Final answer:
Japan's main urban concentrations consist of the core area, the Kansai District, and the Tokyo metropolitan area. The Tokyo metropolitan area is the largest urban area in Japan with a population of over 38 million.
Step-by-step explanation:
Japan's main urban concentrations consist of three regions: the core area, the Kansai District, and the Tokyo metropolitan area.
The core area, which stretches from Tokyo to Nagasaki, is Japan's most urbanized region. According to the CIA World Factbook, the estimated population of Japan in 2017 was more than 126 million.
The Tokyo metropolitan area, located in the Kanto Plain, is the largest urban area in Japan with a population of more than 38 million. The Kansai District, which includes the cities of Kobe, Osaka, and Kyoto, is the second-largest urban area in Japan.