On February 22, 2015, Yasukawa was scheduled to challenge Yoshiko for the World of Stardom Championship in the main event of a Korakuen Hall show. However, the match resulted in a no contest when Yoshiko began to shoot on Yasukawa, legitimately assaulting her to the point that the match had to be stopped. Following the match, Yasukawa, with a bloody and badly swollen face, was rushed to a Tokyo hospital, where she was diagnosed with fractured cheek, nasal and orbital bones, which would require surgery. The incident received mainstream attention in Japan and became known as Seisan Matchi (凄惨マッチ, "Ghastly Match").
On May 1, Yasukawa was forced to vacate the Wonder of Stardom Championship due to the facial fractures inflicted on her earlier in the year. Yasukawa eventually returned to the ring on September 23, 2015. On December 1, Yasukawa announced she would retire from professional wrestling on December 23. In her retirement match, Yasukawa and Kyoko Kimura defeated Haruka Kato and Kairi Hojo. Afterwards, Yasukawa continued working for Stardom as the manager of the Oedo Tai stable.