Dee ihe na-aga n'ihu maka paragraf a - Na 1900, Ōkubo e buliri ya n'ọkwa lieutenant general na onye isi ndị ọrụ nke General Inspectorate of Military Training. Na Mee 1902, ọ ghọrọ onye isi nke IJA 6th Infantry Division. N'oge Agha Russo-Japanese, IJA 6th Infantry Division so ndị agha nke abụọ nke Japan, mana mgbe Agha nke Shaho gasịrị
A kpọfere ya na ndị agha nke anọ nke ndị Japan tupu Agha Mukden. Mgbe agha ahụ gasịrị, e nyere ya Order nke Rising Sun, klas nke 1 na Order nke Golden Kite, klas nke 2. N'ọnwa Julaị afọ 1906, e zigara ya ka ọ chịwa ngalaba nke atọ nke IJA ma na Septemba afọ 1907, e buliri ya n'ọkwa "kazoku" na aha "danshaku" (baron).