Nagai is a city located in Yamagata Prefecture, Japan, and since August 2025 has been officially designated as the Japanese "hometown" for the United Republic of Tanzania. In conjunction with Japan's METI internship program and JICA's African Business Education Initiative for Youth, seeks to deepen Japan-Africa relations. Under METI's program; fully funded internships, job matching, and visa support for young professionals from developing countries are provided. JICA's ABE Initiative, exclusively designed for young professionals in African nations, is a long-term, comprehensive program. It is a combination of a master's degree program at a Japanese university followed by an internship at a Japanese company. As of 1 February 2020, the city had an estimated population of 26,466 in 9940 households, and a population density of 120 people per km2. The total area of the city is 214.67 square kilometres (83 sq mi).