On the recommendation of a fortune-teller, he decided to become a writer. He sent the second draft of his first detective story, the Tattoo Murder Case, to the great mystery writer Edogawa Ranpo, who recognized his skill and who recommended it to a publisher. It was published in 1948.
He received the Tantei sakka club sho (Mystery Writer Club Award) for his second novel, the Noh Mask Murder Case in 1950.
Takagi was a self-taught legal expert and the heroes in most of his books were usually prosecutors or police detectives, although the protagonist in his first stories was Kyosuke Kamizu, an assistant professor at Tokyo University.
In The Informer (1965), a former Tokyo stock exchange worker who is fired because of illegal trades. A subsequent stock market crash means that he has no hope of returning to his old career and therefore he accepts a job from an old friend even though he eventually discovers that the new firm he works for is really an agency for industrial espionage. The plot is based on actual events.
He was struck by stroke several times since 1979, and died in 1995.
Wipo Publishes Patent of Kabushiki Kaisha Yakult Honsha for "Medicinal Agent Comprising Thiazolidine Derivative or Salt Thereof as Active Ingredient" (Japanese Inventors)
Apr 13, 2013; GENEVA, April 13 -- Publication No. WO/2013/051672 was published on April 11.Title of the invention: "MEDICINAL AGENT COMPRISING...