Sunwolves coach Jamie Joseph has said he is temporarily stepping down from the role to undergo back surgery, with his assistant Tony Brown is taking control of the Super Rugby team until the end of the season.
Joseph, who is also the Japanese national team coach, is to return to his native New Zealand for the operation before returning to Japan to begin preparing the team for their November Tests.
"Though it was a very tough decision for me not to accompany the Sunwolves for the last three matches of the season, I had to think of what was best for the greater goal of Japanese rugby," Joseph said in a statement on Tuesday.
"The team will be in the very capable hands of Tony Brown and our support staff and I will look forward to continue to monitor their progress till the end of the Super Rugby Season for 2018."
Brown is also on Joseph's staff with the Japan team and the pair worked together at the Otago Highlanders.
The former All Blacks flyhalf succeeded Joseph as head coach of the Highlanders last year before he joined him in Japan.
The Sunwolves are bottom of the Super Rugby standings but have demonstrated this season signs of improvement under Joseph, who assumed the dual role to help streamline player development as Japan prepares to host the Rugby World Cup next year.
The Sunwolves face South Africa's Bulls in Singapore on Saturday before ending their season against the NSW Waratahs in Sydney and Queensland Reds in Brisbane.