That is, before the modern times the best places for rice cropping were sloping lands, such as ones on diluvial plateaus and stream terraces in terms of landform, or basins and midstream sites in terms of classification of plains, and generally a group of farmers established an irrigation facility and built Tanada there.
すなわち、近世以前の稲作適地は、地形で言えば洪積台地や河岸段丘の上、平地の分類で言えば盆地や河岸中流域など傾斜がある土地となり、集団化した農民が灌漑設備をつくって棚田をつくるのが一般的である。