As a schoolgirl in Kobe, Otsuji was an Asian Junior karate champion, then later enrolled at Seoul National University to study Korean and taekwondo.

As Otsuji did not run in the 2013 House of Councillors election, she left office at the end of the term in July.

[2]In 2019, as the Executive Director of the Project Team on SOGI of the Constitutional Democratic Party of Japan, Otsuji legislated same-sex marriage.

In August 2005, Otsuji published an autobiography Coming Out: A Journey to Find My True Self (カミングアウト～自分らしさを見つける旅, Kamingu auto - Jibun rashisa o mitsukeru tabi), and in doing so came out as Japan's first lesbian politician, the day before 2005 Tokyo Pride.

Since same-sex marriages are not recognised under Japanese law, gay couples in Osaka had previously found it impossible to rent public housing.

In June 2007, Otsuji held a public wedding ceremony in Nagoya with her partner Maki Kimura, although same-sex marriages are not legally recognised in Japan.

Her first term in the Osaka Assembly expired on April 29, 2007, but in July 2007 she appeared on the official candidate list of the Democratic Party of Japan, becoming the first-ever openly homosexual serious contender for election to the National Diet.