Japan sevens coaches Tomohiro Segawa and Keiko Asami have both stood down from their roles, the Japan Rugby Football Union announced Thursday.
Segawa, who led the Japan men's team to a fourth-place finish at the Rio Olympics, will be replaced by New Zealander Damian Karauna.
"My next aim was to win a medal at the Tokyo Games, and to be told I'm leaving despite having such motivation was frankly disappointing," Segawa said in a news release.
"I believe the JRFU judged that a next step was needed in order to win a medal in 2020. Deep down I'm strongly fixated on continuing to work and my dream is a Japan sevens team winning a medal in the Olympics.
"I take pride in having this passion more than anyone. I'll keep studying hard and if I have a chance I'd like to come back to work in sevens."
Karauna, who as a player spent a couple of seasons with (Munakata) Sanix Blues, was an assistant coach to the New Zealand team beaten by Japan in Rio.
"I am very honored to be joining the Japan national sevens team," he said. "Japan is known for playing an exciting style of sevens and I look forward to assisting the team in building towards Tokyo 2020. After the success in Rio, our team will continue to grow by developing new players and achieving consistent results on the world sevens circuit."
Karauna's first tournament in charge of Japan, which is a core side on the 10-stop Sevens World Series, will be the Dubai Sevens from Dec. 2-3.
Asami led the Sakura Sevens to Rio, but the side somewhat underperformed and finished 10th, losing its core spot on the Women's Sevens Series.
"I assumed the huge role of head coach in 2012 and I kept on working to win a gold medal without looking back," she said. "The result at the Rio Games is solely down to my shortcomings.
"But with many female rugby players experiencing the Olympics for the first time, and developing into athletes, I believe the occasion provided a base to build on toward the 2020 Tokyo Games."
Asami will be replaced on a temporary basis by Hitoshi Inada.