Kammala jumla mai zuwa: An daukaka shi zuwa Manjo a 1903, Shirakawa ya dawo ya yi umurni da IJA 21st Infantry Regiment a lokacin Yaƙin Russo-Japan. A lokacin yakin, an canja shi zuwa ma'aikatan IJA na 13th Division. An ba wannan sashen aikin da ba shi da izini na
mamaye Sakhalin kafin kammala Yarjejeniyar Portsmouth, sauka a Sakhalin a ranar 7 ga Yuli, 1905, watanni uku kawai bayan an kafa shi, kuma ya tabbatar da tsibirin a ranar 1 ga Agusta, 1905. Sakamakon nasarar aikinsa, an ba Japan kyautar kudancin Karafuto a lokacin Yarjejeniyar Portsmouth, ɗayan ƙananan nasarorin ƙasar Japan a lokacin yaƙin. Bayan yakin, an sanya Shirakawa zuwa Ofishin Ma'aikata na Ma'aikatar Sojoji daga Oktoba 1905. An ba shi mukamin Laftanar Kanal a 1907, Kanal a 1909, kuma kwamandan rundunar sojojin IJA ta 34.