Kawakami Gensai, based on a photo. Gensai was one of the four Hitokiri (manslayers) of the Bakumatsu era, who committed political murders in the name of Sonno Joi (Revere the Emperor and Expel the Barbarians). Random fact: Gensai was used as one of the models for the fictional Himura Kenshin in "Ruruoni Kenshin".