Investigation and Research on the Conservation of the Plaster Remaining in Stone Chambers and Sarcophagus in Tumuli

Plaster remaining in the stone sarcophagus

　The Tokyo National Research Institute for Cultural Properties (TOBUNKEN) visited the Oichi No.1 Kofun (tumulus) in Fukuyama City, Hiroshima Prefecture and investigated the conservation status of the plaster remaining in the stone sarcophagus, in cooperation with the Culture Development Section, Economic Environment Division of Fukuyama City, on October 20th, 2022. Plaster, a type of construction material used for tumulus construction, requires specific knowledge and techniques regarding all processes from manufacturing to application. Therefore, it is a precious archaeological material which shows how technology was transferred when those tumuli were constructed. Hence, regardless of the coloring and/or decorations on it, plaster conservation is considered important and implemented in many cases outside Japan. Though there are more than 40 tumuli where plaster usage is confirmed in Japan, they are not widely known like Takamatsuzuka and Kitora Tumuli. While most of these tumuli were designated as cultural properties, plaster conservation measures are rarely taken up; the plaster is left to erode due to weathering and flaking every day.

　The Oichi No.1 Kofun keeps the highest percentage of plaster in Japan. We wonder why it is not designated as a cultural property. Furthermore, it does not just keep the plaster, but we can even identify plaster application traces, which were considered to be made when the plaster was applied during the tumulus construction in the area, where the conservation status is good enough. It can be a precious clue to identify the tools used during the construction. In this investigation we discussed sustainable measures for plaster conservation based on the confirmation of its conservation status and environment, by considering the sense of morality on the cultural property conservation and restoration including material adaptability and aesthetic appearance.

　Utilization of the cultural properties is required now more than ever. It is time to revise the methods of passing down the cultural properties to future generations in the given situation. The plaster remaining in tumuli is one of these cultural properties. We will discuss further the appropriate measures for conservation and methods to maintain and manage it for its future utilization by revising the current situation where the plaster has been decaying and lost, while also referring to the similar advanced cases in and outside Japan.

Inking Ceremony for the Replica of the Kuju Landslide Disaster Cenotaph

Inking ceremony at Shingu City Hall (Photo 1)

Replicated cenotaph (Photo 2)

　The inking ceremony for the replica of the landslide disaster cenotaph in Kuju was held at Shingu City Hall on December 5th, 2020. The Kuju district of Shingu City is one of the affected areas of the rainstorm that the Kii Peninsula experienced in 2011. The district houses the stone monument built in remembrance of the tragedy of similar disasters seen in this area in the Edo Period. The Kuju Landslide Disaster cenotaph built in 1821 would get covered with overgrown shrubs, and its muddied surface made it difficult to read the inscription on it. Tokyo National Research Institute for Cultural Properties, therefore, precisely measured this cenotaph, and created a replica using 3D printing technology so that the unreadable characters of the inscription would be readable. As part of the citizen-awareness project for disaster preparedness, an event for this 3D printed replica was held at Shingu City Hall. The head of the Kuju district, the superintendent of education in Shingu City, the researchers involved in printing the replica, and the citizens took turns inking the engraved colorless characters of the replicated cenotaph (Photo 1) until they were readable even to the untrained eye, and suitable for being open to the public (Photo 2). Through this event, we could help people in the community recall the landslides that had occurred in the Edo Period, and contribute to increasing community disaster awareness.

Visit to Earthquake Remains Conserved in Taiwan

Damaged Guangfu Junior High School exhibited in the 921 Earthquake Museum of Taiwan

Projection mapping focused on the fault exposure in the Chelungpu Fault Preservation Park

　A fault exposed in a paddy field due to the 2016 Kumamoto Earthquakes attracted much attention, calling for the necessity of its preservation (as a result, it is designated as a natural monument by Mashiki Town today). As a good example of disclosing and utilizing such preserved fault exposure, the Nojima Fault Preservation Museum (where the fault exposed due to the Hyogoken-Nanbu Earthquake, which triggered the Great Hanshin-Awaji Earthquake, is preserved) established in 1998 is well-known in Japan. In 1999, the Jiji Earthquake occurred in Taiwan. We visited a museum constructed following the Nojima Fault Preservation Museum with further development near Taichung, the damage of which was specifically serious. The 921 Earthquake Museum of Taiwan works well as a disaster prevention museum, which shows earthquakes with a focus on the effectiveness of quake resistance and quake-freeness by conserving a damaged junior high school building with a shelter constructed as the exterior walls of the museum for disclosure. On the other hand, the Chelungpu Fault Preservation Park is a scientific museum, where an exposed fault section confirmed during the survey is directly exhibited inside the housing. The museum also shows the mechanism of an earthquake and the history of past quakes. Particularly, by means of project mapping focusing on the fault surface, they visually show the history of complicated strata in sequence, which is difficult to understand from the current plane of stratification. Application of such an approach is expected in various fields also in Japan, including explanations about remains at archeological sites besides the exhibition of the strata.

“Joint Research between Japan and Korea—Research on the Effect of Environmental Pollution on Cultural Properties and Development of Conservation Techniques” Research Results Presentation Session in FY2015

Joint research regarding the structural reinforcement of stone pagodas (Seven-storey stone pagoda at Myodo-ji Temple)

　Following the concluding of a memorandum of understanding (MoU) between the Center for Conservation Science and Restoration Techniques and the Conservation Science Division, National Research Institute of Cultural Heritage, Republic of Korea, the two organizations have been collaborating on “Joint Research between Japan and Korea—Research on the Effect of Environmental Pollution on Cultural Properties and Development of Conservation Techniques.” More specifically, they have been undertaking joint field studies of cultural properties made of stone in outdoor locations in both countries, and have been holding annual research results presentation sessions, with the venue alternating between Japan and Korea, with the aim of sharing the research results achieved in each country.
　This year’s research results presentation was held in Japan on July 8, 2015, in the Basement Level Meeting Room of the National Research Institute for Cultural Properties, Tokyo. The theme for the presentation was issues relating to the structure of stone-built cultural properties. The Japanese and Korean researchers reported on and discussed their respective research results. In addition, taking advantage of the Korean researchers’ visit to Japan for the presentation, a study visit was arranged to examine the nine-storey stone pagoda and seven-storey stone pagoda, etc. at the Myodo-ji Temple in Yunoma Town, Kumamoto Prefecture (where the Japan-based joint field studies have been undertaken), and to exchange information regarding new developments in structural reinforcement methods.

Joint research between Japan and Korea: The effects of environmental pollution on cultural properties and R & D of conservation techniques, 2014 Conference

2014 Conference (National Research Institute of Cultural Heritage, Republic of Korea)

　The Center for Conservation Science and Restoration Techniques concluded a memorandum of understanding with the Conservation Science Division of the National Research Institute of Cultural Heritage of the Republic of Korea. Both institutes are proceeding with “Joint research on the effects of environmental pollution on cultural properties and R & D of conservation techniques.” Specifically, both institutes are conducting joint field studies of outdoor stone heritage in both countries and they are both hosting an annual conference. Researchers from both institutes are endeavoring to share their results with their counterparts.
　National Research Institute of Cultural Heritage, the Republic of Korea is overseeing the research this year, so a conference was held on May 27 in a lecture hall at the Cultural Heritage Conservation Science Center. The conference was attended by OKADA Ken, KUCHITSU Nobuaki, and MORII Masayuki from the Center for Conservation Science and Restoration Techniques. The conference garnered interest, as was evinced by the almost packed venue. At the conference, lead Japanese and Korean researchers and cooperating university professors gave presentations on stone heritage, and an active discussion took place with attendees asking numerous questions and offering numerous comments. Plans are to conduct joint studies of cave tombs in the future.

24^th Conference on International Cooperation on Conservation

General discussions

　The 24^th Conference on International Cooperation on Conservation titled “Thinking of conservation with a protective shelter” was held on July 8, 2010, with 71 participants. Protective shelter are sometimes used to conserve sites. To understand the advantages and disadvantages of protective shelter, it is necessary to know their state after a certain number of years have passed since they were built. For this reason, we asked three persons to make presentations and then we had general discussions. First, Mr. Anat Bamurunwonsa of the Fine Arts Department of Thailand gave a lecture titled “Protective shelter for a pair of Buddha’s footsteps in the Prachinburi Province.” This was followed by Mr. Irisa Tomoichiro of the Cultural Properties Protection Division, Fukuoka Prefecture, who delivered the lecture “Varied forms and current status of protective shelter in Fukuoka.” Then, Ms. Shin Eun-Jeong of the National Research Institute of Cultural Heritage, Korea, gave a lecture titled “Current status and case study in covering roofs for stone cultural properties in Korea.”The lectures and discussions made us recognize, for site conservation, the need to appropriately decide on specifications of protective shelter, after understanding the conditions such as the ambient environment of sites, and the importance of continuously monitoring the built roofs.

23rd Conference on International Cooperation on Conservation

Overall discussions

　The 23rd Conference on International Cooperation on Conservation titled “Why have Sites Remained?” was held on October 8, with 43 participants. When considering site conservation, damaged sections are generally investigated and the cause of the deterioration is studied. At this conference, however, we selected well-conserved sites, examined why they have remained undamaged, and aimed to consider the conservation of damaged sites going forward. Three presentations were made and overall discussions were held: Ms. Paola Virgili from the Rome Cultural Heritage Preservation Bureau, Italy presented “Augustus Pantheon and Hadrian’s Pantheon: Studies, digs, research and diagnosis for future conservation and prevention”, Mr. Harada Masahiro from the Tottori Buried Cultural Property Center presented “Conservation Environment of Aoyakamijichi Site”, and Mr. Cecep Eka Permana from the University of Indonesia presented “Rock art in South Sulawesi, Indonesia”. Conference participants understood the background and scientific conditions for site survival, and shared useful information for future site conservation.

Business Trip to Cambodia

Coating chemicals to remove microorganisms

　We surveyed the deterioration of the stone ruins of the Angkor Wat temple complex in Cambodia July 24 to 28. In the Ta Nei ruins, we used a new sandstone material similar to that used in the ruins and continued to survey the influence of microorganisms on the erosion of the stone by letting microorganisms flourish on the surface of the new material. The section of the stone with abundant lichen was coated with chemicals to try cleaning, and both positive and adverse effects were observed. We collected fundamental data concerning this research and study at the local site and carried out a construction experiment. We also assisted with the experiment in cleaning microorganisms on the surface of stone at the Western Prasat Top, where the National Research Institute for Cultural Properties, Nara did research, and collected data concerning the cleaning.　We surveyed the deterioration of the stone ruins of the Angkor Wat temple complex in Cambodia July 24 to 28. In the Ta Nei ruins, we used a new sandstone material similar to that used in the ruins and continued to survey the influence of microorganisms on the erosion of the stone by letting microorganisms flourish on the surface of the new material. The section of the stone with abundant lichen was coated with chemicals to try cleaning, and both positive and adverse effects were observed. We collected fundamental data concerning this research and study at the local site and carried out a construction experiment. We also assisted with the experiment in cleaning microorganisms on the surface of stone at the Western Prasat Top, where the National Research Institute for Cultural Properties, Nara did research, and collected data concerning the cleaning.

Expert Meeting on Cultural Heritage in Asia and the Pacific

Commemorative photo of the participants

　From January 14-16, 2009, the Expert Meeting on Cultural Heritage in Asia　and the Pacific: “Restoration and Conservation of Immovable Heritage Damaged by Natural Disasters” was held in Thailand. This meeting was jointly sponsored by the National Research Institute for Cultural Properties, Tokyo and Fine Arts Department of the Ministry of Culture, Thailand. It was also supported by SEAMEO-SPAFA (Regional Centre for Archaeology and Fine Arts under the aegis of the Southeast Asian Ministers of Education Organization) and the Embassy of Japan in Thailand. On the first two days, a round-table conference was held at the Siam City Hotel in Bangkok, and on the final day there was an excursion to the sites in Ayutthaya where actual measures against and post-disaster restoration are being implemented. At the round-table conference, one representative each from Indonesia, Malaysia, Myanmar, Philippines, and Vietnam as well as Thailand and Japan made presentations. Observers, including local university personnel, presented their opinions and asked questions, and active discussions were held. During the excursion, various types of information on restoration materials were shared by the participants.

Hosting the 22^nd international workshop on conservation and restoration of cultural properties

Presentation at the 22^nd international workshop on conservation and restoration of cultural properties

　The 22^nd international workshop on conservation and restoration of cultural properties entitled “Conservation of Sites and Water” was held on September 19, 2008, with 75 participants. 3 presentations were made: “The Hydrology, Hydraulics, and Geotechnics of Moenjodaro” by Mr. Richard Hughes of the International Heritage Conservation and Management Ltd., UK; “Present Condition and Problems of Conservation at the Sendai City Tomizawa Site Museum” by Mr. Sato Hiroshi of the Sendai City Tomizawa Site Museum; and “The Underwater Park of Baiae – Preservation and Public Access” by Dr. Nicola Severino of Naples and Pompei Special Archeology Station, Italy. These presentations were followed by comprehensive discussions. Ways to avoid water are often discussed in conserving sites, and exam-ples of sites at which conservation is conducted on the premise that there is water may be useful as reference when considering the conservation of sites in different circumstances.

Hosting the 4^th Debriefing Session of Japan-Thai Joint Research Results

The 4^th Debriefing Session of Japan-Thai Joint Research Results

　Based on the letters exchanged between the Thai Culture Ministry Fine Arts Department and the National Research Institute for Cultural Properties, Tokyo in October 2006, the Japan Center for International Cooperation in Conservation is performing joint research with the Fine Arts Department on the deterioration and conservation of ruins in Thailand. We hosted the debriefing session of the research results in Bangkok.
　The session took place at the Thai National Gallery on September 4 and 5. Research presentations were given at the session – six from Japan and four from Thailand- and lively discussion took place among the approximately 30 local researchers who participated.
　While staying in Thailand, we visited the Fine Arts Department, and had a meeting concerning the Asian Cultural Heritage International Conference to be held on January 14-16, 2009.

On－site investigation in Thailand and Cambodia

Investigation of the properties of sandstone (suscptibility) (Angkor Site, Cambodia)

　In July, the Japan Center for International Cooperation in Conservation conducted investigations of the deterioration of stone sites in Thailand and Cambodia.
　In Thailand, the Center cooperated with the Fine Arts Department of the Ministry of Culture of Thailand to investigate sites in Scothai and Ayutthaya. At Wat Sri Chum in Scothai, we determined the difference in quantity of water evaporation between a place which is suitable for the growth of algae and another which is not. At Wat Mahathat in Ayutthaya, we conducted a follow－up study of conservation work that had been executed in 2004 in order to control weathering by salts, partly to determine how lasting the effect of this work has been.
　In Cambodia, we cooperated with APSARA to investigate the effect of the presence of lichens and bryophytes on the deterioration of stone materials. In particular, we studied the sandstone of Ta Nei to determine the difference in strength and other properties between a place in which microorganisms are present on the surface and another in which they are not.
　During our stay in Bangkok, we visited the Fine Arts Department to discuss matters concerning the Expert Meeting on Cultural Heritage in Asia and the Pacific to be held from January 14 to 16, 2009 in Bangkok.

21^st Conference on International Cooperation on Conservation

A scene from the conference

　21^st Conference on International Cooperation on Conservation: “Monitoring after Conservation Work” was held on December 6, 2007 with an attendance of 93 persons. Three presentations were given: Nishiura Tadateru of Kokushikan University, “Importance of Monitoring for Conservation of Remains, and Its Problems”; Nahar Cahyandaru of Borobudur Heritage Conservation Office in Indonesia, “Monitoring of the Borobudur Post Restoration”; and Kim Sa-Dug of the National Research Institute of Cultural Heritage, Korea, “Long-term Plan for the Conservation of Seokguram Grotto.” The presentations were followed by discussions. Various monitoring methods used ad respective sites were introduced and information was shared among the participants. We were made to realize that in order to introduce these methods to other sites it is necessary to make wider appeals about the importance of monitoring.