|■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
How a workshop is being conducted
The Department of Art Research, Archives and Information Systems of the Tokyo National Research Institute for Cultural Properties organized a workshop on May 30, 2017, when Takuyo YASUNAGA (a researcher of the Dept.) gave a presentation on research titled the Historical Position of “Hakubai-zu byobu” by Goshun (housed by the Itsuo Art Museum).
After working as a disciple of Buson YOSA, Goshun (1752-1811) inherited Okyo MARUYAMA’s painting style. Goshun is known as a painter who established a painting school called the Shijyo school. One of his representative paintings, “Hakubai-zu byobu (the folding screen of white plum blossoms)” (an important cultural property) is a fantastical piece of work in which a small earth mound and three white plum trees that spread their branches are drawn on a pair of six-panel folding screens to which a coarse-grained fabric made from pale blue-dyed yarns is applied. These screens are estimated to have been produced between 1787 and early years of the Kansei era (1789-1801) based on a technique called tsuketate he employed in drawing the branches of plum and a style of calligraphy for his signature. They are one of the examples that were created when Goshun changed his painting style from a Buson style to the Okyo counterpart.
As the initial step, YASUNAGA analyzed the expressions and materials of the painting meticulously, thereby shedding light on issues of incorporating an Okyo style in a painting on the subject of plum. He then went on to point out that a Nanpin style based on the learning of Buson’s paintings and an influence of Chinese paintings were identified in its unusual background expression on the fabric made from pale blue-dyed yarns. Furthermore, with respect to the use of a quite special base material that appears to be a cloth made from kudzu, YASUNAGA extrapolated the base material of the work through a comparison with some examples that use such cloth by other artists than Goshun. He also indicated that the use of such cloth was possibly associated with interaction between Goshun and men of letters in Ikeda. After his presentation, he was bombarded by questions about the use of this special base material and lively discussions were conducted on the possibility of its identification.
Mr. Douglas Brooks (left) and Mr. Seiichi NASU (right)
Ukaibune under construction
Ukai, or a fishing method which uses trained cormorants to catch river fish, conducted in the Nagaragawa River in Gifu Prefecture is now famous as a representative tourist attraction of the prefecture. The ukai fishing conducted in the goryoba, or the Imperial Fishing Ground, is called goryo ukai, which has an important role of serving the caught ayu (sweetfish) to the members of the Imperial Family. Moreover, the technique has been designated as an important intangible folk cultural asset of Japan. Thus, ,ukai is historically and culturally significant. One of the essential elements to support the ukai fishing technique is the cormorant fishing boat called ukaibune that is helmed by the usho, the cormorant fishing master. There is a fear, however, that the technique of building ukaibune will not be handed down to the future generations, as at present, there are only two funadaiku, or boat builders, capable of building this type of boat.
Under these circumstances, a project has started, in which Mr. Douglas Brook, a U.S. citizen, researcher of Japanese boats and funadaiku, who has experience in building tarai bune (tub boat) of Sado and sabani (small sail fishing boat) of Okinawa, has become an apprentice to 85-year old Mr. Seiichi NASU, one of the two remaining ukaibune builders, and is working with his master to build an ukaibune. The Gifu Academy of Forest Science and Culture and the Tokyo National Research Institute for Cultural Properties participate in this project, the former providing a place for boat building and the latter producing a video record.
The building of ukaibune began on May 22, 2017 and is scheduled to be completed in about two months. Agility and gracefulness are required in particular of ukaibune when compared to other wooden boats in general, and therefore, sophisticated techniques are required. It is a major target of this project to accurately and completely record the technique to help hand it down to the future generations.
It is somewhat paradoxical that a non-Japanese is learning and mastering this traditional Japanese technique that is on the verge of extinction. We believe, however, that recording the intangible technique by positively taking advantage of this opportunity is one of the roles our institute should play since the conservation of cultural properties is our mission.
Research on the great Torii of Itsukushima Shrine
The Center for Conservation Science has studied restoration materials for cultural properties.
The great Torii of Itsukushima Shrine is located on the coast. Since it is exposed to the wind, the rain and the waves, we have to select restoration materials with high weathering performance, which can also save restoration time.
Based on the above, we studied which fillers and surface-finishing agents were the most suitable for use in the great Torii from 2010 to 2016. After a small pillar of the great Torii was partially restored last year, we researched it on May 25.
We are going to observe the progress and cooperate with conservators for restoration planning.
We have been conducting a joint project with the Iwate Prefectural Museum to determine the methods to stabilize the paper materials damaged by the tsunami in the City of Rikuzentakata, Iwate. In Iwate Prefecture, many documents and other paper materials were damaged by the tsunami that hit the area in 2011. We have already stabilized approximately 90,000 paper materials, but it is still unclear when we will be able to complete the work of stabilizing all the damaged materials. The joint study conducted up to last fiscal year has enabled us to estimate almost all causes of the odors emitted from the paper materials. In this fiscal year, therefore, we have been working on establishing the methods to eliminate the odors from the stabilized materials, and also on a plan to keep records of the stabilization processes to determine how to improve them and what conditions cause paper materials to develop odors. On May 17, we visited the Iwate Prefectural Museum to discuss plans for this fiscal year as well as to install some equipment, together with our co-investigator, Mr. Hideo AKANUMA, in the conservation and restoration laboratory for tsunami-damaged cultural properties of the Rikuzentakata City Museum, which is located next to the Iwate Prefectural Museum. In this laboratory, we tentatively installed the equipment to monitor water temperature and oxygen concentration levels, and also installed surface temperature/humidity measuring equipment to check the temperature and humidity of the laboratory as well as to identify the transfer of temperature inside it. We plan to conduct joint investigations in June and July, each for a period of approximately one week.
Process of shaping the collected brick samples
Installation of targets for deformation monitoring
The 6.8-magnitude earthquake that struck Chauk on August 24, 2016 caused considerable damage to the Bagan Archaeological Zone in Myanmar, mostly to the brick buildings constructed between the 11th and 13th centuries. The Tokyo National Research Institute for Cultural Properties rushed eight experts from various fields related to the conservation and restoration of historical buildings on two successive missions: the first in September 2016 and the second in October through November of the same year. The missions identified the state of the damage in the cultural heritage and studied its causes and mechanisms. The findings from these missions were published in March 2017 as the Report on the Project “Study on the Earthquake Damage in the Bagan Archaeological Zone, Myanmar.”
In this fiscal year, we are undertaking the above-mentioned technical assistance project (subcontracted by the Nara National Research Institute for Cultural Properties) as part of the “Networking Core Centers for International Cooperation on Conservation of Cultural Heritage Project” commissioned by the Agency for Cultural Affairs, with the aim of providing information and technical advice to help improve the quality of the restoration work currently conducted by local authorities, while continuing to examine the appropriate measures to conserve and restore the damaged cultural heritage buildings. As the first field study for this project, we dispatched a group of three experts to the heritage site from May 17 to 25, 2017, during which the group collected brick samples to use for tests, including for material composition or mechanical strength testing, and also started the monitoring of structural behavior.
By taking into account the types of buildings, year of construction, parts where bricks were used, dimensions of structural members, and other factors, the group collected a total of 24 pieces of damaged structural members as brick samples from the six buildings affected by the earthquake. The collected samples were shaped at the site into a form suitable for tests. In addition, to conduct material testing in Myanmar, they consulted with representatives from the Myanmar Engineering Society (MES) and visited its testing facility.
As for the monitoring of structural behavior, the group installed crack gauges and targets for deformation monitoring on the three buildings (two temples and one pagoda) where typical crack and deformation patterns had been found during the study conducted in the previous fiscal year, and then measured their initial values. By continuously monitoring the progress of damage and deformation, we expect to be able to accumulate data over time that will be useful not only for assessing risk levels, but also for developing maintenance plans for the conservation and restoration of the cultural heritage buildings.