|■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
Study on the reinforcement measures for the foundation structure of the East Gate
The ICC Secretariat visited the restoration work site of the East Gate (courtesy of APSARA)
Tokyo National Research Institute for Cultural Properties provides continuous technical support to the Authority for the Protection and Management of Angkor and the Region of Siem Reap (APSARA) for the conservation and sustainable development of the ruins of Ta Nei Temple in Angkor, Cambodia. Last year, the restoration of the East Gate began under the Conservation and Sustainable Development Plan jointly developed by APSARA and the Institute. APSARA is responsible for securing the budget for materials and labors, as well as implementing the work. The Institute provides technical assistance on restoration methodologies and procedures, as well as cooperation in architectural and archaeological surveys before and during the work.
The possibility of our visiting Cambodia has all but disappeared after March this year, due to the global travel bans implemented to fight the COVID-19 pandemic. However, we cannot suspend the restoration work for our convenience, given that COVID-19 has not spread widely in Cambodia and the Cambodian counterpart has been continued regular site duties. From April, we have been benefiting from the advantages of Information & Communication Technology (ICT), actively utilizing interactive networking services with smartphones, besides normal e-mail messaging, to grasp real-time conditions at the site and hold online meetings as needed.
On the 21st of April, an online meeting was conducted with the East Gate restoration team of APSARA to share the result of the foundation’s geological testing during February and March and discuss restoration methods and structural reinforcement measures, based on the test result. Two of our collaborators, Professor KOSHIHARA Mikio (Structural Engineering) and Professor KUWANO Reiko (Geo-technical Engineering) from the Institute of Industrial Science, the University of Tokyo, joined the meeting. After an in-depth discussion from a scientific perspective, the participants finally agreed on a basic scheme for the restoration and reinforcement with an aim to balance heritage authenticity and structural safety. Under this basic scheme, online meetings were held in May and July to study about treating the foundation and superstructure, respectively. We had interactive discussions and shared ideas, plans, and other useful information, as well as the site’s latest condition, and decided that, at this stage, the concrete restoration/reinforcement method be considered the most appropriate one.
The Technical Session of the International Coordinating Committee for the Safeguarding and Development of the Historic Site of Angkor (ICC), organized at APSARA headquarters in June every year, was also postponed, and only the site visit by the ICC co-chairs and the secretariat was done this year. APSARA and the Institute jointly made the progress report and work plan of the project, including the activities mentioned above, and submitted it to the ICC secretariat prior to their site visit. We also held an online meeting with Professor MASUI Masaya of Kyoto University Graduate School, a member of the Ad Hoc Expert Group of the ICC, who supervised and advised us on our recent issues and the project’s work plan and exchanged information about latest information concerning international cooperation on Angkor.
In this way, we accidentally realized a potential of ICT in heritage conservation. Indeed, there is a natural limit to conservation efforts based on telecommunication and remote information sharing because the universal value of cultural heritage is in its object itself. We hope that the world returns to normal, after overcoming the COVID-19 pandemic, and the days of unrestricted international travel are back soon.
Dismantlement of the base platform.
Tokyo National Research Institute for Cultural Properties (TNRICP) has been providing technical support to the Authority for the Protection and Management of Angkor and the Region of Siem Reap (APSARA) for the conservation and sustainable development of Ta Nei Temple in Angkor, Cambodia. As a part of this project, TNRICP dispatched a total of four members, including an outside expert, to Cambodia between February 26 and March 18, 2020 for 3D documentation of the base structure and an investigation of the foundation’s strength of the East Gate under restoration.
Directed by Associate Professor Dr. OISHI Takeshi, from the Institute of Industrial Science, the University of Tokyo, a 3D laser scanning survey was conducted between February 27 and 28, 2020 to accurately record the state of the base platform including that in the excavation pits at the external corners of it, which were revealed after the superstructure was dismantled. After that, it was originally planned to conduct a flat-plate loading test and uniaxial compression test of the laterite substrate material. However, because of the spread of COVID-19, the experts in charge were unable to join the mission and only a simple dynamic cone penetration test (DCPT) was performed at the site, which was also conducted in December 2019.
DCPT was conducted at 11 points to check the bearing capacity of the soil infill inside the platform and the foundation layer at the outer edge of the platform. The outcomes of the test indicated that test points below the wall structure have generally larger values than that of the central area (under the pavement). Although the factors such as the difference in the climatic conditions at the time the tests were performed (wet and dry season) might affect the test results, the long-term structural weight causing the rammed earth beneath the walls to get compacted could have caused this distinction. It could be interpreted as the soil infill inside the platform has developed a certain degree of strength enough to support the upper weight of the structure at present. In addition to DCPT, a core sampling was also conducted with a hand auger to check the cross-sectional structure, including the lowest layer of the foundation.
Further, indoor material tests were performed by Professor Dr. KUWANO Reiko and Assistant Professor Dr. OTSUBO Masahide, from the Institute of Industrial Science, the University of Tokyo. Three kinds of specimens (original laterite stone, new laterite stone used for replacing deteriorated parts, and lime mortar used for the level adjustment) were tested in the laboratory through uniaxial compression test, etc. The test results indicated that there was no significant difference in the strength of the old and new laterite materials.
The recent global pandemic has also affected our international cooperation project severely due to the difficulty of reaching to the site yet still the request of completion of the project as scheduled. However, we are trying to adapt to this situation by trying to find a way to communicate remotely with the counterparts through effective utilization of online meeting tools and the digital data of the structure that we have created thus far.
On-site confirmation before the workshop (overlooking Kabesa village)
Discussions on the workshop (DCHS conference room)
From this Fiscal Year, Tokyo National Research Institute for Cultural Properties (TNRICP) has started an Exchange Project for International Cooperation in Cultural Heritage commissioned by the Agency for Cultural Affairs to provide technical support and capacity building for the preservation and utilization of historic buildings in Bhutan. In 16th January 2020, as part of this project, TNRICP dispatched a team of six experts including three outside experts to participate the Workshop on Conservation of Lham Pelzom house organized by the Division for Conservation of Heritage Sites (DCHS), Department of Culture, Ministry of Home and Culture Affairs.
Lham Pelzom house, located in Kabesa near the capital of Thimphu, is considered to be one of the oldest surviving farmhouses in the country, and is the top candidate for designation as historic farmhouses under Bhutan’s first comprehensive basic law on cultural heritage (New Law) which the government aims to pass. On the other hand, the house has been vacant for a long time, and its deterioration has been remarkable recently. Consequently, the need for preliminary consensus among stakeholders, such as the government, owners and local communities, on the potential for preservation and utilization is growing. Given this awareness, DCHS invited house owners, representatives of local communities, government officials from the Ministry of Work and Human Settlements, and Tourism Council to the workshop, for sharing various views on the conservation of the Lham Pelzom house. TNRICP joined the workshop for giving advice from the theoretical and technical point of view regarding heritage conservation.
In the first half of the workshop, from the standpoint of promoting heritage protection, TNRICP proposed conservation policies and restoration methods based on field research, and DCHS reported on how government support should be provided, including financial aspects. Contrary, from the standpoint of the bearer of actual preservation, house owners strongly requested the need to secure economic benefits through common adaptive use, and local communities emphasized the need for the active involvement of the government in preservation. However, they all understood and welcomed a high reputation as a cultural heritage in general. Subsequently, in the second half of the workshop, meaningful mutual discussions unfolded in the latter half of the workshop, based on opinions, aspirations, and grievances of each participant in the first half. Finally, participants agreed to promote the conservation of Lham Pelzom house as the following conditions.
(1) ACCELERATE procedures for value valuation as cultural heritage, such as designation under the new law,
(2) CLARIFY protection frameworks, including administrative support for restoration works and the house owner’s obligations to the preservation,
(3) CONSIDER a proposal for utilization that is appropriate as a cultural heritage and takes into account the house owner’s demand.
TNRICP will cooperate with DCHS and continue research activities and field surveys to realize the conservation of traditional farmhouses in Bhutan as cultural heritage.
Panel discussion at the third Mayors’ Forum
As part of the above-mentioned project commissioned by the Agency for Cultural Affairs, Tokyo National Research Institute for Cultural Properties (TNRICP) continues to support the building of an administrative network to conserve historic settlements in Nepal. On September 23rd and December 1st, 2019, workshops were organized in Kirtipur municipality with participation of engineers in charge of conservation of historic settlements from relevant municipalities. In response to their outcomes, “the third Mayors’ Forum on Conservation of Historic Settlements in Kathmandu and Kavre Valley” was held on January 5th, 2020, under the joint auspices of Kirtipur municipality and TNRICP.
The first Mayors’ Forum was held in 2018 in Panauti municipality for sharing the initiatives and issues related to preservation of historic settlements among the municipalities, followed by Lalitpur Metropolitan City in 2019.
Kirtipur municipality, whose old city area known as “a medieval settlement in Kirtipur” was listed as a UNESCO tentative list for World Heritage site, has been working on establishing its own rules for conservation. Therefore, the theme of this Forum was set as “regulatory framework for conservation of historic settlements,” and through two engineer workshops, the current issues pertaining to the systems were clarified and discussed while sharing information. As a result, the following were spotlighted as issues of administrative organizations and such systems: the existing framework for preservation of historic settlements is not effective since the policy for protection of cultural heritage of monumental nature is not linked with that for urban planning under national administration; some pioneering municipalities preserve their streetscapes under their original regulations, while others are formulating their regulations or criteria by focusing on completely different issues in municipal administration.
Accordingly, at the Forum, an officer in charge of national policy to protect cultural heritage and the one for urban planning reported about their respective conservation systems, and engineers from five municipalities delivered presentations on their legislation and issues to mutually share the tasks under national and municipal administration. Professor NISHIMURA Yukio of Kobe Design University gave a keynote speech titled “Effective Integration between Methods of Urban Planning and Preservation of Historic Settlements” while KANAI Ken, Head of the Conservation Design Section of the Institute, introduced some case studies on the Japanese system for important preservation districts of historic buildings. The Forum was attended by around 120 people, including State Minister of Urban Planning, five mayors and four deputy mayors, as well as engineers and researchers, who proactively exchanged opinions at the end.
Each municipality has several issues on conservation of historic settlements due to lack of financial and human resources, without sufficient support from the national government. Another reason for the ineffective functioning of the existing systems is insufficient basic research on historic settlements or lack of cooperative systems involving researchers and experts.
Consideration to lay the foundation to operate the network for conservation of historic settlements involving research institutions has just begun. It is anticipated that the autonomous and continuous cooperation among the persons concerned is strengthened to achieve a better environment around the historic settlements as well as its preservation.
A scene from the ICC meeting
Dynamic cone penetration testing
Tokyo National Research Institute for Cultural Properties has been providing technical support to the Authority for the Protection and Management of Angkor and the Region of Siem Reap (APSARA) for the conservation and sustainable development of the ruins of Ta Nei Temple in Angkor, Cambodia. TNRICP dispatched a total of six members including outside experts to Cambodia from December 1st to 21st, 2019 in order to report the progress of dismantling the East Gate of the temple at the meeting of the International Co-ordinating Committee for the Safeguarding and Development of the Historic Site of Angkor (ICC), and investigate causes of uneven subsidence at the basement and floor of the East Gate.
At theICC meeting at the APSARA headquarters office on December 10th and 11th, we delivered a report in association with Mr. Sea Sophearun from APSARA. Approval was granted to proceed with the conservation work further while utilizing the results of the dismantling survey, including a site visit by four specialized members of the committee. We also collected the latest information by exchanging opinions with persons in charge from APSARA, as well as experts within and outside Cambodia.
To investigate the causes of uneven subsidence, we analyzed the old ground surface, and dug the southeast and northwest internal corners till the bottom of the stone foundation to check the condition of the East Gate base. This confirmed that the East Gate basement was made of roughly formed sandstone exterior, laterite groundwork, and internal landfill. It was also determined that the entire basement structure was built on a manmade soil layer using fine grains of sand. This sand layer seems to be the one that lends stability to the foundation on which the building was constructed. Similar techniques can been observed at other temple ruins in Angkor.
After partially removing the floor pavement stone blocks, the bearing capacity of the foundation landfill was investigated with a dynamic cone penetration testing device in cooperation with Professor Dr. KUWANO Reiko from the Institute of Industrial Science, the University of Tokyo. The testing disclosed that the fragility of laterite used as base layer of the floor pavement and the strength of foundation landfill differed by location. This could be one of the causes of uneven subsidence.
Based on the outcomes of this survey, we will examine how to improve the basement structure to ensure complete restoration of the East Gate.
Dismantling work with a crane truck
Head of a statue found inside the East Gate
Tokyo National Research Institute for Cultural Properties provides technical support to the Authority for the Protection and Management of Angkor and the Region of Siem Reap (APSARA) for the conservation and sustainable development of the ruins of Ta Nei Temple in Angkor, Cambodia. During the period from September 7th to November 5th, 2019, the Institute dispatched a total of six members, including outside experts, to Angkor.
In this restoration project of the East Gate of Ta Nei Temple, APSARA is responsible for implementing the dismantling work, while the Institute provides technical assistance, mainly on restoration methodologies, in addition to cooperation indocumentation and other scientific surveys .
The team began dismantling the roof of the gate by using a crane truck after praying for the safety of all persons involved in the work at the ground-breaking ceremony on September 12th. The numbered stone blocks were removed one by one from the top during which each block was measured, photographed, and assessed with its damage condition.
After dismantling the roof part, the tree roots and anthills invading the structure were removed, and the collapsed stones inside the building were taken out. Most of the collected stones, almost 70 in total,were revealed to fell down from the roof or pediment. They seemed to collapse naturally due to aging. Beneath the collapsed stones, broken head (measuring approximately 56 cm in height) of a statue, which could be identified as Lokesvara, was found leaning against the western wall of the south wing. This statue must be significant in that it is expected to shed light on the history of Ta Nei Temple, much of which is still unknown. After the find was documented with photography and 3D scanning to be described, it was moved to store at a APSARA’s facility for further study.
In cooperation with the OISHI Laboratory at the Institute of Industrial Science, the University of Tokyo, the walls and the interior of the gate were documented with a 3D laser scanner, while the Structure from Motion (SfM) technique was used to record the walls in conjunction with surveying the structure in detail. Dismantlement of the walls started on October 16th and ended safely on November 5th with the completion of the required recording.
A series of surveys following the dismantlement process disclosed the fact that the structure was deformed, partly because of the invasion of tree roots and anthills into the stone joints. Uneven subcidence of the foundation and floor surface suggests that the base structure might have some defects. The recovery of structural soundness requires the improvement of the base structure after clarifying the deterioration mechanism. Therefore, we will dispatch the staff again in December to excavate part of the foundation and investigate the ground.
Besides, we attended the meeting of the International Coordination Committee for the Safeguarding and the Development of Preah Vihear Temple (ICC-Preah Vihear) at the APSARA headquarters office on September 18th to collect the latest information. While exchanging opinions with and collecting information from international experts, we will try to find the most appropriate way to conserve the Angkor ruins in cooperation with APSARA.
Examining utilization strategies with local experts
Yuwakha village in Punakha, one of the surveyed settlements
Since 2012, Tokyo National Research Institute for Cultural Properties (TNRICP) has been conducting joint architectural research on rammed earth buildings in Bhutan with the Division for Conservation of Heritage Sites (DCHS), Department of Culture, Ministry of Home and Cultural Affairs, the Royal Government of Bhutan. From this fiscal year, TNRICP has started the Networking Core Centers for International Cooperation in the Conservation of Cultural Heritage Project, which was commissioned by the Agency for Cultural Affairs, with the objective of providing technical support and capacity building for the conservation and utilization of historic buildings in Bhutan. As a part of this project, a team of 11 experts, including TNRICP staff and outside experts, conducted on-site fieldwork from 20th to 28th August, 2019.
The field survey was jointly conducted with DCHS staff and covered traditional houses in the dzongkhags (districts) of Thimphu, Punakha, and Haa. The three main objectives were establishing a methodology for their conservation and repair, studying alternatives for their sustainable utilization, and clarifying the criteria for their evaluation as cultural heritage. Regarding the methodology for conservation and utilization, three traditional houses, which had been previously identified on the basis of features that indicated an early construction date, were selected as case studies. The potential methodologies for the seismic retrofitting of their rammed earth walls and the repair of their wooden members were studied. Furthermore, their potential use, compatible both with the owner’s demands and with the conservation of their value as cultural heritage, was examined during a discussion that involved DCHS staff, local architects, and owners. Regarding the evaluation of traditional houses as cultural heritage, comprehensive surveys were conducted in several settlements, and a potential method for the classification of traditional houses as well as a set of criteria for their designation as cultural properties was studied.
In addition, a Memorandum of Understanding referring to this project was signed at the Department of Culture, and a meeting was organized with the DCHS to discuss the results of this survey as well as the future prospects and needs of the Bhutanese counterparts.
In the future, we expect to continue cooperating with Bhutanese experts through on-site surveys and workshops to establish a methodology for the conservation and utilization of historic buildings suited to the Bhutanese reality.
Classroom lecture at Tokyo National Research Institute for Cultural Properties
Tour of restoration conditions at the Shinmachi-Furumachi District in Kumamoto City
A civil war broke out in Syria eight years ago in March 2011, and it seems there is no end in sight. Apart from the human cost of war, the much precious cultural heritage was also lost.
The Japanese government and the United Nations Development Programme (UNDP) began providing cultural heritage aid to Syria in 2017. From February 2018, the Archaeological Institute of Kashihara, Nara Prefecture, in association with academic organizations such as the University of Tsukuba, Teikyo University, Waseda University, Chubu University, and the Ancient Orient Museum, has been accepting Syrian specialists and providing them training in the fields of archeology and restoration. Tokyo National Research Institute for Cultural Properties is also participating in this project.
Following training seminars on conservation and restoration of paper cultural properties held in May 2018, this year, two Syrian specialists were invited to undergo training in “Research Planning Methods to Restore Historical Cities and Buildings” conducted from July 24th to August 6th.
Many historical cities such as the ancient city of Aleppo were engulfed in war, and many historical buildings were devastated. In the first half of this year’s training, seven specialists gave classroom lectures on surveying damage to historical buildings and making emergency repairs, structural safety diagnosis method, documentation and database creation method, restoration plan creation method, and restoration and preservation system creation method. For the practical aspect that comprised the second half of the training, participants inspected the restoration status of historical buildings and townscapes devastated by the 2016 Kumamoto Earthquakes, including Kumamoto Castle, the Shinmachi-Furumachi District, Kumamoto University, and the Eto-yashiki (Eto estate), which is registered as an important cultural property.
The participants also heard stories told by the people in charge. They visited Preservation Districts for Groups of Traditional Buildings in Kyoto and Nara and saw examples of repairs and applications of historical Japanese buildings.
We would once again like to thank the specialists, related organizations, and personnel-in-charge for their support.
Tokyo National Research Institute for Cultural Properties plans to continue support activities for Syrian cultural heritage in the future.
Participants at the expert meeting
Case study of the utilization of traditional houses (Fukusumi)
Tokyo National Research Institute for Cultural Properties (TNRICP) provides the Royal Government of Bhutan with technical support and human resource development for heritage conservation and sustainable utilization of historic buildings, including traditional houses, under the scheme of International Cooperation Project for Cultural Heritage by the Agency for Cultural Affairs in Fiscal Year 2019. TNRICP invited two staff members of the Division for Conservation of Heritage Sites (DCHS) from June 23rd to 28th to Japan to hold the first expert meeting and a case study tour in western Japan.
At the meeting, Mr. Yeshi Samdrup of DCHS presented a report on the progress of the development of the legal system concerning cultural heritage, and Mr. Pema Wangchuk of DCHS made a presentation on the prospects for the protection of traditional houses and settlements. Participants shared the recent challenges and dilemmas concerning the protection of cultural heritage in Bhutan through their presentations and the subsequent discussion. The subject of the field survey scheduled for this August was also discussed, and the specific survey method has been almost fixed.
In the case study tour, we visited the Ozaki family residence (Yurihama, Tottori), which is undergoing conservation work, and the Open Air Museum of Old Farm Houses (Toyonaka, Osaka) where typical traditional houses from all over Japan have been collected to study basic concepts of the protection of traditional houses as cultural property in Japan. We also visited historic towns and villages where historic townscapes have been rehabilitated, namely Shikano (Tottori), Oyacho-Osugi, Sasayama, Fukusumi (all above, Hyogo), and Miyamacho-Kita (Kyoto), to spread knowledge about community involvement and heritage tourism where traditional houses can be utilized as accommodation. The invitees were particularly interested in the nongovernmental management of cultural heritage that should be treated under the new law in Bhutan, and there was a lively exchange of views and opinions with the local presenters at each site.
We would like to extend our deep appreciation to all the people involved in the tour for providing this opportunity.
Site visit by members of the Ad Hoc Experts Group of ICC
Removal of scattered stone blocks with the mobile crane
Tokyo National Research Institute for Cultural Properties (TNRICP) provides technical support to the Authority for the Protection and Management of Angkor and the Region of Siem Reap (APSARA) for the conservation and sustainable development of the ruins of Ta Nei Temple in Angkor, Cambodia. TNRICP dispatched a total of five staff members to Cambodia from May 19th to June 29th, 2019 in order to carry out preparatory work before the examination of the restoration plan for the East Gate by the International Coordinating Committee (ICC) and the start of the restoration work.
APSARA and TNRICP submitted the plan for dismantling the structures to the ICC technical session, which was held on June 11th and 12th. As a result of careful deliberation including a site visit by the three members of the Ad Hoc Experts Group, the plan was adopted as proposed with minor corrections. As necessary preparation for the restoration work, we cleaned out and organized scattered stone blocks around the East Gate, and also carried out excavations for drainage route examination.
We recorded and numbered scattered stone blocks and moved them out of the way of the restoration work. Thanks to the mobile crane provided by Nara National Research Institute for Cultural Properties (NNRICP), which is restoring the Western Prasat Top Site, we were able to move the stone blocks in a short time.
During the excavation we tried to clarify the difference in the old ground surface level between the northeast end of the Cruciform Terrace and around the East Gate, in order to examine the natural drainage route from the East Gate area. The elevation around the East Gate is lower than the surrounding area, and it is feared that rainwater may stagnate there, which is why we plan to set up a drainage channel to the North Moat for future maintenance. In addition, we found laterite stone paving which is presumed to be a part of the approach that connects the Cruciform Terrace and the East Gate. It is expected that further excavations will provide clearer information.
Investigating a sample from target building
Sample with the finishing layer from each period carved out in tiers
As part of this project commissioned by the Agency for Cultural Affairs of the Japanese Government, a compositional analysis of the finishing layer of a group of buildings adjacent to Aganchen Temple at Hanumandhoka Palace, Kathmandu, was performed using an X-ray fluorescence spectrometer, etc., from February 22nd to 28th, 2019, with permission from the Department of Archaeology, Government of Nepal.
On-site surveys conducted so far have revealed that a number of extensions and structural alterations had been made to these buildings. In particular, the wall finish recoating history and the remaining finishing layers at hidden areas of retrofitted support members are important clue in learning about the changes to the buildings. Study on the specifications and coloring of each recoated layer has continued.
This time, the composing materials of the finishing layers were identified in order to understand how specifications changed according to the times, and a scientific analysis was performed using an X-ray fluorescence spectrometer and a Raman spectrometry system to examine the history of extensions and structural alterations.
A fragment of the finishing layers investigated comprised a maximum of 10 different sets of layers. Surface and undercoat layers from each period were carved out in tiers and analyzed.
Red iron oxide and minute amounts of gold were confirmed in red-colored areas of the old mural painting layer, and a spectrum quite similar to lapis lazuli was derived from the sky-blue finishing layer recoated in later years. While a detailed analysis of the derived data has yet to be performed, it can be inferred from the use of such precious materials that these buildings had continued to be used as important ritual or residential spaces for a royal family since their initial construction in the 17th century.
In the process of surveying the remains, a mural painting was discovered behind the extended wall section, and it is possible that this mural dates back to a period just after the original construction of the building. Further surveys, including through scientific methods, such as the one used this time, and studies of appropriate preservation measures are still needed.
Hereafter, we will continue to elucidate the history concealed in the buildings themselves, and while preserving such significant material evidence, we will consider how to go about restoring these buildings in association with the Nepalese counterpart.
Unearthed west wing of the terrace structure
Tokyo National Research Institute for Cultural Properties has been engaged in technical cooperation with the Authority for the Protection and Management of Angkor and the Region of Siem Reap (APSARA) for the project to conserve and manage Ta Nei Temple in Cambodia. From August 20th to October 7th, 2018, the fourth archaeological investigation was conducted.
With the cooperation of staff from APSARA, the archaeological investigation was carried out at the terrace structure on the upper surface of the embankment of the East Baray reservoir discovered thus far. In addition, the approach, which is expected to have existed between the terrace structure and the east gate of the temple, was also investigated.
As for the terrace structure, because of the extension of the investigation area to the west, the west wing, which measures 6 meters east to west and 2.5 meters north to south, was unearthed; this was in addition to the east wing discovered last year. Although the upper stone materials were missing, the foundation existed in all circumferences. This discovery resulted in clarifying the fact that the structure is 18 meters in scale from east to west. According to a parallel case, the original terrace structure was assumed to be cross-shaped along with the north and south wings, which are still unexcavated. Further excavation should provide evidence that backs up this speculation.
As for the approach, we attempted to clarify its width and the condition of its sides by further expanding the 2017 investigation area. This resulted in revealing the fact that the approach is approximately 11 meters in width and that certain facilities might have existed on both sides, which are around 50 centimeters higher than the approach.
We are planning to prepare explanation boards for tourists visiting the site. In parallel with the academic investigation, we will also proceed with establishing a management system for access and utilization.
Removing the Collapsed Wooden Members of the Old House
Memorial Service at Changangkha Lhakhang
In cooperation with the Division for Conservation of Heritage Sites, Department of Culture, Ministry of Home and Cultural Affairs of Bhutan, we surveyed traditional houses built with the rammed earth construction technique in the capital, Thimphu, and the Paro Dzongkhag from July 16th to July 24th, 2018.
We focused on an old house located in Kabesa Village in the northern outskirts of Thimphu as the best example of a house built in an ancient style among the old farm houses we discovered through the surveys. Regrettably, the upper floors and other wooden elements of the house, which had been left uninhabited for many years, collapsed last year, but its external walls built with rammed earth remain. As a result of emphasizing the significance of preserving this house at a workshop held in the city in March 2018, the owner withdrew his intention to demolish the house, and a movement began toward its restoration. In response to this, we collected the wooden members of the house, and individually recorded and identified their original locations, before placing them into temporary storage. We confirmed that the members were far less damaged or missing than expected, which enables an accurate restoration. We expect that examination of concrete restoration and utilization measures will progress after this.
Since 2016, the research and study of old houses in Bhutan has been conducted under Grants-in-Aid for Scientific Research. During our stay in Bhutan this time, we received the sad news that the representative of the research project, Dr. Nobuo KAMEI, Director General of Tokyo National Research Institute for Cultural Properties, had passed away. The Bhutanese people involved in the cooperation project proposed that we should hold a memorial service for the DG at Changangkha Lhakhang, a venerable temple overlooking the city of Thimphu. The staff members involved in the joint activities gathered there to pray for the repose of his soul by lighting 108 votive candles.
Survey of tile-roofing specifications at Aganchen Temple
Workshop in Sankhu on the conservation of historic settlements
As part of the above-mentioned project commissioned by the Agency for Cultural Affairs, we have continually provided technical assistance to Nepal. Already, in 2018, we have dispatched on-site research missions in February, March, April, and May.
For the rehabilitation of the Aganchen Temple and its associated buildings in the Hanumandhoka Palace in Kathmandu, we surveyed detailed specifications and traces of transformation of the brick masonry surfaces of the inner walls whose finishing layers had peeled off. The brick masonry, all of which looks the same, differs in material, dimension, or construction method according to age. Evidence remains at places where the wall or opening was altered. Observation following the cleaning inside cracks blocked by the rubble that had collapsed from the upper section, revealed numerous clues to retrace the history of various extensions and alterations since its construction in the 17th century. The number of targets to be clarified through further research has increased, including the existence of an unknown mural painting unveiled during this process. We have further increased our awareness of this building’s great value as physical evidence to comprehend history, in addition to the highly elaborate work applied to the subsequently altered sections as a particularly important building in the palace.
As preparations for the rehabilitation work are being made under the direction of experts dispatched from Japan International Cooperation Agency (JICA), we are cooperating in the examination of concrete conservation methods and consultation with the relevant institutions in Nepal. Although the work has not yet begun due to various difficulties in procedures, as a united team we would like to make every effort to conserve the building’s value as a cultural heritage.
Meanwhile, we have continued to cooperate in the conservation of historic settlements in the Kathmandu Valley. In May 2018, we organized a workshop at the historic settlement of Sankhu, inscribed in the Tentative List of World Heritage Sites of Nepal, but seriously damaged by the earthquake, for those officers in charge of public administration in each city holding jurisdiction over historic areas and settlements. Under the theme of conservation of historic water channel networks, participants from six cities discussed their current situations and issues together with urban design experts, and developed six suggestions. The outcomes will be shared with those concerned in other cities who could not attend the workshop this time. We expect the suggestions will help to conserve each historic settlement.
A scene of the workshop
Old traditional house proposed as a subject to be preserved (in Haa province)
The traditional houses in the western region of Bhutan are built with earth rammed down into a formwork, a method called rammed earth construction. These houses have become a key element of the beautiful cultural landscape of the country with lush greenery. However, unlike religious and administrative buildings such as temples and castles, they are not protected legally as cultural heritage, and precious old houses are being lost rapidly due to natural disasters, modernization, and various other factors.
Since 2012, Tokyo National Research Institute for Cultural Properties has been conducting architectural studies and research on buildings constructed in the rammed earth method jointly with the Division for Conservation of Heritage Sites, Department of Culture, Ministry of Home and Cultural Affairs in Bhutan. During the process, both sides became once again strongly aware of the value of old houses as cultural heritage and the urgency in their conservation. Therefore, on March 13th, 2018, we organized a workshop joined by Japanese and Bhutanese experts, persons in charge from the Ministry of Works and Human Settlement and local governments, and owners of traditional houses at the headquarters of the Department of Culture in Thimphu. We shared information about the survey outcomes including the chronology and the changing process of traditional house architecture, the legal framework for protection of cultural heritage in Bhutan, and how Japanese traditional houses are protected. We also exchanged opinions on specific traditional houses to be preserved and related future issues. We hear that soon after the workshop, a positive effect began to appear through a movement toward the preservation and utilization of important houses. We expect its great contribution to the consolidation of the legal system for cultural heritage, which has been stagnant in the country.
Excavated terrace structure
Survey of the current condition of the temporary supports
The Tokyo National Research Institute for Cultural Properties has been carrying out technical cooperation with the Authority for the Protection and Management of Angkor and the Region of Siem Reap (APSARA) in order to draft a conservation and management plan for Ta Nei Temple in Cambodia. From November 28th through December 8th, 2017, we conducted an archaeological investigation and a risk assessment for the structures at Ta Nei Temple for the second time.
The main purpose of the archaeological investigation was identifying the remains of the east approach to the temple located at its front and the remains of a structure situated on the upper surface of the embankment of the East Baray reservoir discovered during the first investigation in July. The excavation was conducted jointly with staff from APSARA and with the cooperation of the Nara National Research Institute for Cultural Properties.
First, we set up and excavated a trench 2 m wide from east to west and 5 m long from north to south, approximately 50 m to the east of the east gate. We discovered a hardened surface, presumably the old approach to the temple, 70 cm beneath the current ground surface. The hardened surface was composed of yellow soil covering a layer of small sandstone gravel 5 mm in size overlapped on a layer of fist-sized sandstone cobbles.
In addition, we set up and excavated a trench 11 m long from east to west and 1 m wide from north to south on the embankment of the East Baray on the prolongation of this approach way. We found a laterite stone surface 30 cm beneath the current ground surface (Figure 1). Considering the surrounding topography and the distribution of exposed laterite, these remains can be presumed to form part of a terrace structure approximately 20 m long from east to west and 15 m wide from north to south.
Regarding the risk mapping of the site, we examined how to renew the existing temporary supports. Wooden supports had been installed in 16 places where there were safety concerns such as potential collapse of main structures, including the central tower, the east tower, and the inner gallery. However, apart from obstructing the view of the site, these supports are in need of renovation, as in the 20 years that have passed since their installation decay of timber members and loosening of joints have become apparent. Thus, we observed and recorded the current condition of these supports, and studied improvement proposals including a change to a more durable material and the adoption of a design enabling fine adjustment.
Trench excavation and the ditch revealed (created with SfM)
The Tokyo National Research Institute for Cultural Properties is providing technical support to the Authority for the Protection and Management of Angkor and the Region of Siem Reap (hereafter APSARA) to draft a plan for the conservation and management of Ta Nei Temple. From July 16 to 30, 2017, we carried out an archaeological excavation and risk assessment of the buildings (Figure 1).
Our excavation was mainly to identify remains of the East Approach to the temple, located at its front. We worked with APSARA staff with the cooperation of the Nara National Research Institute for Cultural Properties. When we cleared the underbrush along about 100 meters from the Eastern Gate of the outer enclosure to the East Baray reservoir, we discovered remains of a laterite terrace on the bank of the reservoir, suggesting the high likelihood of this location being the starting point for an approach leading to the Eastern Gate.
We first opened a trench measuring 2 meters east-west and 10 meters north-south about 12 meters east of the Eastern Gate (Figure 2). Our excavations revealed a ditch running east-west 50 cm below the current ground level. The ditch was about 2 meters wide and filled with amounts of fine chips of laterite (1cm-0.5cm in diameter), suggesting the possibility of an approach. In addition, both sides of the ditch were covered with fist-sized sandstone cobbles.
For the purpose of finding the rest of this ditch as well as to verify the initial ground level, we opened a trench measuring 2 meters east-west and 2.5 meters north-south along the Eastern Gate and dug down. This trench revealed a sandstone cobbles covered surface that spread out over the entire surface 50 cm under the current ground level, and we were unable to detect any remains of the ditch.
We are planning another excavation in November to determine further details of the Eastern Approach and to identify the entirety of the newly discovered terrace-like remains.
One of the major charms of Ta Nei Temple is its ancient ruin-like setting, relatively untouched by human hand compared to other Angkor ruins. On the other hand, there is a need to prevent further collapse, in part to ensure the safety of visitors. Therefore, it is urgent for support structures to be installed and updated in a planned, organized manner on the basis of structural risk assessment of the overall temple complex. We decided to create elevation maps using SfM and conduct a risk assessment starting from the major buildings along the central axis. We started with two buildings with which we worked to establish the procedures for such operations. This work is currently being continued by APSARA staff.
To preserve the buildings and surroundings in good condition, as well as to help visitors to the area better understand the significance and value of the site, we wish to intensify our cooperation toward academic elucidation and achievement of effective conservation.
MOU signing ceremony in Thimphu
Investigation of traditional private residential buildings (Tshosa Village, Punakha District)
Since fiscal year of 2011, the Tokyo National Research Institute for Cultural Properties (TNRICP) has been cooperating with the Department of Culture (DOC) of the Ministry of Home and Cultural Affairs of Bhutan on the study of traditional rammed earth buildings. This cooperation was triggered by the successive earthquakes in 2009 and 2011 that caused severe damage to buildings constructed with the traditional method. The urgent task of striking a balance between ensuring safety by improving the seismic capacity of both public and private buildings and protecting/inheriting the traditional method that is still widely used in housing construction, etc. has become the center of attention.
The research programme centered on the buildings constructed with earth rammed inside the wooden formwork from the perspective of both understanding and analyzing structural performance and clarifying traditional architectural techniques. Meanwhile, a legal framework for the preservation of private residential buildings as cultural heritage was being developed. Therefore, since fiscal year of 2016, investigation efforts have focused establishing basic typological and chronological indexing of rammed earthen traditional houses under the Grant-in-Aid for Scientific Research (“Research on the typology and chronology of rammed-earth buildings in Bhutan,” Principal Researcher: Nobuo KAMEI, Director General of TNRICP).
In the joint field survey conducted from March 4th to 16th, 2017, a measurement survey, among others, was conducted on a total of 16 traditional houses in Thimphu and Punakha prefectures, where efforts were made to collect information for studies of the original building shape, construction period, history of modification, etc., including observation of remaining traces and interviews with residents.
Further, during this time, a research cooperation agreement was signed by the representatives of both parties, the aim of which was to further strengthen cooperative relations between the Institute and DOC. While considering the feelings of the people of Bhutan, who are keen to continue protecting their tangible and intangible traditional culture, we will continue working on this investigative research in hopes of contributing to the clarification of cultural values of historic architectures.
The workshop in progress
For more than 15 years the Tokyo National Research Institute for Cultural Properties (TNRICP) has been collaborating with the Cambodian national authority for the protection and management of Angkor and the region of Siem Reap (APSARA) in various ways, including conducting joint research and personneltraining. Over this period of time, fieldworks have been conducted mostly at the Ta Nei Temple ruin of the Angkor onuments. The most recent workshop was held in Cambodia from January 26th to 28th, 2017 to support the creation of conservation, management and enhancement plan for the site.
Joining the workshop were H. E. Mr. Ros Borath, Deputy Director General of APSARA, and other experts from the organization’s sections on the conservation of monuments, tourism, forestry and hydrology. A total of more than 20 staff members attended. On the first day, lectures were given at the APSARA head office addressing basic outlining and planning procedures for the conservation and management of archaeological sites. The second day was a site visit to Ta Nei and its vicinity to survey and confirm the current state of the area. On the third day, the participants returned indoors to discuss the basic direction for moving forward with planning and how to carry out the conservation and enhancement project after this.
Ta Nei Temple is a major archaeological ruin within the core zone of the Angkor World Heritage Site that is constantly filled with tourists, but it still retains the striking atmosphere of a lost temple overgrown by jungle forest. A major outcome of the workshop discussions was the agreement on significant issues such as the determination to upkeep the temple, maintaining its present state so that people can safely tour the ruin, and to restore the original access route to the temple so that visitors can get a physical sense of the site’s relationship to nearby Angkor sites. There was also agreement that all the concerned sections would work together on steadily pursuing specific areas of endeavor, including archaeological excavations and other necessary surveys. This project is being positioned as a pilot model project for the maintenance of ruins conducted by Cambodian initiative, and TNRICP will continue to provide the necessary technical assistance to enable the work to be carried out properly and smoothly.
Aganchen Temple of Hanumandhoka palace, Kathmandu
Sorting/storage work of architectural members collected from the collapsed Shiva Temple
A team of experts was dispatched to Nepal on a further four occasions up to March 2016 for the Investigation of Damaged Cultural Heritage in Nepal, which was introduced in the last issue and was conducted under the Project for International Contribution to Cultural Heritage Protection, which was commissioned by the Agency for Cultural Affairs of Japan. The experts engaged mainly in the following activities.
Survey on Building Damage
The experts checked the state of damage to traditional buildings centering on Dubar Square, which is part of the World Heritage site of Kathmandu Valley. Aganchen Temple (partially damaged) and the Shiva Temple (totally collapsed), both located inside Hanumandhoka Palace, were selected as the target of detailed surveys.
Survey on Traditional Building Techniques
Among others, a survey was conducted on the distinctive traditional building techniques of the Newar culture, including building elements that had been revealed for the first time by the damage, such as the timber pillars concealed inside brick walls. Regarding Aganchen Temple in particular, the experts conducted measurement surveys, checked the state of damage in detail, and studied past alterations in order to assess the present situation and assist the restoration.
Building Structure Survey
The experts conducted surveys mainly on two multi-tiered tower-style temples in the square, including measurements using a 3D laser scanner, a detailed investigation of the state of damage, and measurement of their vibration characteristics. Using a model compiled on the basis of the results, they carried out a structural analysis and examined the damage mechanism and other issues.
Emergency Protection Work
The team of experts sorted, stored, and documented architectural members retrieved from the collapsed building of the Shiva Temple and offered advice on work methods to personnel of Nepal’s Department of Archeology and other organizations. All of the components were arranged by type and stored in temporary shelters, and a survey was conducted on the state of damage to each part as well as on past modification of the building.
Survey on Historical Settlement
The experts also visited the village of Khokana, which has an old townscape and is registered on the World Heritage Tentative List, investigating the state of damage, the transformation of housing up to the present, and the village’s intangible heritage value such as those of various cultural spaces. Here they carried out the survey in collaboration and cooperation with a local residents’ organization that is making strenuous effort both to reconstruct lives as quickly as possible and preserve the historical townscape.
Meanwhile, three Nepalese engaged in the preservation of cultural heritage in the Nepalese government and the UNESCO office in Nepal were invited to Japan in February 2016 for the seminar on Cultural Heritage Damaged by the 2015 Nepal Gorkha Earthquake, which was held at the National Research Institute for Cultural Properties, Tokyo on February 5th. At the seminar, the three Nepalese invitees gave presentations on the situation after the earthquake, restoration measures, and other issues, and then the Japanese experts participating in the project gave interim reports on survey results in their respective special fields. As difficult conditions continued to prevail in Nepal, the two sides were able to share the latest information and, through discussions, exchange opinions on how to respond to damaged cultural heritage and so on.
Through such cooperation, we hope to continue providing appropriate assistance to Nepal’s efforts to restore damaged cultural heritage and transferring Japanese technology, such as survey methods for the repair of cultural properties.