Obituary: Dr Yukio Ôhashi (1955-2019)

It is with great sadness that we report the unexpected death of the distinguished Japanese historian of astronomy Dr Yukio Ôhashi on 31 October 2019, at the age of 64. In this obituary we provide information about Yukio's academic studies, his research interests, his involvement with astronomical societies, some of the conferences he attended, and his publications. We end with a listing of his English-language research papers.