It is observed that the urban compositions of pre-modern Japanese Castle Towns were built in harmony with rich diversities in Nature. This research is done by analysing the urban planning of the middle age cities built by Nanbu Clan.
These Nanbu cities appeared with unobstructed views of the sacred mountains; the town installations were placed on the concentric circle line in which the Iwakura Rock appeared as the concentric centre. These castle towns in Nanbu Region in Tohoku are believed to be planned in symbiosis with Nature; yet, the exact motivation behind such planning phenomenon is not scientifically evident and justifiable. In order to, thus, discover their planning intensions, these worshipping objects in the Region shall be listed, and their relations with the urban compositions may be objectively tackled and grasped.
This research is based on the hypothesis that the town distributions were planned to correspond with the sacred mountains and Iwakura Rocks in the region; it concerns itself with how the urban planning of Morioka and Hachinohe, both pre-modern castle towns built by Sannohe-Nanbu the head house, were affected by the following three aspects: 1) the street composition as the urban framework, 2) the deployment of major facilities, and 3) the locations of Nanbu Clan temples. This investigation is verified by means of GIS.
First, the city main streets that set up the urban framework may be classified into two types: the axis and the fluctuation with the vista to the mountains. From the axis type of main street and the main portion of the fluctuation type of main street as well, the object mountain appears with unobstructed view of sacred mountain top. All the side streets are either parallel or perpendicular to either type of main street. In Morioka Castle Town, the Eboshiiwa Iwakura the worshipping object is located on the intersection point where the extension line of the Ohte Street, the highway that links the castle gate, meets the extension line of the Ohshu main street. Both Ohte and Ohshu intersect each other in 60° of angle.
Second, this paper tackles the special phenomenon of Morioka castle town, treating the sacred Iwakura Rock as the centre of the concentric circle on which the major installations were placed on the circumference; further, from the northeast angle of the Iwakura, the temples that guards the northeast Demon's gate was built; moreover, a castle gate was built near the Iwakura and the moat was constructed with the bended portion to be adjacent to the Iwakura. All these are verified.
Third, these areas that were built with the high-ranked temples which were related with Nanbu Clan are studied; this research tries to verify the vista from the town streets and the entrance paths of the temples that were related to Nanbu-daimyō to the sacred object mountains like Mount Nansho and Mount Hayachine.
Basing on the above, the specific interrelation between the urban compositions of pre-modern castle towns and the religious objects in the regions of Nanbu Sovereign could be manifested. Since the Middle Age, the Nanbu Clan has ruled the Nanbu Region and bonded to the aboriginal culture in the Tohoku of Japan; their urban planning of town distribution were processed with respect to their religious objects － Sacred Mountains and Iwakura Rocks － can be reasonably verified.
