How Imminent Must a Threat Be to Justify Self-Defense Under Japanese Law?

The right to defend oneself or others from harm is a fundamental principle recognized in legal systems across the globe. In Japan, this right is enshrined in Article 36 of the Penal Code, which provides for the justification of "self-defense" (正当防衛 - seitō bōei). However, the availability of this defense is not unlimited; it is carefully circumscribed by several requirements designed to ensure that force is used only when genuinely necessary. One of the most critical of these conditions is that the defensive act must be against an "imminent and unjust infringement" (急迫不正の侵害 - kyūhaku fusei no shingai).

But what exactly does "imminent" mean in the context of Japanese criminal law? How close must the danger be? Can a threat of future harm suffice? This article explores the definition and judicial application of the imminence requirement, drawing insights from a key Supreme Court of Japan decision that navigated this complex issue in a heated confrontation.

The Core Concept of "Imminence" (急迫性 - Kyūhakusei) in Japanese Self-Defense

Article 36, paragraph 1 of the Japanese Penal Code states: "An act unavoidably performed to protect the rights of oneself or any other person against an imminent and unjust infringement is not punishable." The term "imminent and unjust infringement" forms the gateway to a valid self-defense claim. Let's break down its components:

1. Infringement (侵害 - shingai): There must be an actual or immediately threatened violation of a legally protected interest. This typically involves rights related to life, bodily integrity, or property, though other rights can also be subject to protection.
2. Unjust (不正 - fusei): The infringement must be unlawful or contrary to law. One cannot claim self-defense against a lawful act, such as a legal arrest carried out properly by a police officer, or against another person's act of justified self-defense.
3. Imminent (急迫 - kyūhaku): This is the temporal element and the primary focus here. The term "imminent" signifies that the unjust infringement is currently occurring or is so immediately impending that there is no time to seek protection from authorities (like the police) and defensive action is the only viable means to avert the harm. A mere fear of a possible future attack, or an attack that has already concluded, generally does not satisfy this requirement.

Purpose of the Imminence Requirement

The rationale behind the imminence requirement is to restrict the use of self-help force to situations of true emergency. It aims to prevent individuals from resorting to violence prematurely, based on speculation, or as a form of retaliation for past wrongs. Society entrusts the maintenance of order and the response to criminal acts primarily to state authorities. Self-defense is an exception, justified only when the state cannot realistically intervene in time to prevent immediate harm.

When Does an Attack Become "Imminent"?

Determining the precise moment an attack becomes "imminent" can be challenging. Japanese law and judicial practice generally do not require the defender to wait until the attacker has already struck the first blow or completed part of the harmful act. Imminence can be established when the attack is on the verge of happening—for example, when an assailant is clearly preparing to launch an assault, such as by drawing a weapon and advancing, or making overt physical movements indicative of an immediate strike. The danger must have progressed beyond mere preparation or threats of future action to a point where it poses a present and immediate peril.

When Does Imminence Cease?

Conversely, the right to use defensive force ceases once the imminent threat has passed. This can occur if the attacker:

• Clearly stops their attack and retreats.
• Is subdued or incapacitated.
• Otherwise indicates that they no longer pose an immediate danger.
  Any force used after the cessation of imminence is not considered self-defense and may constitute unlawful retaliation or a separate assault.

The Dormitory Altercation: Supreme Court Decision, January 30, 1984

A significant Supreme Court of Japan case that provides valuable insight into the application of the imminence requirement is the decision of January 30, 1984 (Saikō Saibansho Hanketsu, Shōwa 59-nen 1-gatsu 30-nichi, Keishū 38-kan 1-gō 185-ページ).

Factual Background

The defendant and the victim ("X") were co-workers residing in the same dormitory and had a history of mutual animosity that had been escalating. On the evening of the incident, the two had a verbal altercation at a nearby liquor store, during which X physically assaulted the defendant, punching him and breaking one of his teeth.

Angered by this, the defendant returned to the dormitory. Still fuming and intending to make X admit his fault, he armed himself with a wooden sword (bokutō) and also placed a pair of hairdresser's scissors in his back pocket. He then went to a second-floor hall in the dormitory to confront X. As the defendant admonished X, a colleague intervened and persuaded the defendant to put down the wooden sword and resolve the matter through discussion.

The defendant complied, throwing the wooden sword behind a shoe cabinet, and then turned and began to walk downstairs, verbally indicating his willingness to talk and, by his account, expecting X to follow suit for a discussion. However, X's reaction was entirely different. X suddenly retrieved the discarded wooden sword, rushed after the defendant, and began attacking him, striking him on the head and ankle.

Initially, the defendant attempted to evade X's attack. As the assault continued, the defendant took out the scissors he was carrying. After first brandishing them, ostensibly to ward off X, he ultimately stabbed X in the chest area. X died as a result of these stab wounds.

The legal question, particularly concerning imminence, was whether X’s attack with the wooden sword constituted an "imminent and unjust infringement" justifying self-defense, especially given the defendant's earlier aggressive actions (arming himself and initiating the confrontation in the hall). Lower courts had reached differing conclusions, with some potentially viewing the defendant as having provoked or willingly engaged in the fight, thereby negating his self-defense claim.

The Supreme Court's Reasoning on Imminence

The Supreme Court meticulously analyzed the sequence of events and the defendant's state of mind at the critical junctures. Its key findings regarding imminence were:

1. Shift in the Defendant's Intent: The Court placed significant weight on the defendant's actions after the colleague's intervention. When the defendant discarded the wooden sword and stated his intention to talk, the Court found it reasonable to believe that, at that specific moment, the defendant genuinely intended to de-escalate the situation and resolve it through dialogue. He expected X to reciprocate this shift.
2. Unforeseen Attack by X: From the defendant's perspective at the moment he turned to go downstairs unarmed, X's subsequent act of retrieving the wooden sword and launching a violent attack was unexpected. The Court acknowledged that the defendant’s behavior prior to discarding the sword (arming himself, confronting X) could suggest he anticipated further conflict. However, the act of disarming at the colleague's behest and verbally opting for discussion marked a potential turning point.
3. The Colleague's Intervention as a Break: The intervention by the colleague and the defendant's positive response to it (discarding the weapon) were viewed as crucial. The Court reasoned that if the defendant still anticipated a physical fight at that point, it would have been unnatural for him to discard his primary means of defense, especially knowing X's physical capabilities.
4. X's Attack as a New Infringement: Therefore, X's renewed and escalated assault with the wooden sword, after the defendant had disarmed and indicated a willingness to talk, was deemed to constitute an "imminent and unjust infringement." This assessment was made from the defendant's standpoint at that specific time, despite the preceding acrimony and his earlier confrontational posture.
5. Defendant's Initial Evasion: The Court also noted that upon being attacked by X with the wooden sword, the defendant did not immediately retaliate with the scissors. Instead, he first attempted to flee and evade the blows. This behavior was seen as consistent with someone reacting to an unexpected assault rather than someone eager to engage in combat.

Based on this analysis, the Supreme Court concluded that the imminence requirement for self-defense was satisfied with respect to X's attack with the wooden sword. (The Court ultimately found the defendant's use of scissors to be excessive self-defense (過剰防衛 - kajō bōei), leading to a conviction for a lesser offense, but the finding on imminence was crucial for allowing the self-defense framework to apply at all).

Significance of the Case

The 1984 Supreme Court decision is highly instructive on the application of the imminence standard:

• Dynamic Assessment: It highlights that imminence is not a static condition but must be assessed dynamically, based on the evolving circumstances of a confrontation. A situation that might not initially support self-defense can transform if one party makes a genuine effort to de-escalate or withdraw, and the other party then initiates or renews an attack.
• Defendant's Reasonable Perception: The defendant's subjective perception of the situation and their reasonable expectations at the critical moment are important factors, although these are always judged against the backdrop of objective facts.
• Impact of De-escalation: A clear act of de-escalation or disarmament by an individual, even one who may have previously been an aggressor or was prepared for conflict, can effectively "reset" the imminence analysis. If the other party then attacks, that attack can be considered a fresh, unjust, and imminent infringement.
• Distinction from General Foreseeability of Conflict: Even if a general atmosphere of conflict exists or a future confrontation is anticipated, the specific act that triggers the defensive response must itself meet the criteria of being an "imminent" attack.

Factors Influencing the Judicial Determination of Imminence

Japanese courts consider a range of factors when determining whether an "imminent and unjust infringement" existed:

1. Objective Circumstances of the Attack:
   • Attacker's Conduct: This includes any verbal threats, menacing gestures, physical movements towards the defender, and the possession or use of weapons by the attacker. The more concrete and immediate these indicators of attack, the more likely imminence will be found.
   • Proximity: The physical distance between the attacker and the defender is a key consideration.
   • Location and Environment: The nature of the location (e.g., confined space, availability of escape routes) can influence the perception of immediate danger.
2. Defendant's Subjective Belief and its Reasonableness:
   • The defendant must have actually believed that an attack was imminent.
   • This belief must also be objectively reasonable under the circumstances. A purely subjective, irrational fear will not suffice if a reasonable person in the same situation would not have perceived an immediate threat.
3. History and Relationship Between Parties:
   • A prior history of violence, threats, or serious conflict initiated by the attacker can make the defendant's perception of an imminent threat more reasonable. However, past grievances alone do not automatically justify the use of force in a current encounter; the present threat must still be imminent.
4. Provocation and Mutual Combat (喧嘩防衛 - Kenka Bōei):
   • If the defendant provoked the attack or willingly engaged in mutual combat (a "brawl defense" scenario), establishing that they were facing an "unjust" infringement that was "imminent" from their perspective becomes significantly more challenging. In such cases, the defendant may be seen as having contributed to or accepted the risk of combat.
   • However, as demonstrated by the 1984 Supreme Court case, even if there was initial fault or mutual escalation, a clear and genuine attempt by the defendant to withdraw or de-escalate, followed by a disproportionate or renewed attack by the other party, can revive the conditions for a legitimate self-defense claim, including the element of imminence from the other's renewed attack.
5. The Principle of "No Duty to Retreat":
   • Japanese law generally does not impose a strict legal duty to retreat before using defensive force, even if a safe avenue of escape is available. The primary focus is on the imminence and injustice of the attack and the necessity and proportionality of the defense.
   • However, the practical availability of a safe escape route might be considered by courts as one factor in the overall assessment of whether the defensive action was truly "unavoidable" (やむを得ずに - yamu o ezu ni), which is linked to the concept of necessity and, indirectly, to the gravity and immediacy of the threat. If a very minor threat could be easily avoided by simply stepping away, resorting to significant force might be deemed unnecessary or disproportionate, even if technically "imminent."

Comparing "Imminence" in Japan and the U.S.

While both Japanese and U.S. legal systems require an imminent threat for self-defense, the application and nuances can differ. U.S. law also speaks of "imminent danger," often meaning a threat that is immediate, pressing, and without reasonable opportunity for escape or recourse to law enforcement.

A notable difference lies in the "duty to retreat" doctrine. While Japan generally has no such formal duty, many U.S. jurisdictions historically imposed a duty to retreat before using deadly force if it could be done safely (except when in one's own home – the "castle doctrine"). However, a significant number of U.S. states have now adopted "Stand Your Ground" laws, which remove or reduce the duty to retreat in public places. This distinction can affect how the necessity of using force in the face of an imminent threat is perceived. In Japan, the absence of a retreat duty might place greater emphasis on the other elements like the injustice of the attack and the proportionality of the defense, once imminence is established.

Conclusion

The requirement of an "imminent and unjust infringement" is a critical safeguard in Japanese self-defense law, ensuring that the right to use force is reserved for situations of genuine and immediate necessity. "Imminence" is not a rigid, abstract concept but is determined through a highly fact-sensitive inquiry that considers the totality of the circumstances, including the objective nature of the threat and the defendant's reasonable perception of that threat.

The Supreme Court of Japan's 1984 decision in the dormitory altercation case provides a vital precedent, demonstrating that even within an ongoing and hostile confrontation, the dynamics can shift. A genuine attempt by one party to disengage or de-escalate can render a subsequent attack by the other party a new, imminent, and unjust infringement, thereby creating the conditions for a legitimate self-defense response. Ultimately, the Japanese legal system seeks to balance the individual's right to protect themselves from immediate harm against the broader societal interest in preventing unnecessary violence, and the imminence doctrine is a key tool in striking that balance.