Koichi Sasada is a programmer, mainly developing Ruby interpreter (CRuby/MRI). He received Ph.D (Information Science and Technology) from the University of Tokyo, 2007. He became a faculty of University of Tokyo (Assistant associate 2006-2008, Assistant professor 2008-2012). After the 13 years life in university, now, he is a member of Matz's team in Heroku, Inc. He is also a director of Ruby Association.