Koizumi Matajirō

The Koizumi family, as a model of political aristocracy in Japan, has had members active on the political stage for over a hundred years. The family's political tradition began during the Meiji era, founded by the family's progenitor, Koizumi Yohei. He lived around Yokosuka Harbor and actively participated in government-led military expansion, especially in developing naval forces. To support the government's military-industrial efforts, Koizumi Yohei organized workers to become an important part of the industrial chain serving the government, accumulating initial wealth through this.

His son, Koizumi Jiro, was born into the family business and became the heir. He displayed a strong desire to join the military, but his plans were thwarted by opposition within the family. Nevertheless, he later entered politics, joining the Rikken Kaishintō (Constitutional Reform Party). Relying on family funds and personal effort, he gradually made his way onto the political stage. In 1908, he was elected as a member of the House of Representatives, becoming the family's first representative in the Japanese Parliament. This historic event marked the solidification of the Koizumi family's position in Japanese politics. Subsequently, he was active in opposing the signing of the Treaty of Portsmouth (which ended the Russo-Japanese War), participated in the Second Imperial Constitution Movement, and served as Vice Speaker of the Diet in 1924. He held important positions within the Rikken Minseitō (Constitutional Democratic Party) until 1937, during which time he witnessed the gradual strengthening of fascist military power under the authorities, leading to decreased political activity during World War II.

Koizumi Jiro's private life also drew attention: at age 30, he married Geisha Ayabe Naoko, and he had concubines. His son, Junichiro Koizumi, was his eldest son. His mother, Yoshie Koizumi, came from a relatively ordinary family, which helped ensure the continuity of the family's political influence. Yoshie Koizumi was enthusiastic about finding suitable matches for her daughter, ultimately facilitating her marriage to Shakujima Junya. Shakujima Junya, coming from a poor background, worked hard to become a member of the Rikken Minseitō and was elected to the House of Representatives at age 32, marrying into the Koizumi family and adopting the name Koizumi Junya.

Koizumi Junya gradually emerged in politics, serving as the Minister of Defense and becoming a well-known hawkish politician. However, his political career was cut short in 1965 after an attack by Socialist Party members in the Diet. In his later years, he suffered from mental illness, leading a turbulent life. After his death, the family’s political baton was gradually passed to their second son, Junichiro Koizumi. He inherited the family tradition and continued to exert influence in Japanese politics. In 1951, Koizumi Jiro passed away, marking the rise of a new generation of leaders and suggesting that the family’s significant role in Japan's political landscape would continue to be inherited.