About the Shosoin Repository
The Shosoin Repository was originally a storehouse of the temple Todaiji, and had been used for storing the treasures since the Nara period. The building is constructed of Japanese cypress (hinoki) and has a hipped roof covered with traditional tiles. It measures 33 meters in length, 9.4 meters in width, and 14 meters in overall height. The floor is raised 2.7 meters above the ground supported by forty of 60cm-diameter column standing on the foundation of natural stone, such that it is effective on prohibiting ingress of pest and preventing dampness.
The building is divided into three rooms, respectively the North Section, Middle Section and South Section (from right to left on the photograph). Architecturally, the North and South Sections are individually built with azekura construction, in which roughly hewn three-faced timbers are stacked horizontally at all four sides so as to intersect at the corners, creating the corrugated external walls. The internal walls dividing the sections are flat on the sides facing the North and South Sections, and corrugated on the Middle Section sides. Whereas, the external wall of the Middle Section is built with itakura construction, using thick flat boards. Each section has an entrance door facing east, and internally two floor levels.
Historically, the North Section was mainly used for accommodating the offerings by the Empress Kōmyō, and had been kept locked under imperial seal. The Middle and South Sections had been used for storing materials belonging to the Todaiji. While unlocking the Middle Section had also required permission by empire, the South Section remained under control of the temple until the Meiji period.
Despite the age of the treasures, they are in a well-preserved condition. This possibly attributes to the limited access and given care through history, the structure of the repository and the surrounding environmental condition. It is also due to the fact that they had been originally stored in wooden chests. These chests had provided a preservation condition to the treasures by buffering internal humidity fluctuations and creating a barrier against light and pollutants.
Through history, the repository had seen a number of incidents, such as the siege of Nara by Taira no Shigehira in Jishō 4 (1180), the North Section struck by lightning in Kenchō 6 (1254), and the burn down of the Great Buddha Hall during the battle of Miyoshi and Matsunaga in Eiroku 10 (1567). Despite of these, the repository has not been severely damaged and remained to date. Nevertheless, the building has undergone a number of major and minor restorations throughout periods in order to keep it maintained from damages through its ageing. As an example of previous restoration work, the iron strips fastened to the columns under the floor, and the copper plates protecting the edges of joists below the floor can be pointed. These were added during the repair in the Edo period.
It is still debatable exactly when the repository was built, because there is no written record ascertaining its establishment. According to a historic document, it is evident that it had already existed in the third month of Tenpyō Hōji 3 (759). There has been also an argument on the Middle Section being a part of the original construction or later modification, because of its itakura construction. A recent scientific examination on the timbers (dendrochronology) suggests that the repository is most likely to have been built in the middle of the eighth century, contemporary with the offered treasures, and its construction unchanged from the original.
In 1997, the Shosoin Repository was designated as a National Treasure. In the following year, it was registered into a World Heritage as a part of Historic Monuments of Ancient Nara.
West Repository and East Repository
At present, the treasures are no longer stored in the Shoso but in two repositories that were built in the twentieth century. These modern repositories are located in southwest and southeast of the Shoso, and are literally called West Repository and East Repository respectively. The West Repository was built in 1962, and the East Repository in 1953. Both repositories are made of reinforced concrete with structural steel, and climate-controlled by HVAC system. The West Repository accommodates the majority of the treasures, and is normally kept locked under imperial seal. In autumn, the repository becomes accessible for two months, and annual condition-check and examination on the treasures is carried out by the staff. The East Repository serves more as a temporary storage for those artifacts, mainly textiles, still under classification and conservation. The Shōgozō sutra handscrolls are now stored there too.
Shōgozō Sutra Repository
The Shōgozō was originally a repository of sutras for the sub-temple Sonshōin of the Todaiji, and located close to the Tegaimon gate. During the Meiji period, the sutras were offered to the Imperial Household, and at the same time the repository was dismantled and reconstructed within the grounds of the Shosoin. The contained sutras are old manuscripts of Buddhist scriptures ranging from those of Sui and Tang dynasties in China to Nara, Heian and Kamakura periods in Japan. These sutras are currently stored in the East Repository.