Answer
Yes, Takeshi Okada achieved domestic success as a coach. Notably, he guided Sanfrecce Hiroshima to the J1 League title in 2012, ending the club's 26-year wait for a top-flight championship. In addition, Okada led the team to three consecutive J.League Cup triumphs from 2010 to 2012, further solidifying his status as a successful domestic coach.