Abstract: On April 3, 2019, Dr. Goro Eguchi, a distinguished Japanese Developmental Biologist, passed away at the age of 85. Dr. Eguchi began his research at Nagoya University under the supervision of the famous Japanese embryologist, Professor Tadao Sato, who had once worked with the Nobel laureate, Professor Hans Spemann. Dr. Eguchi possessed creative talents and was excellent at sketching biological samples and constructing plastic-model ships. When he was a 3rd-year student in Nagoya, he was asked by his future mentor, Professor Sato, to draw an illustration of Spemann's house in Freiburg for the cover of Spemann's biography that was being translated into Japanese. Professor Sato was amazed by Dr. Eguchi's drawing and made him an offer to join his lab as a graduate student. Dr. Eguchi acknowledged that this event allowed him to learn more about Spemann's works on embryology and pushed him to become a developmental biologist. Since that time, Dr. Eguchi dedicated 50 years of research to studying lens regeneration in the newt. Dr. Eguchi was the first to discover that macrophages remove melanin from retinal pigmented epithelial (RPE) cells to make them transparent during lens regeneration (Eguchi, 1967). Dr. Eguchi's landmark work was the finding of trans-differentiation of a single isolated RPE cell into crystalline-producing lens cells in culture (Eguchi, Abe, & Watanabe, 1974). This was the first experimental demonstration in which fully differentiated mature cells in vertebrates changed their fate, i.e., de-differentiated and trans-differentiated into other cell types. Another surprising finding was that this re-programing always occurred from the RPE cells to lens cells and that the trans-differentiation program never changed even after the lens was removed more than 18 times across a 16-year lifespan of a single newt. This amazing observation was published with Dr. Tsonis, a former PhD student in Dr. Eguchi's lab at Nagoya University (Eguchi et al., 2011). Dr. Eguchi was also instrumental in educating and supporting many young researchers. When he moved to Kyoto University in 1968 as an Associate Professor to join Professor Tokindo S. Okada's lab, he took on a bright graduate student, Masatoshi Takeichi. Dr. Takeichi would go on to discover cell adhesion molecules, the Cadherin family proteins. Another student, Dr. Hajime Fujisawa, would initiate his pioneering work of axon guidance molecules, the Semaphorin/Plexin/Neuropirin family proteins. Among the young researchers, Dr. Eguchi supervised in Kyoto were Drs. Harukazu Nakamura, Kenji Watanabe, Shin-ichi Abe, and Masasuke Araki. Dr. Eguchi then returned to Nagoya University in 1976 as Professor in the Molecular Biology Institute and would later move to the National Institute of Basic Biology in 1983 to become Chairman of the Developmental Biology Division. In Nagoya, Drs. Kenji Watanabe, Ryuji Kodama, and Kiyokazu Agata supported Dr. Eguchi's research as staff members. During that time, Dr. Eguchi also served as President of the Japanese Society of Developmental Biologists. In 1996, Dr. Eguchi was invited to Kumamoto University as its President. He founded the Institute of Molecular Embryology and Genetics with Professors Shin-ichi Aizawa and Ken-ichi Yamamura in 2000. Although he no longer maintained his own lab in Kumamoto, he continued experiments at home with the help of his wife Yukiko, who assisted in removing newt lenses. She was co-authored in the Nature Communications paper mentioned above for her invaluable contribution to his regeneration experiments. In 2000, Dr. Eguchi was appointed to become Program Director of the JST grant for the “Recognition and Morphogenesis” research. This program was designed to support young scientists in the field of Developmental Biology and Neuroscience. In the first three fiscal years, he awarded nearly 40 individuals with this grant. Every year, Dr. Eguchi displayed his support of the young researchers by getting together with each of them so they could report their progress and discuss their results. Dr. Eguchi was a great mentor and always sat in the front row of the meeting room offering critical comments. Many of his former JST disciples have now become professors at major Universities and Research Institutes, training the next generation of young students of Eguchi School. Dr. Eguchi was awarded L'ordre des Palmes academiques in 1994 and the Emperor's Purple Medal in 1995 for his contribution to Developmental Biology. Dr. Eguchi was a warm-hearted mentor, and a serious scientist, indeed. Dr. Eguchi's sudden death is of course sad news to us, but his scientific spirit and personality will be remembered by all in the community of Developmental Biology.