Nakano is a special ward in the Tokyo Metropolis in Japan. The English translation of its Japanese self-designation is Nakano City. As of Ma…Nakano is a special ward in the Tokyo Metropolis in Japan. The English translation of its Japanese self-designation is Nakano City. As of May 1, 2015, the ward has an estimated population of 322,731, and a population density of 20,701 persons per km². The total area is 15.59 km². Nakano is the most densely populated city in Japan.