Takaaki Yoshimoto, a noted literary critic and the father of popular writer Banana Yoshimoto, died early Friday of pneumonia at a Tokyo hospital, his family said. He was 87.

Yoshimoto was a vocal critic of established leftwing movements and offered theoretical support to young activists in the struggle over the Japan-U.S. security treaty in 1960.

Graduating in 1947 from Tokyo Institute of Technology, Yoshimoto worked at a midsize company but lost his job because of his union activities. First coming to attention as a poet, he later pursued the wartime responsibility of literary figures prominent during and after the war.

He launched a magazine with renowned poet Gan Tanigawa and others, exploring themes such as nation-states and the family, before establishing a reputation as a giant of postwar thought.

In the 1980s, Yoshimoto published works on subcultures, dealing with subjects such as rock music, manga and fashion. Offering sharp commentary on contemporary issues, he was critical of antinuclear movements.

Also deeply interested in religion, Yoshimoto discussed faith in his works, including writing about Aum Shinrikyo, the cult that carried out the 1995 Tokyo subway nerve gas attack. With his sharp critiques and humble character, he became a charismatic figure with great influence, receiving a number of prestigious literary awards in his later years.

Yoshimoto had been fighting pneumonia since being hospitalized in January.

His eldest daughter, Yoiko Haruno, is a manga artist. Banana is his second daughter.

Yoshimoto suffered serious health problems after a swimming accident in 1996, but he continued to work while fighting his illness. He voiced opinions on science, technology and nuclear power after last year's earthquake and tsunami disasters. He reportedly continued to be supportive of reactors due to his belief in the progress of science.