Student activism
Ishii graduated from Chuo University, where he studied the legal educations and the graduate school of Waseda University. During the student time, he has participated in Student activism. Ishii lived in the Soviet Union for 6 years as an international student to Lomonosov Moscow State University, following the recommendation by Yasushi Akutagawa, Representative of Japan-Soviet Union Youth Friendship Committee at that time. There he majored theory of state and law under the guidance of Professor A. Y. Denisov and earned a doctorate in philosophy.