Ichirō Hatoyama (鳩山 一郎, Hatoyama Ichirō^?, January 1, 1883 – March 7, 1959) was a Japanese politician and the 52nd, 53rd and 54th Prime Minister of Japan, serving terms from December 10, 1954 through March 19, 1955, from then to November 22, 1955, and from then through December 23, 1956.

Ichirō Hatoyama was, as his name indicates, the firstborn boy. He was born into a wealthy cosmopolitan family in Tokyo. His father Kazuo Hatoyama (1856–1911) was a Yale graduate (and Speaker of the House of Representatives) and his mother Haruko Hatoyama (1863–1938) was a famous author and the founder of Kyoritsu Women's University.

Ichirō was a Master Mason and a Protestant Christian (Baptist). He was Japan's third postwar Christian Prime Minister.

Iichirō Hatoyama, Ichirō's only son, made a career for himself as a civil servant in the Budget Bureau of the Finance Ministry. Iichirō retired after having achieved the rank of administrative Vice Minister. In his second career in politics, he rose to become Foreign Minister of Japan in 1976–1977.

Yukio Hatoyama (鳩山 由紀夫, Hatoyama Yukio^?, born 11 February 1947) is a Japanese politician who served as Prime Minister of Japan between 16 September 2009 and 2 June 2010, and was the first ever Prime Minister from the modern Democratic Party of Japan.

First elected to the House of Representatives in 1986, Hatoyama became President of the DPJ, the main opposition party, in May 2009. He then led the party to victory in the August 2009 general election, defeating the long-governing Liberal Democratic Party (LDP). He represents the 9th district of Hokkaidō in the House of Representatives.

Hatoyama comes from a prominent Japanese political family which has been likened to the Kennedy family of the United States.

Hatoyama, who was born in Bunkyō, Tokyo, is a fourth generation politician. His paternal great-grandfather, Kazuo Hatoyama, was speaker of the House of Representatives of the Diet of Japan from 1896 to 1897 during the Meiji era. Kazuo later served as the president of Waseda University. His paternal great-grandmother, Haruko Hatoyama, was a co-founder of what is known today as Kyoritsu Women's University. His paternal grandfather, Ichirō Hatoyama, was a major politician; he served as Prime Minister and was a founder and the first President of the Liberal Democratic Party in 1956. As Prime Minister, he restored diplomatic relations with the Soviet Union, which cleared the way for Japan's membership in the United Nations.

Naoto Kan (菅 直人, Kan Naoto^?, born 10 October 1946) is a Japanese politician, and former Prime Minister of Japan. In June 2010, then-Finance Minister Kan was elected as the leader of the Democratic Party of Japan (DPJ) and designated Prime Minister by the Diet to succeed Yukio Hatoyama. On 26 August 2011, Kan announced his resignation. Yoshihiko Noda was formally appointed as Prime Minister on 2 September 2011.

Kan was born in Ube City, Yamaguchi Prefecture, as the son of Hisao Kan, an executive for a glass manufacturer. He graduated in 1970 from the Tokyo Institute of Technology and became a licensed benrishi (patent agent/attorney) in 1971.

His hobbies are go, shogi and origami. Kan built a machine to calculate the complicated mahjong point system and applied for a patent in 1973.

After graduating from university, Kan worked at a patent office for four years. He actively engaged in civic grassroots movements for years and also served on election campaign staff for Fusae Ichikawa, a women's rights activist.