Former Liberal Democratic Party kingmaker Mikio Aoki died Sunday. He was 89.

Aoki, known as the “don of the Upper House” for his influence inside and outside the LDP, served as a lawmaker in the chamber between 1986 and 2010. He began his political career as a secretary to Noboru Takeshita, who later became prime minister, and went on to serve as a prefectural assembly member in Shimane Prefecture, where Takeshita hailed from, before entering national politics.

“Aoki earned the trust of those beyond the ruling and opposition parties. I respect his stance of valuing that trust in his work as a politician,” Chief Cabinet Secretary Hirokazu Matsuno told a news conference Monday.