On the day that Hidegorô Nakano became a research student, he went to his supervisor's office and applied for doctor degree by presenting his thesis which was already completed. Let me explain now the situation at that time. It was, of course, true that the doctorate was awarded only after a thesis had been submitted, examined and approved. But at that time it was common that a person was allowed to present their thesis only after they had been doing research for about 20 or 30 years and had reached a suitable age. But Nakano had just graduated from the university, and presented his thesis for a doctorate on the same day that he entered graduate school. This also astonished his supervisor, Professor Takuji Yoshie. After a while Nakano told me why he did so. The reason was that there was no age limit for presenting a doctoral thesis and, according to the regulations, there was no examination fee charged if a person was a student in the graduate school. But of course this was indeed a special case. Therefore, Professor Takuji Yoshie examined Nakano's thesis very carefully. He arrived at the conclusion that the author of the thesis was well qualified to be awarded the title of doctor. In 1936, Nakano was awarded doctor of science degree three years after submitting. At that year, he was 27 years old. This 27 year old doctor of science was reported many times in newspapers. The reason was that the people who got a doctorate were normally at least over 50 years of age at that time.

Nakano was helping with food for students, but this is difficult to understand without knowing the situation during April 1945 through March 1946 (the last year of the World War II). All educational institutions in Tokyo (kindergarten through university) were closed at the end of March 1945 and evacuated to safer regions. The Department of Mathematics of the Imperial University at Tokyo was evacuated to a local public school in the village of Osachi in the Suwa region of Nagano prefecture. Shortage of food was everywhere. Nakano often led his students on a hike hunting for food in neighbouring villages. In those cold mountain areas of poor soil a sack potatoes would be a harvest of the day. His wife invited the students to the temple where the Nakano family maintained a temporary residence and fed hungry students.

In the old education system of Japan prior to the end of World War II, graduate studies in Mathematics involved very little work of scheduled classroom lectures. Seminars were dominant. Much of the 3-year curricula for undergraduate mathematics majors was similar. Admission to the graduate programme was more like doctoral candidacy today. Regular members of Nakano's seminars, undergraduate as well as graduate, called themselves Nakano's students. Nakano moved to Hokkaido University from Tokyo University in 1952. Both universities were part of the system of the seven Imperial Universities, i.e., the only universities established and funded entirely by the central government of Japan. An appointment to a position from another institution of the system was regarded as transfer at the discretion of the president of an accepting institution. Nakano's appointment at Hokkaido University was thus a move from Tokyo to Hokkaido.

The Nakano Seminar existed from 1951 to 1959 while Hidegorô Nakano was an active faculty member of the Department of Mathematics at Hokkaido University. It was a group of graduate students engaged in research under Nakano's leadership. The group held a weekly seminar in the room next to his office on the third floor of Science Building where the Department of Mathematics was located. Doctoral degrees were conferred on most of them but some left the university without completing the degree requirements.

I am going to Canada, being invited by Canadian Mathematical Congress. I am scheduled to leave Sapporo 26 May, and to arrive at Vancouver 23 June. I shall stay in Kingston for about a year.

Hidegorô Nakano was suddenly hospitalised in Detroit on 27 August 1973, for a surgery of colon cancer. He experienced a series of complications after the surgery and continued to stay in the same hospital until he died on 11 March 1974.

I wrote a book, 'Set Theory', and submitted it to the American Mathematical Society to have it published in the Colloquium Series. However, it was rejected because of unfavourable reports from two referees. I also submitted it to many publishers, but all of them rejected it because it was original. Some publishers said that this book should be published in a Journal. These circumstances made me decide to give publicity to the important results obtained in this book piece by piece at Meetings of the American Mathematical Society.

Only the genius, like Nakano, has such a great courage to dare challenge such a theory. He made such a challenge to the famous Set Theory, and wrote a manuscript with title "Set Theory" in English. But when he presented it to the Society for publication, it was rejected by saying that as it was not a paper but a monograph. He was advised to find a publishing company for its publication. When he brought it, however, to a publishing company, it was rejected again by saying that this was not a book but a paper to be published in a journal. Back and forth, such that, it took a long time for his creative work to be published. In 1974, he passed away in Detroit. In 1978, after 4-years later, this book was finally published under the efforts of his pupils and followers. In the last paragraph of preface, Nakano wrote "I had been wondering about the existence of spaces which are neither finite or infinite. During the Christmas season of 1965, I got an idea of mathematical set theory and I was able to give a solution not only to this problem but also to the general continuum problem. This was truly a gift from God."

The first thing I learned about Nakano was his work on what is called the multiplicity theory of normal operators; that was something that had a great deal of interest for me once, and in my study of the subject I followed in the footsteps of Nakano (among others). Toward the end of his life he became interested in the foundations of set theory and distributed many preprints on that subject, but the professionals seemed to regard his approach with impatient suspicion.