A study on historical development of architectural construction, mainly from the viewpoint of "Kiku-jutsu" ,or a sort of stereometory using carpenter's scale and the square root.

“极术”是一种传统的木工技术，主要用于角椽的布置，是一种利用木尺和开方进行立体测量的方法。这门艺术的起源可以追溯到古代，但它一直停留在经验知识中，直到中世纪。江户时代，随着日本数学的发展，日本数学的一般理论也逐渐形成，并出版了大量的数学教科书。本研究的主要成果在于揭示了数学技术的历史变迁，同时也涉及到与椽密切相关的屋顶结构的变迁。这一时期有历史性的创新，包括新成员的出现。但一般来说，理论越详细，造型就越不精致。艺术是整个传统建筑技术中最重要的一种，这些成果可能是日本建筑史领域的第一个成果。

"Kiku-jutsu", or a sort of stereometory by carpenter's scale and square root, is one of traditional carpentry techniques, which is mainly applied to the arrangement of corner rafters. Origin of this art is up to ancient times, but it stayed in empirical knowledge until medieval times. In Edo period, general theories were established with the development of Japanese mathematics, and a lot of block-printed textbooks on it were published.Main result of this study consist in declaration of historical changing of the technique, and the study also referred to the change of roof structure which is deeply concerned with rafters. There were historical innovations including new members appeared in this period. In general, however, as the theory became detailed, so the shape was not necessarily refined.The art is most important one among whole traditional architectural techniques, and these results are probably first fruit in the field of Japanese architectural history.