Abstract
Okinawa and China, situated near the 25° North Latitude of the East China Sea, have had mutual exchanges since the mid-14th century via Foochow. Ryukyu in those days was under the control of the Satsuma clan and within reach of Japanese culture. However, it seems to have had strong influence from Chinese culture as well. The purpose of this study is to find Okinawa's uniqueness in housing through comparative study based on a survey of folk houses on the west side of Taiwan and in Fukien Province of China, both of which are at the same latitude as Okinawa. As to space composition of folk houses in Okinawa, which has Chinese and Japanese cultural influences in its history, similarity, difference and regional distinction are comparatively studied with the areas mentioned above. Weather in Okinawa and Taiwan, almost situated at 25° North Latitude, is severe, i.e., high temperature and humidity throughout the year, strong insulation from the vertical sun in summer, strong seasonal wind and short sunshine duration in winter. In addition, typhoons are frequent in both areas. Therefore, it is inevitable to both areas to make protective preparation for the scorching heat of summer, typhoons from autumn to winter and the cold of winter with strong wind. So far, the survey of seventeen folk houses throughout six islands and prefectures shows that indoor thermo-conditions of folk houses in Okinawa duplicate the outside air and that in Taiwan is obtained by shutting it out. In other words, Okinawa's housing priority is space composition for summer and Taiwan's for winter. The roof is laid thickly with almost the same unglazed red tiles both in Okinawa and Taiwan. It is highly adiabatic and provides strong insulation against the heat in summer. However, materials and the method of construction of the wall body are quite different in those two areas. In Okinawa it is a lumber framed wall, in Taiwan it is a masonry construction. According to the difference of the wall body, distinction of the opening ratio and heat transmission resistance of the wall body make the difference of indoor thermo-conditions mentioned above. Since the roof weight of Okinawa's folk house with a light framed wall is not sufficient to prevent the building itself being lifted up by the blast at the time of typhoon, the row of trees, the kind that is highly efficient to prevent wind, came to be arranged around the site in order to reduce strength of wind. That is, a substantial roof of red tiles and a windbreak of Okinawa's folk houses has been absolutely necessary to realize a dwelling space which conforms to weather condition in Okinawa. It is Okinawa's unique space composition which cannot be seen at the same latitude in the East China Sea area.
