This paper aims to grasp the framing systems in Japanese traditional timber houses. According to the transfer routes of roof load, diversities of directions and the number of supporting members are defined. Ranking the arrangement of transfer routes whether in the core structure or in the outer structure hierarchically, various reasons of the more or less of supporting members are clarified as compared with the. displacement through the framework. Analyzing the composition of transfer routes for each house, it's revealed that the characteristics of framing systems are determined by two factors ; one is the potential of spatial expansion between core and outer structure, the other is the complication of framing formation such as piles of beams, girders and posts.
