The world of Human Genetics and Psychiatry lost an academic giant, Professor Eiji Inouye, on 17 October 2010, at the age of 90. He passed away from primary heart and secondary renal failure after a 3-week hospitalization at Tokyo University Hospital. The elder of his two daughters believes that her father consciously left this world on the 20th anniversary of her mother's—his beloved wife's—death. A miracle and a truly marvelous story, if so.

Professor Inouye was born in Tokyo in 1919. His family produced many distinguished ophthalmologists. He enrolled in the Tokyo Imperial University School of Medicine in 1939, yet his academic endeavors were cut short due to World War II (1941–1945).

Graduating early due to the war, he had little choice but to accept work as a navy surgeon. He was almost sent to Iwo Island (Iwojima), where Japanese military forces were almost entirely wiped out. His class was the hardest hit in the 150-year-long history of the School of Medicine—more than half of his classmates were lost to the war. Inouye witnessed refugees from Nagasaki shortly after the atomic bomb attack, recounting their ghostlike appearances, walking in single file with their faces devoid of expression—a sight that left him at a loss for words and acutely aware of the powerlessness of medicine in the face of such a tragedy.

After the end of the war in 1945, Inouye returned to the University of Tokyo and began work at the Department of Psychiatry. His main interests were in the fields of psychiatry and human genetics. He published his first paper entitled ‘A Study on Personality by the Twin Study Method’ in 1953, for which he received a Doctorate of Medicine from the University of Tokyo. In 1962, he became a professor of Brain Research at the University of Tokyo, and continued collaborating with his colleagues in the fields of psychiatry and human genetics. His main focus was to clarify the influence of hereditary and/or environmental factors not only on personality, intelligence and academic achievement, but also in the pathogenesis of mental disorders such as mental retardation, epilepsy, schizophrenia and neurosis, mainly by use of the twin method. Later, he expanded his research to the newly arising field of cytogenetics, and wrote many influential papers on the relationship between chromosome aberrations—especially sex chromosome anomalies—and mental disorders and/or criminal behavior. After retiring from the University of Tokyo in 1980, Inouye worked as Director of the Institute for Developmental Research in Aichi Prefecture from 1981 to 1984.

Among the contributions he made to the academic society, most noteworthy are the effort and time he spent in establishing the Japan Society of Human Genetics (JSHG). He was a founding member of JSHG, serving in various positions such as secretary, trustee, director and finally President of JSHG from 1977 to 1987. Inouye contributed greatly to the growth and innovation of JSHG. He became an honorable member of JSHG in 1989. In 1970, he received an award from JSHG titled, ‘Twin Studies and Human Behavioral Genetics’. Internationally, Inouye was a member of the Permanent Committee for International Congress of Human Genetics, and its Vice President from 1976 to 1981. He also served as a committee member at WHO.

He was acquainted with many researchers in psychiatric genetics as well as in human genetics, including Professor Erik Essen-Möller (1901–1992, honorable member of JSHG) from Sweden.

Inouye also established the Japan Society for Twin Studies (JSTS) in 1987, serving as its President from 1987 to 1992. In 1992, he organized the 7th International Congress of Twin Studies (ICTS) in Tokyo, Japan. He also played an important role in establishing the Japanese Society of Mental Deficiency and the Japanese Society for Congenital Anomalies.

In addition to being an accomplished researcher and making the aforementioned contributions to academic society, Inouye showed talent in education, inspiring many pupils with his knowledge and famously strict training methods. His stern and determined personality were said to be partly induced by his experiences of the war. Though he never was vocally anti-war, the loss of so many friends to the war seemed deeply rooted within his heart.

At home, Inouye showed deep affection for his two daughters, and they in turn respected their father very much. He was fond of gardening, playing golf, hiking, classical music and art appreciation. Inouye left a farewell poem (Japanese traditional Haiku) written in a memo handed over to his elder daughter 2 days before his passing:

October morning

Soul wavering to and fro

Touch of summerly heat

Professor Inouye's memory and legacy will remain forever etched in the minds of those who knew him. We would like to convey our warmest sympathy and heartfelt condolences to his two daughters and their family members.