[1] He was a leader of Freedom and People's Rights Movement (自由民権運動, jiyū minken undō) which would evolve into a political party.

Together with fellow Tosa samurai Sakamoto Ryōma, he was attracted by the radical pro-Imperial Sonnō jōi movement.

Jointly with Itagaki Taisuke, he submitted a memorandum calling for the establishment of a popularly elected parliament.

In 1874, together with Itagaki Taisuke, and Etō Shinpei and Soejima Taneomi of Hizen Province, he formed the Aikoku Kōtō (Public Party of Patriots), declaring, "We, the thirty millions of people in Japan are all equally endowed with certain definite rights, among which are those of enjoying and defending life and liberty, acquiring and possessing property, and obtaining a livelihood and pursuing happiness.

In 1881, he returned to politics, assisting Itagaki Taisuke found the Jiyūto (Liberal Party) which developed the daidō danketsu (coalition) movement in 1887.