The West Shosoin (The West Treasure House)
Copper mirrors that were similar to those stored in Nara Shosoin (The Imperial Treasure House) were found at Nango-mura village in Miyazaki Prefecture. In order to preserve and exhibit the mirrors, The West Shosoin was built as a reproduction of the Nara Shosoin, which has survived throughout the ages for over 1,200 years. This work was true to the original and utilized the same kinds of timbers, roofing tiles, fixtures and fittings including even the nails.
The Shosoin is a traditional log house with a raised floor. The total volume of wood required for the construction was over 700m3, a total of 800 individual timbers, each with a diameter of 50 to 60cm. In order to keep faith with the original tradition of construction it was essential to find a source of appropriate wood a time consuming search that finally ended with the identification of Kiso Hinoki wood, a Japanese cypress grown in the Kiso region. Following on from this, and again in keeping with traditional methods, a number of ceremonies were recreated and performed such as the Okibiki Shiki, where the timbers were paraded through the villages, Chona Hajime Shiki, which is a ceremony to celebrate the commencement of work on the wood, and Joryo No Gi, a ceremony for performance of the land survey.
A total of 40,000 tiles were used in construction of the massive overhanging roof, which has a complicated formation of members and weighs in at 280 tons. In order to achieve the beautiful sprocket curve lines, that matched the original design, a series of precise calculation were made through three dimensional space frame analysis for the transformation values of each roof member.
Our experience with constructing the West Shosoin shows that the wisdom and ingenuity of our forefathers, who lived more than 1,200 years ago and who did not enjoy the luxury of modern tools or three dimensional space frame analysis, has been successfully passed down to our generation.