Hwangbo Kwan has resigned as coach of South Korean champions FC Seoul after a run of poor results in this season's K-League.
Assistant coach Choi Yong-soo will take temporary charge of the club, with Seoul in 14th place after seven games, just two off the bottom with only one win.
Hwangbo arrived in January from Oita Trinita in Japan's second division. The departure of several key players and a failure of new signings to settle led to a 2-0 home defeat on the opening day of the season at the hands of bitter rivals Suwon Bluewings.
Results did not improve and last weekend's 1-0 loss at struggling Gwangju FC led Hwangbo to give the club his notice.
"It is the first time in our 28 years that we have lost a coach in the middle of the season,'' said Seoul chief executive Han Woon-soo. "Coach Hwangbo told us of his intention to resign and we accepted that. We all agree that there is a need for a change.''
Seoul host Jeju United on Saturday and then Al Ain on May 4 in the penultimate group match in the Asian Champions League. After four games, Seoul sit in second in their group with seven points.