Japan is organized into 47 prefectures grouped into eight traditional regions stretching from Hokkaido in the north to Okinawa in the south, forming a volcanic archipelago of more than 3,000 islands in the Pacific Ocean. Tokyo is the most populous metropolitan prefecture, with more than 14 million inhabitants, and its metropolitan area is the largest in the world, with more than 37 million people. The country is highly seismic, with risk maps identifying areas vulnerable to liquefaction, tsunamis, and typhoons, especially in Kyushu and Okinawa. The eight regions are Hokkaido, Tohoku, Kanto, Chubu, Kinki, Chugoku, Shikoku, and Kyushu-Okinawa, each with distinct geographical and economic characteristics. In this Risk, Honshu is the central island connecting north and south and concentrating most of the population and industry, Hokkaido is the northern flank with access to Russia, Kyushu and Okinawa are gateways toward Korea, China, and the southern Pacific, and the Seto Inland Sea is a vital maritime route connecting the Sea of Japan with the Pacific. Controlling the Tokyo-Osaka-Nagoya corridor gives you the country´s economic axis, while whoever dominates the Tsushima and Tsugaru straits controls the main maritime approaches.