Tōkai Village, located in Naka District, Ibaraki Prefecture, Japan, is the second most populous village in the country after Yomitan Village in Okinawa and ranks fourth in population density among all village-level administrative divisions in Japan. Although it meets the criteria to be designated as a "town" under Ibaraki Prefecture regulations, Tōkai Village retains its status as a "village" and is one of only two such entities remaining in the prefecture (the other being Miho Village in Inashiki District).
According to the 2021 Ibaraki Livability Rankings, Tōkai Village placed second, reflecting its excellent living environment and quality of life.
Tōkai is also recognized as the birthplace of Japan’s nuclear energy development. In 1957, the Japan Atomic Energy Research Institute (now Japan Atomic Energy Agency) established the Tōkai Research Institute in the village, and Japan’s first nuclear reactor, JRR-1, achieved criticality there. Since then, numerous nuclear-related facilities, including the Tōkai Power Station and Tōkai Daini Nuclear Power Plant operated by Japan Atomic Power Company, have been established, making the village a core part of the country’s nuclear industry along the Pacific coast.
However, on September 30, 1999, a criticality accident occurred at a private company, JCO, in the village. The incident resulted in the deaths of two workers and had a profound impact on the community and the nation, prompting renewed discussions in Japan regarding nuclear safety and management systems.
