Abstract
1. A shallow bashin-like topography (“ Waju-chikei”): The three rivers, that is, the Kiso, the Nagara and the Ibi run reticulately at their lower courses. The residents around those rivers have constructed the embankments in a circular form, talking advantage of natural levees. As at the center of each protected low land is a back marsh, it makes a shallow basin-like topography. The writer gives a name to this unique topography “Waju-chikei” (encircled topography). Its soil is a fine one. As the rivers deposit their silts in the restricted foreland, so the level of a latex closed land is higher than that of a formerly closed one.
2. Sequence of its land utilization: Every paddy-field in the back marsh had once been cultivated, but as the time passed by the level of the encircled topography became so low compared with that of the foreland, that it could not drain water at all. Therefore the residents were obliged to construct a canal for draining, and laid the soil obtained from it upon another paddy-field. It was done about 1840 A. D.. But unfortunately the productivity of the paddy-field could not be recoverd. In the Meiji period, however, the three rivers were separated, and with the in vention of a draining machine, the productivity of the back marsh field came to be fully displayed and the canals were gradually reclaimed. Even at present time its topography still has some effect upon the land utilization of this district.
