A 45-year-old man has been arrested in Japan for allegedly killing his boss in Ota District over dissatisfaction with his bonus.
The victim, 44-year-old Akihiro Kawashima, director of an audio equipment company, was attacked in his apartment in Omorikita on January 7 and was confirmed dead the following day.
According to Tokyo Reporter, citing Japanese news agency Jiji Press on January 12, 2026, the suspect, Masahiro Yamanaka, the company’s sales manager, told police that “my bonus was reduced without any explanation.”
Yamanaka’s bonus, previously equivalent to 1.5 months’ salary, had been cut to one month’s salary. A December bonus statement was also found at the suspect’s residence.
Police allege that Yamanaka stabbed Kawashima more than 10 times in the neck, stomach, and other parts of his body. During questioning, Yamanaka admitted to stabbing the victim but claimed he had no intent to kill.
Authorities said the suspect and victim had been high school classmates, and Yamanaka joined the company around four years ago at Kawashima’s invitation to help improve company performance.
Yamanaka reportedly said, “If they don’t understand what I mean, I feel I need to change their mindset, even if it means hurting them.” Police believe Yamanaka waited for Kawashima near his apartment before carrying out the attack.
After the incident, the suspect was reportedly seen visiting several bars with a friend until the early hours of the next morning.
Kawashima sustained stab wounds to more than 10 areas of his body, including the neck and stomach, and police believe the nature of the injuries indicates a clear intent to kill. All evidence, including the knife used and blood-stained clothing, is being examined forensically.
The case has raised concerns about workplace stress and conflicts in Japan, highlighting how professional disputes can sometimes escalate into tragic outcomes.
