Journalist Takashi Tachibana, whom many in his field would rank as the best of his era in Japan, died of acute coronary syndrome on April 30, his family said Wednesday. He was 80.

Tachibana became famous nearly five decades ago thanks to a widely publicized investigative reporting project. Then, like the Washington Post’s Bob Woodward after Watergate, the frizzy-haired reporter refused to rest on his laurels. He continued for decades to produce leading-edge journalism, scholarship and criticism.

Tachibana’s leadership of monthly magazine Bungei Shunju’s project, which involved relentless investigative digging into open sources, is often credited with having played a major role in bringing down the late Prime Minister Kakuei Tanaka, Japan’s most powerful leader in the postwar era, who was convicted over his involvement in the Lockheed bribery scandal.