Nyora kupfuurira kweiyi ndima - Muna 1900, Ōkubo akasimudzirwa kuva lieutenant general uye mukuru-wevashandi veGeneral Inspectorate yeMasoja Kudzidziswa. Muna May 1902, akava mutungamiri weIJA 6th Infantry Division. Munguva yeHondo yeRusso-Japanese, IJA 6th Infantry Division yakasungirirwa kuJapan Second Army, asi mushure meHondo yeShaho
yakatamiswa kuJapan Fourth Army pamberi peHondo yeMukden. Pashure pehondo, akapiwa Order of the Rising Sun, 1st class uye Order of the Golden Kite, 2nd class. Muna Chikunguru 1906, akachinjirwa kutungamira IJA 3rd Division uye munaGunyana 1907 akasimudzirwa ku "kazoku" peerage aine zita rekuti "danshaku" (baron).