He was the foster father of the Japanese spy Kawashima Yoshiko, who was the biological daughter of the Manchu Prince Su Shanqi.

After the Japanese victory he worked for the Government-General of Taiwan, before returning to Japan in 1897 to serve as a Chinese teacher at the Army Academy and Tokyo Higher Normal School.

[3] After the 1911 Revolution and the abdication of the Xuantong Emperor in 1912, Kawashima helped Prince Su and his family flee to Port Arthur in the Kwantung Leased Territory.

Kawashima and Prince Su envisioned a plan in which an uprising would establish an independent Manchu-Mongol state under the Qing dynasty with Japanese support.

With the tacit approval of the cabinet, the Army General Staff supported the activities of Kawashima in order to undermine Yuan.

The cause received funds from the businessman Ōkura Kihachirō among others, which were used to supply Babojab's army and to raise additional forces under Prince Su, consisting of Qing loyalists, Japanese volunteers and mercenary brigands.

[12] In 1925, Kawashima's foster daughter Yoshiko shaved her hair and began wearing male clothes, declaring her intention to "cease being a woman."