When Youda was young, Mizumura was his mentor in cabaret club business, they both worked together.
Yakuza 0: 1988-1989
Youda invites Majima to go inside Club Sunshine, then Majima sees him being threatened by Hino, owner of Club Mars. After knowing that Majima is the manager of Cabaret Grand, he requests Majima to become a Club Sunshine manager to take down Five Stars.
Yakuza Kiwami 2: 2006
Youda and Yuki were driven out of the club by Kanzaki. When Koyuki is kidnapped by Kanzaki, he and Majima rescue her and reveal that the Grand Prix host, Buono Isozaki has been working with Kanzaki to cheat.
After Yuki joins hostess roster, Youda asks Kiryu to open the business instead of Yuki.