The Class D51 (D51形) is a type of 2-8-2 steam locomotive built by the Japanese Government Railways (JGR), the Japanese National Railways (JNR), and Kawasaki Heavy Industries Rolling Stock Company, Kisha Seizo, Hitachi, Nippon Sharyo, Mitsubishi, and Mitsubishi Heavy Industries from 1936 to 1945 and 1950 to 1951. 174 units are in preservation in Japan, including five operational examples. A further 13 are preserved in Russia and Taiwan, bringing the total number of preserved units to 187.