Kotari was hurt during his August 2 fight against Yamato Hata in Tokyo and was rushed to the hospital, where he underwent emergency brain surgery for a subdural hematoma bleeding between the skull and the brain.
His death was confirmed on Friday. Kotari is the second prominent boxer to die in 2025, following the passing of Ireland’s John Cooney in February after a bout in Belfast.
In response to the tragedy, the Japan Boxing Commission has announced that all Oriental and Pacific Boxing Federation title fights will be reduced from 12 rounds to 10.