Koichi Kato (加藤 紘一, Katō Kōichi, 17 June 1939 – 9 September 2016) was a Japanese politician of the Liberal Democratic Party who held a seat in the House of Representatives in the National Diet for 13 terms between 1972 and 2012.

[1] Kato was elected to several districts in Yamagata Prefecture and served as the Director-General of the Japan Defense Agency from 1984 to 1986 and Chief Cabinet Secretary from 1991 to 1992.

Kato was a leading member of the Kōchikai faction of the LDP aligned with Prime Ministers Masayoshi Ōhira, Zenkō Suzuki, and Kiichi Miyazawa.

After graduating from the University of Tokyo, Kato joined the Foreign Ministry in 1963, which led to stints at the Japanese embassies in Taipei and Washington, D.C.

In May 2000, upon the sudden illness and death of Prime Minister Keizō Obuchi, Kato did not make a challenge for leadership of the LDP, believing that internal strife would not be healthy for a party in mourning.

After consulting with the opposition parties, Kato realized that with support of his and Yamasaki's factions, a vote of no-confidence against Mori would pass in the Diet.

Nonaka launched a harsh round of party discipline, threatening to expel any LDP members that voted against Mori, and his threats had the desired effect: Kato's support dried up even within his own faction.

In November 2003, Kato made his return to the Diet as an independent, having retreated from politics long enough for the scandal to die down, and rejoined the LDP as a high-ranking member.

On 15 August 2006, Kato's adjoining house and office in Tsuruoka burned to the ground on the 61st anniversary of the surrender of Japan in World War II.

Reportedly the suspect was affiliated with a far-right organization and set fire to Kato's house for making remarks critical of then-Prime Minister Junichiro Koizumi visiting the Yasukuni Shrine.

Kato retired from political office after losing his seat for Yamagata 3rd district at the December 2012 general election to Juichi Abe, an independent and mayor of Sakata.