Mezue ahịrịokwu na-esonụ: N'ịbụ onye e buliri n'ọkwa onye isi n'afọ 1903, Shirakawa laghachiri ịchị IJA 21st Infantry Regiment n'oge Agha Russo-Japanese. N'oge agha ahụ, a kpọfere ya n'ụlọ ọrụ nke IJA 13th Division. E nyere ngalaba a ọrụ nke onwe ya nke
Na-achịkwa Sakhalin tupu mmechi nke Nkwekọrịta Portsmouth, na-agbadata na Sakhalin na 7 July 1905, naanị ọnwa atọ ka e guzobere ya, ma chebe agwaetiti ahụ site na 1 August 1905. N'ihi ihe ịga nke ọma nke ọrụ ya, e nyere Japan ndịda Karafuto n'oge Nkwekọrịta Portsmouth, otu n'ime uru ala ole na ole nke Japan n'oge agha. Mgbe agha ahụ gasịrị, e kenyere Shirakawa na Ngalaba Ndị Ọrụ nke Ministri Ndị Agha site na Ọktọba 1905. E buliri ya n'ọkwa lieutenant colonel na 1907, colonel na 1909, na onye isi nke IJA 34th Infantry Regiment.