The 22-year-old, capped 11 times, has scored three times in four games at the start of the new J-League season.
Muto, who scored 13 times last season and was named in the league's select XI, played for Japan during their run to the quarter-finals of the Asian Cup.
He retained his place in the squad selected by new coach Vahid Halilhodzic for his first matches in charge last month.
Muto graduated in economics from Keio University two weeks ago.
In February, Premier League leaders Chelsea announced a new shirt sponsorship deal with a Japanese tyre manufacturer worth a reported £40m a year.
Hakuna maoni:
Chapisha Maoni