At that time, dikes and mounds of Tanada were made of stone walls which could bear steepness of the slope, for the purpose of increasing yield to the maximum.
その際、少しでも収量を増やすため、棚田の畔（あぜ）や土手（どて）の部分（土坡、どは）は、極限まで収量を上げるために急な傾斜に耐えられる石垣でつくられた。