In 1887 he became chief of staff of the Tokyo Garrison and following the reorganization of the Imperial Japanese Army under the advice of Prussian military advisor Jakob Meckel, he became chief of staff of the IJA 1st Division.
Amami Ōshima | Nagisa Oshima | Yuko Oshima | Oshima Shipbuilding | 5592 Oshima | Ōshima Yoshimasa | Naoto Ōshima | Heinouchi Yoshimasa |
Charged with implementing the Imperial Japanese Army's commission from new Korean government to expel the Chinese Beiyang Army from Korean territory by force, a detachment of the Japanese First Army consisting of 4000 men under command of Major General Ōshima Yoshimasa marched south from Seoul towards the major port city of Asan.