The research by Professor Ohtani started in 1981 when he was a Ph. D. student in Kyoto University. Since then he has been studying photocatalysis and related topics for more than 40 years and published more than 300 original papers (h-index: 70). After gaining his Ph. D. degree from Kyoto University in 1985, he became an assistant professor at the university. In 1996, he was promoted to an associate professor in the Graduate School of Science, Hokkaido University, and was then awarded a full professor position in Institute for Catalysis, Hokkaido University in 1998. He was awarded several awards from societies.