Shimōsa Plateau
In the period immediately following World War II the plateau remained agricultural. Primary industry, almost entirely agriculture, accounted for 63% of economic activity, secondary accounted for 12%, and tertiary 25%. Post-war industrial planning resulted in large-scale development of coastal areas on the eastern Shimōsa Plateau along Tokyo Bay. Fishing and agricultural areas along the bay were replaced by landfill. The scenery of the eastern plateau went from largely agricultural to a vast area of factory smokestacks and high-rise housing. The development of sprawling port facilities, originally centered on the city of Chiba, culminated in the establishment of Keiyō Industrial Zone. Manufacturing facilities were developed across the central Shimōsa Plateau in the same period.