Career
He has played for Yanmar Diesel. Mizuguchi played for Yanmar Diesel from 1967 to 1971 and remained with the club, managing the reserve squad, Yanmar Club. When Yanmar decided to dissolve the reserve squad, he led some players into a new team under the auspices of Matsushita which would be the roots for the team that would become Matsushita Soccer Club/Gamba Osaka.
Mizuguchi managed Matsushita for most of the 1980s and engineered their rise through the divisions, winning the Emperor"s Cup in 1990.
In 1991 he turned over the reins to Kunishige Kamamoto, another Yanmar/Cerezo legend who now wanted to help the new Osaka power.