When Ruriko Take’s husband succumbed to cancer two years ago, she was pained to see how he — even on his deathbed — continued to blame himself for the death of his teenage son more than two decades on.

In November 1996, the Takes lost their 16-year-old son Takakazu to a vicious murder by a gang of teenage thugs who repeatedly hit and kicked him, unprovoked, on an Osaka street. After beating him up, the ringleader of the group, a 16-year-old karate practitioner, tossed a cigarette butt at a helpless Takakazu and bragged about his martial arts skills, joking to the rest of the gang that he may even make it to a K-1 match.

Takakazu’s friends, who had all been petrified as the scene unfolded, immediately called Take for help once the ordeal was over. When Take arrived at the scene, she rushed him to a hospital, where her barely conscious son mumbled to her that he needed to “go” because he had a “promise to keep” — she would later learn he was talking about a plan to go on a date with his first girlfriend.