This system was introduced in order to protect historic cities, towns and villages in Japan. It enables municipalities to designate “Preservation Districts for Groups of Traditional Buildings.” Among the Preservation Districts, those of national significance are classified as “Important Preservation Districts for Groups of Traditional Buildings” by the national government upon receiving an application from a municipal government.
As of 15 December 2023, 127 districts in 105 municipalities are classified as Important Preservation Districts for Groups of Traditional Buildings, which contain about 30,250 traditional buildings designated as traditional buildings or environmental properties. (Agency for Cultural Affairs)

It is ideal for touching old houses and townscapes because there are many traditional Japanese houses remaining.