This special session has been organized in honour of Atsuhiko Ochi, a colleague and longtime friend who passed away in April this year. During the session, we will go over his innovative scientific contributions, as well as his mentoring and guidance of students and the research team. We will also present his contributions to international R&D collaborations like RD51 and DRD1. In doing so, Atsuhiko always paid close attention to representing the Japanese community and its research activities. With this session, we would like to honor him together with all colleagues and friends present.