ブラウブリッツ秋田
After being translator for Ivica Osim and his son Amar Osim during his spell as JEF United Chiba's coach until 2007, Mase became a coach at the club. Form 2010, he became a coach at Fagiano Okayama (2010-2012) and Tokyo Verdy (2013). In January 2015, he became the manager at Blaublitz Akita, as his mother is from Oga, Akita. In 2017, he moved to Ehime FC. However the club results were bad in 2018 season, he was sacked by Ehime FC on May when the club was at the 20th place of 22 clubs. In July 2018, he signed with former club Blaublitz Akita and became a manager for the first time in 2 years.