After studying at Meirinkan, he graduated from the Imperial Military Academy in 1878 and from the Army War College in 1885 as a first class student.

As a result, this operation had a great influence on the cession of southern Sakhalin in the Treaty of Portsmouth.

He taught students from the Qing dynasty, and Chiang Kai-shek, who later became President of the Republic of China, looked up to him as his teacher.

Gaishi Nagaoka Died of a bladder tumour at Keio University Hospital in 1933.

[2] There is a statue of Nagaoka and a foreign history park honouring him in the national lodging house in Oshiro on Kasado Island, in Kudamatsu, Yamaguchi.