The Type 89B I-Go Otsu (In Kanji 八九式中戦車 乙型 , "Hachikyū-Shiki Chū-Sensha I-Gō Otsu") was a Japanese medium tank that fought primarily in China before World War II, and the first mass-produced tank in the world with a diesel engine. In the anime, it was first seen during a flash-forward in Episode 1, then appeared in Episode 2.