Iwasawa was born in Shinshuku-mura, a town near Kiryū, in Gunma Prefecture.
[1] From 1937 to 1940 Iwasawa studied as an undergraduate at the University of Tokyo, after which he entered graduate school at the same institution and became an assistant in the Department of Mathematics.
[1] However, this same year Iwasawa became sick with pleurisy, and was unable to return to his position at the university until April 1947.
[1] In 1950, Iwasawa was invited to Cambridge, Massachusetts to give a lecture at the International Congress of Mathematicians on his method to study Dedekind zeta functions using integration over ideles and duality of adeles; this method was also independently obtained by John Tate and is sometimes called Iwasawa–Tate theory.
[2] Among Iwasawa's most famous students are Robert F. Coleman, Bruce Ferrero, Ralph Greenberg, Gustave Solomon, Larry Washington, and Eugene M.