Investigation of Coloring Materials Used for Kina-Saffron-Shu-Honpo Kote-e Kura (Warehouse Decorated with Trowel Paintings)

Kina-Saffron-Shu-Honpo Kote-e Kura

Flaking and chipping

　Kina-Saffron-Shu-Honpo Kote-e Kura in Nagaoka City, Niigata Prefecture was completed in 1926 by the plasterer KAWAKAMI Ikichi. The artwork was commissioned by YOSHIZAWA Nitarō, the founder of Kina-Saffron-Shu-Honpo (i.e., Kina Saffron Winery). The kote-e* (plaster reliefs) are mainly positioned around eaves and doors of the warehouse structured of lumber and with mud wall. The kote-e reliefs are three-dimensional representations of Daikokuten (Japanese deity of fortune and wealth) and animals and plants, and were created with the impasto technique mainly using plaster. The use of red and blue colors in the reliefs creates a contrast that enhances the three-dimensional visual effect.

　Although these kote-e are placed in a harsh environment with exposure to rainfall and wind, they have remained in a relatively good condition considering that they were created almost 100 years ago. This can be attributed to the efforts made by people to protect the artwork and hand down it to generations as well as to the characteristics of the plaster and the ingenious plastering techniques.

　Nonetheless, some damage such as flaking and chipping of plaster and color can be seen in every kote-e on careful observation. Hence, responding to the request by Nagaoka City, the owner of the warehouse, Tokyo National Research Institute for Cultural Properties (TOBUNKEN) visited the site on November 11th, 2022 and conducted sampling investigation of color and plaster as a part of pre-investigation for conservation and restoration, which has been deemed necessary for the near future. Sampling investigation is conducted by extracting small samples from the target materials; this practice is also described as “destructive investigation.” Although the word “destructive” may indicate something “bad,” it is not so. Sampling investigation enables us to obtain reliable information that cannot be obtained by simply checking the surface. Therefore, destructive investigation, in fact, enables safer and superior conservation and restoration.

　We will effectively utilize the outcome analysis of this investigation for planning the conservation and restoration project so that the Kote-e Kura, which has been maintained by prior generations, can be passed down to future generations and it remains well-preserved for at least another 100 years.

*Kote-e: colorful Japanese plaster reliefs created using a trowel

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.