In Japan after World War I, the population of the big cities increased with the growth of the heavy and chemical industries in urban areas, resulting in a widening of gaps in regional development. During the 1930s, the government urged factories to relocate from the cities in order to narrow the gaps. Moreover, the government assisted in the evacuation of munitions factories, above all the strategically important machine shops, to avoid air strikes during the Pacific War.
Although not as many machine shops dispersed geographically as the government had anticipated, the agglomeration of small-to-medium-sized machine shops did accelerate, and the experience of learning by making various types of machines was acquired by many local cities as a result. Machine production increased remarkably in these local cities after World War II, enabling regional small-to-medium-sized shops to contribute substantially to the Era of the High-Speed Growth in the 1960s.
