In the pre-war period it was natural that suits were tailored. Everyone was taking it for granted the process of "going to a tailor and choose a fabric, have the measurements taken, have a fitting, then have the craftsmen sew it by hands". In those days it was not for every avocation to wear business suits and the population that actually needed them was small so there was hardly a demand for high-volume production. Moreover, the quality of ready-to-wear suits was extremely low that the consumers assumed that "suits are tailored".
But everything has changed after the war. The number of businessmen has drastically increased with the rapid economic growth and the vast number of men started to wear suits as working clothes. In order to supply the growing demand, technology for high-volume production became an absolute necessity. Technology to manufacture ready-made clothes introduced from the United States made it possible for domestic apparel companies to establish their own technology for high-volume production. Since then, especially after suits were established completely as working clothes among businessmen, the quality of fabrication techniques for ready-to-wear suits has advanced. More businessmen started to "go shopping" to department stores or specialized shops and pick the one to suit their own size and taste from the bulk produced ready-to-wear business suits.