Junya Koizumi (小泉 純也, Koizumi Jun'ya; né Samejima (鮫島), January 24, 1904 – August 10, 1969) was a Japanese politician who served as Director General of the Japan Defense Agency during the 1960s. He is the father of Prime Minister Junichiro Koizumi and the grandfather of Japan Defense Minister incumbent Shinjirou Koizumi.
Source: “Jun'ya Koizumi”, English Wikipedia (CC BY-SA 4.0), excerpt