The cultivation is carried out in the mountain areas or basins where the paddy soil is argilliferous, particularly in the valleys and basins between medium-sized mountains with their eastern and western sides wide and open, where the day temperature difference during the summer is more than 10ºC.
水田土壌は粘土質、地形は山間または盆地となっており、なかでも、東西に開けた中山間の谷あいや盆地では、夏季の気温の日較差は10℃以上に達する所である。