Machiko Tsuzuki appears as a female character within the Black Jack OVA series. She is identified specifically as the wife of Kouichirou Tsuzuki. Her sole confirmed appearance occurs in episode 9 of the OVA, released in the year 2000. Attributes beyond these confirmed details, including physical traits, personality, occupation, or a narrative role across other Black Jack franchise media such as manga, films, television series, or spin-offs, remain undocumented within the provided sources.