Two years later he joined the Imperial Japanese Army General Staff Office in Hiroshima where he served during the course of the First Sino-Japanese War.

He was then assigned to the staff of the Inspectorate General of Military Training and was appointed commandant of the Army's Toyama School in 1900.

[1] In 1918, Japan joined the Allies in a joint intervention into the Russian Civil War in support of the White movement.

Ōtani was appointed head of the Japanese expeditionary force with Yui Mitsue as the Chief of Staff.

[1] On 12 August, Japanese forces departed from Tokyo Station for Hiroshima, where they were to board ships destined for Vladivostok.

On 1 November 1920, Ōtani was awarded the Order of the Golden Kite for his role in World War I and the Siberian intervention.

Accomplishments: During his military career, Ōtani displayed strong leadership skills and a deep understanding of logistics and training.

One of Ōtani's most notable assignments was his leadership role in the Japanese expeditionary force during the Russian Civil War.

Working alongside Chief of Staff Yui Mitsue, Ōtani played a vital role in the Allied Siberian Intervention.

In recognition of his contributions during World War I and the Siberian intervention, Ōtani was awarded the Order of the Golden Kite on 1 November 1920.