As rice cultivation has become more massive and mechanized since the end of the World War II, agricultural fields, each of which used to be shaped differently according to the slope, were improved and unified into large rectangles in which it is easier to introduce farm machines.
戦後は稲作の大規模化・機械化が推し進められ、傾斜に合わせて様々な形をしていた圃場は、農業機械が導入し易い大型の長方形に統一されて整備された。