior Specialist Tomohiko JINUSHI from the Agency for Cultural Affairs reported “Achievements and Issues in Recent Restoration of Historical Materials” including detailed cases under the existing conditions. Curator Hitomi KITAMURA from the National Museum of Modern Art, Tokyo presented the details of recent restoration of the collection and the issues in that process under the title of the “Current Status of Restoration of Cultural Properties and Recent Issues -With a Focus on ‘Twelve Hawks’-.” Chief Noriyuki NAKANO from the Kyoto Prefectural Government reported what kinds of discussions are actually conducted in restoration and how necessary decision-making should be done. During the general discussion, the audience asked many questions, which resulted in an active Q&A session. The seminar attracted 104 people, who expressed expectations for our continually providing an opportunity to exchange information on the restoration of cultural properties on a large scale through a post-seminar questionnaire survey. The details of this seminar will be published as a report next year.
Gallery exhibition
The Center for Conservation Science has been developing materials required for the restoration of cultural property. One of the items subject to our research is glue. Glue, an animal collagen hydrolysate, has been used as an adhesive since ancient times. According to the information found, the kinds of animals used for producing glue vary and different measures have been used to find better ways to manufacture it. On the other hand, it has not been scientifically defined whether the raw materials and manufacturing methods have any effect on the properties of glue. In recent years, research on the raw materials of glue and its manufacturing methods has finally been carried out. Based on these results, the Restoration Materials Section has been conducting research studies on the characteristics of glue as a restoration material.
On the case of the restoration of a famous Japanese-style painting, “Jo-no-mai (Noh Dance Prelude,” designated as an Important Cultural Property, the suitable glue was selected based on the outcomes of the studies. It is notable that by using glue which keeps whiteness of shell chalk, restoration, which minimizes the possibility of changes in original works, was implemented.
These outcomes were displayed in the Chinretsukan Gallery of The University Art Museum, Tokyo University of the Arts for the Exhibition “Animal Glue and Conservation – To Keep ≪Jo-no-mai≫ -.” The exhibition was co-organized with the Conservation Science Laboratory, Graduate School of Conservation, Tokyo University of the Arts from October 14th to 19th, 2018. In cooperation with Nikawa Labs as one of the organizers, the exhibition displayed the actual glue used for restoration, scientific data, and numerous images including enlarged ones taken during the restoration process. In addition, a visiting researcher, Kentaro UDAKA, delivered gallery talks. This exhibition provided a valuable opportunity for visitors to gain a broad understanding of the relations between research outcomes and the workplace for the restoration of cultural properties.
“Humidity-controlled high-temperature treatment for the bell tower of Chuzen-ji Temple in Nikko (branch temple of Rinno-ji Temple) and on-site inspection”
On September 10th, 2018, we visited Chuzen-ji Temple to inspect the “Humidity-controlled warm air treatment ” for its bell tower. This treatment method aims to expel noxious insects harming pillars and beams of wooden structures under a high temperature (around 60°C). Usually, as the temperature increases, wooden building materials crack or strain. However, it is possible to increase the temperature inside the wood almost without affecting its physical property, since the temperature rises while the humidity in the treated space is controlled with the wood water content maintained at a certain level. The conventional yet sole insecticidal method for historical wooden structures is fumigation treatment, where a structure sealed with covering is filled with vaporized pesticide to exterminate noxious insects inside the wood. However, vaporized gas also affects human health, thus, requiring safety measures against greater risks. Accordingly, it was hard to implement such large-scale treatment for wooden structures continually. This Humidity-controlled warm air treatment is expected as a new approach to overcome such a challenge.
So far, a research team comprising the Association for the Preservation of the Nikko World Heritage Site Shrines and Temples, Kyoto University, Kyushu National Museum, Total System Laboratory Co., the Japanese Association for Conservation of Architectural Monuments, National Museum of Ethnology, Natural History Museum and Institute, Chiba, and Tokyo National Research Institute for Cultural Properties has been proceeding with the studies from basic research for application to old wooden buildings to establishment of application technique. In the basic research, we verified the humidity distribution in the treated space during the test with a chamber, as well as the temperature distribution inside the wood, measured surface strain, and effects on wooden materials. Then, following the treatment testing with a model structure by using a pilot unit manufactured to control the temperature and humidity of actual structures, we finally realized on-site treatment testing of a historical wooden structure for the second time in Japan after Aizendo Hall of Chuzen-ji Temple. We would like to move ahead with this research toward the dissemination as one of new insecticidal methods while organizing these two treatment test results obtained from two buildings of Chuzen-ji Temple.
Discussion during IIC 2018 Turin Congress
The congress of the International Institute for Conservation of Historic and Artistic Works (IIC) was held from September 10th to 14th in Turin, Italy. From Tokyo National Research Institute for Cultural Properties, Dr. Masahide INUZUKA of the Center for Conservation Science participated in the congress.
The theme of this congress was “preventive conservation.” Therefore, as well as the specific topics about conservation environments, material analyses and restoration, the importance of preventive conservation, leadership required for experts, public engagement and other relevant subjects were discussed.
In the session about preventive conservation for historic sites, Dr. Inuzuka made a presentation on the condensation problems and their preventive measures in a conservation facility for a decorated tumulus in Japan. In the poster sessions, the history of the environmental inspection of museums conducted by the Preventive Conservation Section was reported and information was exchanged with attendants from other countries.
The lecture about solvents using molecular models
Practical work of removing stains on a painting
To conserve Japanese paintings, calligraphic works and other pictorial artifacts, we are now increasingly required to have some knowledge of conservation science. To meet these demands of conservators Tokyo National Research Institute for Cultural Properties and the Association for Conservation of National Treasures (ACNT) jointly conducted a workshop with a training program for conservators from July 31st to August 1st, 2018, which included lectures on basic knowledge and practical work sessions. The workshop aimed to provide hands-on knowledge that can be applied to actual conservation works. To achieve this purpose, we designed a curriculum that would help participants accurately understand the chemical properties of organic solvents and enzymes as well as the proper handling of basic laboratory instruments and chemicals for more effective and safer restorations. The workshop has been held once a year since 2016.
A total of 11 people, one from each corporate member of ACNT, participated in the workshop. Dr. Sano, Director of the Center for Conservation Science; Dr. Sato, Head of the Biological Science Section; and I provided lectures on the safe handling of organic solvents; integrated pest management (IPM) for cultural properties at restoration studios; and removal methods of adhesives and stains, respectively. Based on these lectures particularly using models of the molecular construction of solvents, the participants practiced removing various types of stains on the sheets of paper that we prepared, by using suitable solvents and enzymes. The practical work session also covered other topics such as the use of cyclododecane as a temporary protective coating for water-sensitive colorants. Mr. Kimishima, ACNT’s Senior Conservator, taught in the work session and provided hands-on training to the participants.
The program ended with a lively Q&A session and discussion. We will continue to hold such workshop in the future.
The symposium in session
On-site survey: Steam hammer Taipei Factory No. 141 still remains at the smithery in the vehicle factory of Taipei railway workshop (manufactured by Toyo Iron Works and purchased in 1934).
The Modern Cultural Heritage Section has been interacting with Taiwanese officials and researchers working on cultural properties since FY 2017 so as to share mutual experiences and issues on conservation and utilization of modern cultural heritage for their smooth resolution through research.
As part of this activity, we participated in the “International Symposium on the Conservation of Modernization Heritage and Its Promotional Planning” held under the auspices of the Bureau of Cultural Heritage, the Ministry of Culture and Chung Yuan Christian University in Taiwan on August 17th, 2018. At the symposium, Japanese experts representing the industrial heritage, railway and machinery areas delivered lectures. Mr. Kitagawa, the Head of the Modern Cultural Heritage Section at Tokyo National Research Institute for Cultural Properties, lectured on the administration of cultural properties related to modernization heritage. The symposium attracted a large Taiwanese audience, including administrative officials, owners of cultural properties, university researchers, and citizen groups, resulting in engaging discussions ranging from the principles of conservation and utilization of modernization heritage to their approaches.
In conjunction with the symposium, we discussed with Taiwanese researchers how hydraulic structures, factories, and railway facilities constructed during the period of Japanese rule have been conserved and utilized, along with various approaches and issues. Among them was a very interesting case in which a motorcycle manufacturer who had developed an electric-assist railbike made use of the dead track of a now-defunct railway. The railway is now protected as a cultural property for the operation of the facility.
We also visited Director-general Gwo-Long Shy and other officials at the Bureau of Cultural Heritage, the Ministry of Culture in Taichung. There, we exchanged ideas on Japanese and Taiwanese histories, and on concepts concerning systems for the protection of cultural properties associated with modernization heritage, as well as their conservation and utilization.
Ongoing symposium
Jet engine components displayed in the venue
The Institute of Asian Cultural Studies and the Peace Research Institute of International Christian University, and Tokyo National Research Institute for Cultural Properties held a symposium titled “Towards a History of “HERE”: Learning from the Phantom Jet Engine” at the University on June 2nd, 2018. This symposium focused on looking back at the history of International Christian University (hereafter called “ICU”) founded on the premises of the research institute of the Nakajima Aircraft Company, which developed three jet engine components discovered on the campus in 2015, while widely sharing their values as cultural properties.
For the first half of the symposium, Mr. Masahisa TAKAYANAGI, a teacher at ICU High School, talked about how the components were discovered, and their significance. Then, Mr. Hiroyuki NAGASHIMA, former visiting researcher at this Institute, introduced the outcomes of the survey on cultural properties conducted jointly by Tokyo National Research Institute for Cultural Properties and the Japan Aeronautic Association in 2017; and Mr. Shigeyoshi KANDA, a visiting researcher at this Institute, presented reference information contributing to their publication and utilization in the future. For the last half of the symposium, following the screening of a video work produced by students, Mr. Hikaru OKUIZUMI, a writer, Dr. Yoko KATO, a professor at the University of Tokyo, and Dr. Masakatsu OKADO, a professor at Yokohama National University, gave their perspectives from their own points of view in a bid to evoke speculation about the jet engines, and the histories of the Tama area and World War II. At the end of the symposium, a comprehensive discussion was created based on questions from the audience.
ICU is expected to continually consider conservation and utilization approaches that are unique to education and research institutions by clarifying the histories of the university and the surrounding area and using cultural properties to convey their values to many people while reviewing the issues presented by them.
Scene of the private view
Scene of the exhibition
It is seven years since the 2011 Tōhoku earthquake and tsunami. We offer our sincere condolences on the death of victims of the unprecedented tragedy, and we express our gratitude to those who have worked in restoration assistance following the disaster. Iwate Prefectural Museum, where thousands of cultural assets that were damaged by tsunami have been treated for stabilization treatment, held panoptic exhibitions from March to May, which demonstrated to us the importance of conservation of tsunami-damaged assets. During these exhibitions, we exchanged information with specialists involved in stabilization work of damaged assets.
Two exhibitions, “Asu ni tsunagu Kesen no takaramono–Tsunami de hisai shita Rikuzentakata shiryo wo chushin ni (The treasures of Kesen that we pass on to the future generations –with a focus on tsunami-damaged assets in Rikuzentakata)” (March 3rd to 28th, 2018) and “Mirai heno yakusoku–ima katari hajimeta Kesen no takaramono” (A promise to the future–the treasures of Kesen that start to talk now)” (April 3rd to May 6th, 2018), introduced the damaged cultural assets that stabilization treatment of which was finished. During the opening ceremony, the deputy director general of our institution, Eriko Yamanashi, gave a congratulatory speech by guests, instead of the director general, Nobuo Kamei, who could not come to the museum. In the private view, the director of Center for Conservation Science, Chie Sano, gave an explanation of our study on the stabilization processing of tsunami-damaged documents. It seemed that the exhibitions were strongly motivated activities. There were descriptions of every asset’s condition before stabilization, and stabilization methods used, as well as the cultural assets that stabilization treatment of which was finished.
Through seven years of the work, stabilization treatment of 220,000 items, out of 460,000 damaged items, has been completed. However, 240,000 cultural assets are still awaiting stabilization in the museum. The number of tsunami-damaged assets is enormous. In addition, the assets have many types of problems such as unpleasant odor. We would like to contribute to the conservation of damaged cultural assets through scientific study.
Complete view of the Hien. The national marking (red sun) on the surface of the right-hand main wing is reproduced with projected red light.
The national marking (red sun) on the right-hand side of the fuselage is reproduced every two minutes by projection mapping.
Visible are two traces of the national markings (red sun) on the left-hand side of the fuselage. The larger one is a trace of one painted after the war.
The trace of the airframe number “6117” below the supercharger air intake.
The Kawasaki Ki-61-II Hien (flying swallow), possessed by the Japan Aeronautic Association, was manufactured at the Gifu Works of Kawasaki Aircraft Co., Ltd. in 1944. When World War II ended in 1945, it belonged to the Air Evaluation Department of the Imperial Japanese Army located at the Fussa Air Base in Tokyo. Although almost all Japanese aircraft were scrapped after the war, this fighter was not disposed of for some unknown reason and had been displayed at the US Yokota Air Base until 1953. This Hien is now the world’s only airframe displayed in a museum. (There have been several attempts to restore the Hien, using the wreckage retrieved from New Guinea.) This fighter was transferred to The Japan Aeronautic Association from the US forces for free in 1953. Until 1986, when it was exhibited in the Chiran Peace Museum (Minamikyushu City), the fighter was displayed all over Japan. Meanwhile, some of its parts were lost and the airframe was damaged. When necessary, temporary repairs were carried out while painting and marking distinctly different from the original ones were applied from 1965 onwards.
In recent years, the Japan Aeronautic Association has begun to recognize anew the Hien as a cultural property through joint research with the Center for Conservation Science. Kawasaki Heavy Industries, Ltd. (hereinafter KHI) offered full cooperation in restoration of the Hien as a commemorative project to celebrate the 120th anniversary of its foundation in 2016. In 2015, the fighter was restored at its Gifu Works for almost a year.
Prior to its restoration, it was decided that the Hien would be restored as a cultural property through negotiation between the Japan Aeronautic Association and KHI. As for individual items for restoration, KHI proposed restoration methods, which the Association checked and accepted. The restoration by KHI covered a wide range of issues, including the removal of the paint applied on the airframe surface, removal of non-original parts added after the war, and production of new replica parts such as the nose panel above the engine and the instrument panels of the cockpit.
Removal of the paint on the airframe surface revealed the traces of the drilling tool blade that slid over the skin of the wings during manufacture, as well as traces of national markings and caution notes on various parts of the airframe. It also revealed the fact that the airframe number (construction number) was “6117.” Repainting of the national markings, which was proposed by KHI, was not implemented due to a possibility that new paint might affect the airframe surface and for the value of exhibiting the discovered traces as they are. When the Hien was exhibited at Kobe Port Terminal Hall (Kobe City) for about one month in autumn 2016, the national markings were reproduced with wrapping film at the request of KHI. The film was peeled off after being delivered to the Kakamigahara Aerospace Science Museum (Kakamigahara City). Although the museum had been closed since September 2016 for renovation, the disassembled Hien was displayed in the repository from November 2016 through November 2017.
After the restoration by KHI, the Japan Aeronautic Association surveyed the Hien under the supervision of the Center. This led to the removal of deteriorated rubber parts and the replacement of the fabric on the control surfaces (the rudder, the elevators, and the ailerons). Like many other aircraft of that time, the control surfaces are composed of a metal framework covered with fabric. When the fabric was replaced in 1986, it was not sewed to ribs, which resulted in creating a different appearance. Therefore, the Center researched the material of the fabric used in the WW2 era so as to provide supporting data for replacement of the fabric. This replacement was carried out from autumn 2017 through February 2018. The Center also took photos of the airframe before and after the reassembly for the record.
When the Museum was reopened after the renewal as “Gifu-Kakamigahara Air and Space Museum” on March 24th, 2018, the Hien became one of the main exhibits there. According to the Museum, many visitors positively accept the unpainted national markings, and this fact indicates that the perception of aircraft as cultural property is spreading in our society.
Registration booth for the public exhibition of the conservation facility for mural paintings of Takamatsuzuka Tumulus, a national treasure
I participated as a staff explained in the public exhibition of the conservation facility for the mural paintings of Takamatsuzuka Tumulus, which are designated as a national treasure. After the dismantling of the stone chamber from Takamatsuzuka Tumulus in 2007, the conservation facility was opened to the public twice a year. From 2017 onward, the frequency of public exhibitions of the facility, along with the mural paintings of Kitora Tumulus at Shijin no Yakata, the Kitora Tumulus Mural Experiential Museum, was increased to four times a year. Tokyo National Research Institute for Cultural Properties has been hosting these events since the first time the facility was opened to the public.
At the 20th public exhibition held recently, we placed the West Wall (Group of Female Figures, White Tiger, and Group of Male Figures) and the North Wall (Black Tortoise) in the area close to the exhibition corridor to provide visitors a view of the progress of the conservation of the mural paintings since they were taken out from the tumulus ten years ago; moreover, visitors can compare the paintings with the mural painting of Black Tortoise from Kitora Tumulus, which was also on exhibition at the same time. Although the event was held during winter, when the number of tourists to Asuka Village is low, it attracted approximately 1,000 visitors, including people without pre-registration. Many visitors were amazed with the progress of the cleaning of the mural paintings, and left with newly developed interests in the future restoration process and exhibitions.
Visit to a lacquerware production site in Myanmar
The Tokyo National Research Institute for Cultural Properties conserves and restores cultural properties, as well as conducts research and study in collaboration with educational/research institutes, private and other organizations, not only at home but also abroad. As one of these activities, the Institute reached an agreement on the protection of lacquer work cultural heritage in Myanmar with the Small-Scale Industries Department of the Ministry of Co-operatives, Myanmar in 2014 while organizing a workshop on lacquerware at Bagan Lacquerware Technology College in 2016. Even after the expiration of the agreement, another workshop was held at the College in February 2017, where lacquerware was practically observed and lectures on conservation/restoration cases and scientific analyses were given, maintaining the cooperative relationship.
On December 7th, 2017, we visited the College to decide on the policies for future cooperative programs by exchanging opinions. Its main topics were the safety and features of lacquerware sold in the Bagan area from a scientific perspective, and both parties agreed that mutual understanding should be promoted further. In addition, we visited lacquerware production sites in Myanmar for future cooperation on December 7yh and 8th, promoting a better understanding of Myanmar’s lacquerware.
Two exhaust nozzles of a jet engine carried into the laboratory. The right part has a cover
Process of separating the cover
The Center for Conservation Science, under the request of International Christian University, together with Japan Aeronautic Association, conducted survey of two materials which were excavated on the university campus in 1950 and were most likely to be parts of a jet engine. A survey conducted at the university on May 20th, 2017 revealed that they were likely to be exhaust nozzles of a jet engine manufactured in Japan during World War II. In response to this result, a more detailed investigation was conducted at the Center’s laboratory from July 6th to October 26th.
In addition to survey of the literature and visual inspection, measurement of major dimensions and weight and survey of the structure material were carried out, together with photographic recording. Furthermore, X-ray CT photography was conducted with the cooperation of the Tokyo National Museum for the purpose of investigating the composition of the material and the internal structure. One of the two surveyed materials consisted of two parts. After being carried into the Center, it was carefully separated, foreign matters such as dust and dead leaves adhering to the surface were removed, and anticorrosive treatment was provided.
Through the investigation, it has been confirmed that there are engravings similar to those engraved on other Japanese aircrafts manufactured during the wartime, all parts are made of stainless steel and therefore heat resistant, and the shape and structure are similar to the exhaust nozzles of jet engines “ネ130” and “ネ330,” which were also developed in Japan during the wartime. As a result, it is concluded that the materials are highly likely to be exhaust nozzles of a jet engine made in Japan and that the corresponding engine is “ネ230,” developed together with Hitachi by Nakajima Aircraft Company, which existed during World War II on the grounds of International Christian University. The exhaust nozzles are considered to have been never used because of the absence of any traces that they were attached to the body of a jet engine using bolts.
Out of the jet engines developed in Japan during the wartime, only two examples of parts have been confirmed to exist. Therefore, the materials surveyed this time are quite valuable, showing both the advancement of Japanese technology in the 1940s and the process of the aircraft development in Japan.
On October 26th, the representatives of the survey team visited International Christian University and submitted an interim report to President Junko Hibiya. In the future, the final report will be compiled including results of the survey on the value as cultural property.
Fig.1 An interview on site
Fig.2 The freeze-drying equipment for tsunami-damaged documents
Natural disasters, such as earthquakes and typhoons, are causing serious damage to cultural property. The National Institute for Cultural Heritage has conducted interviews with museums and prefectural offices regarding the risk management of cultural property all over Japan in order to build networks providing for disasters, because it is necessary to protect our cultural heritage and pass it on to future generations. We are in charge of Hokkaido and Tohoku areas, and conducted an interview with Tohoku University of Art and Design on September 15.
In the university, documents that were damaged by the Great East Japan Earthquake have been subjected to a freeze-drying process in order to dry them. We obtained information giving a detailed description of the time of the disaster in 2011. In addition, we learned about some problems and tasks on site.
Through these interviews, we found that there were many types of risk management for cultural property in each region. We will continue to conduct interviews, and aim to build Cultural Heritage Disaster Risk Mitigation Networks that help people and protect our cultural property when problems arise.
