Kashima Antlers said Monday manager Daiki Iwamasa is leaving the J. League first-division club upon the expiry of his contract at the end of the season.
The 41-year-old former Kashima and Japan defender returned to his old club as a coach last year and was promoted to manager midway through the campaign in August.
Kashima finished fifth in J1 this season while going out in the Emperor's Cup third round and the League Cup quarterfinals, missing out on a domestic title for the seventh straight year.
"I've spent every day thinking about Kashima and the players. I have no regrets," Iwamasa said in a club statement. "Thank you so much for the 12 years here, including my playing days."