A 57-year-old man on trial for stabbing a colleague to death at an Ikebukuro sushi restaurant showed no remorse in court, the victim's family told lay judges, describing a defendant who said his life in detention was "stress-free."
The lay-judge trial of Masato Ishioka opened at the Tokyo District Court, where a statement from the family of the victim, a 32-year-old coworker identified only as Mr. A, was read aloud at a hearing on November 4.
Ishioka went to the Ikebukuro Station west exit police box on July 25, 2025, and told officers he had stabbed someone. Officers who went to the sushi restaurant found Mr. A bleeding from the neck, chest and stomach. He was confirmed dead at the hospital he was taken to.
At the time of his arrest, Ishioka admitted the allegation, saying his relationship with Mr. A had not gone well and that his anger had exploded. He said he used a knife from the restaurant.
He pleaded guilty at the first hearing. He told the court he had been under stress because the staff ignored him. On the day of the killing he had greeted Mr. A, he said, and lashed out with a 29-centimeter beef knife because he was ignored and lost his temper.
A workplace isolation
Coworkers described a poor work attitude, saying Ishioka used his personal smartphone on the job, drank and was repeatedly late. He reacted with visible displeasure when reprimanded, and his relations with the staff worsened until he was isolated.
A doctor who conducted a psychiatric examination diagnosed him as having had an acute stress reaction. The attack appeared to be sudden, driven by a grudge that had built up.
Ishioka entered the courtroom in a black tracksuit, his head shaved and wearing silver-rimmed glasses. He bowed deeply when he caught his lawyer's eye. Once seated, he stared blankly and moved his lips silently, and appeared to be stifling a yawn.
A brother's statement
Mr. A's brother, four years his senior, attended as a bereaved family member and read the statement from behind a screen.
“I want to talk about what my younger brother was thinking as he lived his life.”Mr. A's brother, reading a statement at the Tokyo District Court
The three siblings, the brother, an elder sister and Mr. A, had practiced judo since childhood.