Case of Injury (Reiwa 6 (Wa) No. 280)

In early 2025, at a commercial establishment in Tokyo, a verbal altercation between two men over a trivial matter escalated into physical violence. The defendant, a male in his 30s, struck the victim, a male in his 40s, in the face with his fist. The assault resulted in a nasal bone fracture requiring approximately one month of medical treatment. The Tokyo District Public Prosecutors Office indicted the defendant for the crime of Injury under Article 204 of the Japanese Penal Code. During the trial at the Tokyo District Court, the defense argued that the defendant was acting in self-defense after being pushed first, while the prosecution maintained the retaliation was disproportionate. The court ultimately found the defendant guilty but accepted partial claims of provocation, ruling that the level of force used was excessive and constituted an illegal act of injury.

The Tokyo District Court found the defendant guilty of causing injury. The court ruled that while the victim initiated the physical contact, the defendant's violent retaliation was a disproportionate act of excessive self-defense. The defendant was sentenced to one year in prison, suspended for three years. The verdict was finalized without appeal from either party.

The primary legal dispute centered on whether the defendant's actions constituted legitimate self-defense (Seito Boei) or excessive self-defense (Kajo Boei) under Article 36 of the Penal Code. The defense argued the defendant instinctively reacted to an unprovoked push. The prosecution argued that punching a person's face with a closed fist far exceeded the necessary and reasonable force to defend against a push, moving from defense to a retaliatory attack. The court had to strictly assess the proportionality of the force used against the initial provocation.

The case sparked discussion among legal commentators regarding the strict boundaries of self-defense under Japanese law. It served as a precedent example highlighting how Japanese courts maintain a high threshold for accepting self-defense claims in public altercations. Legal experts noted that the ruling reinforced the principle that physical retaliation, particularly closed-fist strikes to the face during minor scuffles, is likely to be treated as a crime of injury rather than a protected act of self-defense, emphasizing the societal expectation to de-escalate or retreat from confrontations.