Geography of Kawanishi
Kawanishi means ‘west side of the river’. It is the name of a town on the Shibumi River, a tributary of Japan’s longest river, the Shinano. Vast rice fields, irrigated by the river, lie to the east. By contrast, the west side of Kawanishi offers a more complicated topography, with the restless meanders of the Shibumi River cutting deep into the narrow mountain valley. The mountains are formed of layers of sandy clay of different densities.The instability of this clay base, combined with the steepness of the topography and the force of the snow, continuously reshapes the fragile land surface. Each spring, as the snow melts,geotectonic fault lines and folding patterns are revealed.
Cultivation along the Shibumi
Running along the steep valleys are a series of terraced rice fields.Traditionally the cultivation of the land entailed a continuous negotiation with the behaviour of the river and the forces of snow and landslides. The method known as segai is a way of producing a flat piece of land by manipulating the course of the winding river by carving out a bypass for the water through the hills. In another technique, called mabu, small tunnels are carved out by the farmers. Mabu involves constructing an irrigation system, manipulating a small stream of water and forming terraced fields by artificially creating landslides and sedimentation on the sides of the valley.