After the Xinhai Revolution overthrew the Qing dynasty in 1912, Xianyu was given up for adoption in 1915 at the age of eight to her father's friend, Naniwa Kawashima, a Japanese espionage agent and mercenary adventurer.

Earlier that day, she had dressed in a kimono with a traditional female hair style and took a photo among blooming cosmos to commemorate "my farewell to life as a woman."

A photo of the transformation appeared five days later in the Asahi Shimbun under the headline: "Kawashima Yoshiko's Beautiful Black Hair Completely Cut Off - Because of Unfounded 'Rumors,' Makes Firm Decision to Become a Man - Touching Secret Tale of Her Shooting Herself", alluding to a prior episode in which she had shot herself in the chest with a pistol given to her by Iwata Ainosuke [ja].

[2] Kawashima explained in another article two days after the first that "I was born with what the doctors call a tendency toward the third sex, and so I cannot pursue an ordinary woman's goals in life...

[1] In November 1927 at age 20, her brother and adoptive father arranged for her marriage in Port Arthur (also known as Ryojun) to Ganjuurjab, the son of Inner Mongolian Army general Babojab, who once led the Mongolian-Manchurian Independence Movement there in 1911.

She left Mongolia, and she first traveled to teeming coastal towns of China and lived a bohemian lifestyle for some years in Tokyo with a series of rich lovers, both men and women.

[4] While in Shanghai, she met Japanese military attaché and intelligence officer Ryukichi Tanaka, who utilised her contacts with the Manchu and Mongol nobility to expand her network.

[5][6] Kawashima was well-acquainted with Puyi, the last emperor of the Qing dynasty, who regarded her as a member of the imperial family and welcomed her into his household during her stay in Tianjin.

It was through this close liaison that Kawashima was able to persuade Puyi to become a figurehead ruler for Manchukuo, a puppet state created by the Japanese in Manchuria.

However, her very popularity created issues with the Kwantung Army because her utility as an intelligence asset was long gone, and her value as a propaganda symbol was compromised by her increasingly critical tone against the Japanese military's exploitative policies in Manchukuo as a base of operations against China in the Second Sino-Japanese War, and she gradually faded from public sight.

The court rejected the defence's bid to have her tried as a war criminal rather than as a domestic traitor, based on a combination of jus sanguinis and Kawashima's failure to formally renounce her citizenship through China's Department of Civil Affairs.

[7] Charged with treason as a hanjian on 20 October 1947, she was executed by a bullet shot into the back of her head on 25 March 1948,[10] and her body was later put on public display.