When the laureates of the 2023 Kyoto Prize were awarded their medals last month, there was a striking absence. Just weeks before the awards ceremony in Kyoto, Japan, Dr. Ryuzo Yanagimachi, the world-renowned scientist from the University of Hawaii at Manoa, passed away at age 95. Still, his contribution to the world of science was celebrated by his colleagues and by the international gathering.

His contribution to scientific discovery is experienced by millions more every day.

He worked in his office, which for much of his career was a large warehouse converted into a lab, and later a 100-square foot space, 12 hours a day, every day of the year. Yana, as his friends and colleagues called him, made numerous breakthroughs in fertilization technology, primarily a sperm injection technique that is now used around the world in human infertility clinics. The technique is particularly useful in helping infertile men become fathers, and in countries with declining birthrates. The first human pregnancy from this technique occurred in 1994.

Yana’s energy was inexhaustible, his willingness to collaborate was inspiring, and his enthusiasm for science was contagious. His colleagues can attest that he never saw science as a job — it was a passion. Scientists are artisans, he said.

He was born in 1927 in Ebetsu, Japan, and received his undergraduate and doctoral degrees from the University of Hokkaido. Unable to find a teaching or research position in Japan, he took a postdoctoral position at the Worcester Foundation for Biomedical Research in Massachusetts in 1960, focusing on fish fertility, and eventually working with mammals, particularly hamsters and mice. He moved to the University of Hawaii in 1966, where, despite officially retiring in 2005, he worked until just weeks before his death.

He started as an assistant professor at the John A. Burns School of Medicine’s Department of Anatomy and Reproductive Biology. Yana worked at UH for 38 years, and continued for 18 more as professor emeritus. Those 56 combined years resulted in globally recognized breakthroughs.

In addition to his achievements in IVF technologies, in 1997, at the age of 69, Yana’s team cloned the world’s first mouse. The journal Nature published this research, describing how he removed the nucleus from a living cell and injected it into an egg that also had its nucleus removed. The egg developed into an embryo, which was then implanted and allowed to develop. It is now known as the “Honolulu Technique.” The first mouse born through the Honolulu Technique is in the Smithsonian in Washington, D.C. The technique has led to improvements in livestock farming and the conservation of rare animal species.

After he published news of his success in cloning in 1998, funding for further research increased and in 2000 he founded and directed the Institute for Biogenesis Research at the University of Hawaii’s medical school. The institute, devoted to studying the formation and development of embryos, pushed the boundaries of science, and in 2004 Yana was able to produce pups from an infertile male mouse. This was significant in advancing research in human infertility. His passion for reproductive biology and cloning never waned. He repeatedly said his subject was Mother Nature.

His wife, Hiroko, collaborated with him and worked as a technician in his lab. She died in 2020. They did not have children of their own.

A celebration of Yana and the other Kyoto Prize laureates will occur in March 2024 in San Diego, and May 2024 in Oxford.

Yana’s work was about life. Families around the world are grateful that he made theirs better.

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Dean Nelson is the founder/director of the journalism program at Point Loma Nazarene University in San Diego, and a Kyoto Journalism Fellow.