One Act, Multiple Crimes? How Japanese Law Assesses the "Number of Offenses" (Sūsū no Hyōka)

When a person engages in a course of criminal conduct, their actions may simultaneously or sequentially violate multiple criminal statutes, or harm multiple victims or legal interests. A fundamental task for the Japanese criminal justice system in such situations is to determine the "number of offenses" (罪数 - sūsū, also sometimes referred to as zaishū; this assessment is often called sūsū no hyōka or zaishū no hyōka). This determination is not merely an academic exercise; it has profound practical implications for how crimes are charged by prosecutors, how trials are conducted, the application of principles like double jeopardy (一事不再理 - ichiji fusairi), and, most significantly, how sentences are imposed.

This article explores the core doctrines that Japanese law employs to classify the relationship between multiple potential offenses arising from a single act or a closely related series of acts. We will focus on key concepts such as conceptual concurrence (観念的競合 - kannenteki kyōgō), connected offenses (牽連犯 - kenrenhan), and cumulative offenses (併合罪 - heigōzai), illustrated by two guiding Supreme Court of Japan decisions involving child pornography and child sexual abuse.

Why Determining the "Number of Offenses" Matters

The accurate assessment of the number of crimes committed is crucial for several reasons:

1. Indictment and Prosecution: It dictates how prosecutors frame the charges against a defendant. Can they bring multiple counts for what appears to be a single course of conduct, or must the conduct be treated as a single offense with multiple facets?
2. Double Jeopardy (Ichiji Fusairi): The principle against double jeopardy, enshrined in Article 39 of the Constitution of Japan, prevents an individual from being tried or punished twice for the same offense. Correctly defining what constitutes a "single offense" versus multiple distinct offenses is therefore essential to upholding this fundamental right.
3. Sentencing: Japanese law has specific and distinct rules for how sentences are determined when multiple offenses are involved.
   • For conceptually concurrent crimes, the punishment is typically based on the most serious offense among those violated.
   • For cumulative crimes, the Penal Code allows for the aggregation of punishments, often up to a statutory maximum (e.g., 1.5 times the maximum for the most serious offense in the case of imprisonment, but not exceeding the sum of the maximums for all offenses).
   • The way offenses are counted directly impacts the potential severity of the overall sentence.
4. Application of Substantive and Procedural Rules: Various other legal rules, such as statutes of limitation, rules of evidence, or specific procedural requirements, may apply differently depending on how offenses are counted and classified.

Core Doctrines for Assessing the Number of Offenses

Japanese criminal law has developed several key doctrines to analyze and categorize situations where a defendant's conduct might give rise to multiple criminal violations:

A. Conceptual Concurrence (観念的競合 - Kannenteki Kyōgō)

This doctrine is defined in the first part of Article 54, paragraph 1 of the Penal Code: "When a single act constitutes two or more separate crimes..." It applies when one single, indivisible act by the defendant simultaneously violates multiple distinct penal provisions or results in multiple instances of the same crime against different legally protected interests of the same type (e.g., a single punch that injures two people simultaneously could be two counts of injury in conceptual concurrence).

• The "Single Act" Requirement: The cornerstone of conceptual concurrence is that the defendant's conduct must be naturally and legally regarded as a single, unitary action. Determining what constitutes a "single act" can sometimes be complex and involves both a naturalistic observation of the conduct and a normative legal evaluation.
• Legal Effect: Offenses in conceptual concurrence are treated as a single consolidated crime for sentencing purposes. The punishment imposed is that prescribed for the most serious (i.e., carrying the heaviest statutory penalty) of the violated provisions.

B. Connected Offenses (牽連犯 - Kenrenhan)

This doctrine, traditionally covered by the latter part of Article 54, paragraph 1 of the Penal Code (which refers to "a crime which is a means of another crime or a crime which is a result of another crime"), applied when multiple distinct criminal acts were committed in a close instrumental relationship, such as one act being a necessary means to commit another, or one act being a natural consequence of another, all typically in furtherance of a single primary criminal purpose. Classic examples included trespassing onto property (means) to commit theft therein (result), or committing arson (means) to fraudulently collect insurance money (result).

• Historical Legal Effect: Like conceptual concurrence, connected offenses were historically treated as a single consolidated crime for sentencing, with the punishment being that of the most serious offense among those connected.
• Narrowing of the Doctrine: It is crucial to understand that the scope of the kenrenhan doctrine has been significantly narrowed by judicial interpretation and legislative reforms, particularly following amendments to the Penal Code in 2003 (effective 2005). These changes aimed to restrict the application of kenrenhan, leading to more situations involving multiple related acts being treated as cumulative offenses (heigōzai), which allows for potentially more severe aggregate punishment. The modern application of kenrenhan is generally limited to situations where the connection between the acts is extremely close and inherently intertwined, such as the acts of forging a document and then immediately using that forged document to commit fraud.

C. Cumulative Offenses (併合罪 - Heigōzai)

This category, governed by Articles 45 through 51 of the Penal Code, applies when a person has committed two or more separate and distinct crimes for which final judgments have not yet been rendered, and which do not fall under the doctrines of conceptual concurrence or the (now narrowed) connected offenses. These are essentially multiple independent criminal acts committed by the same individual that are tried together.

• Legal Effect: The Penal Code provides specific rules for aggregating punishments for cumulative offenses. For crimes punishable by imprisonment with forced labor, for example, the maximum term for the cumulative offenses is generally determined by increasing the maximum statutory term for the most serious of the crimes by up to one-half, but with the caveat that this aggregated maximum cannot exceed the simple sum of the maximum terms for all the individual offenses. Similar rules apply for fines and other types of punishment. This system allows for an enhanced overall sentence that reflects the commission of multiple distinct criminal acts.

D. Comprehensive Single Crime (包括一罪 - Hōkatsu Ichizai)

For completeness, it's worth briefly mentioning "comprehensive single crime" (which was the subject of a previous article in this series). This doctrine is distinct from the above three. Hōkatsu ichizai applies when a series of similar criminal acts, often occurring over a period, are treated as constituting one single, continuous offense due to factors like a unity of criminal intent, a consistent modus operandi, and often, the practical indivisibility of the overall criminal enterprise (e.g., a continuous course of embezzlement from an employer, or a fraudulent fundraising scheme involving numerous small deceptions). This differs from conceptual concurrence (one act, multiple violations) or cumulative offenses (multiple distinct crimes).

Supreme Court Illustrations: Child Pornography and Sexual Abuse Cases

Two decisions from the Supreme Court of Japan in 2009 provide valuable illustrations of how these doctrines, particularly conceptual concurrence and cumulative offenses, are applied in practice.

Case 1: Distribution of Material Constituting Both Child Pornography and Obscenity

(Supreme Court Decision, July 7, 2009; Saikō Saibansho Kettei, Heisei 21-nen 7-gatsu 7-nichi, Keishū 63-kan 6-gō 507-ページ)

• Facts: The defendant in this case sold DVDs. The content of these DVDs had the dual characteristic of being child pornography (violating the Act on Punishment of Child Prostitution and Child Pornography, and Protection of Children - 児童買春、児童ポルノに係る行為等の処罰及び児童の保護等に関する法律, often called the 児童ポルノ禁止法, Jidō Poruno Kinshihō) and also qualifying as obscene material (violating Article 175 of the Penal Code, which prohibits the distribution of obscene materials - わいせつ物頒布罪, waisetsubutsu hanpuzai).
• The Legal Issue: If a single DVD embodies these two distinct criminal characteristics, and the defendant sells this one DVD, does this act of selling constitute two separate crimes (which would be treated as cumulative offenses), or is it a single act that simultaneously violates two different statutes (thus falling under conceptual concurrence)?
• The Supreme Court's Reasoning:
  • The Court held that the act of selling a single physical item (the DVD) that possesses these dual illicit characteristics constitutes one single, indivisible act of selling.
  • This single act of selling, however, simultaneously infringes upon two distinct legally protected interests: the interest protected by the Child Pornography Act (primarily the protection of children from sexual exploitation) and the interest protected by Article 175 of the Penal Code (related to public sexual morality).
  • Therefore, the Supreme Court concluded that the relationship between the charge of selling child pornography and the charge of distributing obscene material, when both arise from the sale of the same item in a single transaction, is one of conceptual concurrence (kannenteki kyōgō). The defendant would be punished based on the penalties for the more serious of the two offenses.
  • The Court also briefly touched upon a related issue: if a defendant possesses child pornography for the purpose of sale and then actually sells it, the acts of "possession for the purpose of sale" and the "actual sale" might, if committed as part of a single continuous intent and enterprise, be treated as a comprehensive single crime (hōkatsu ichizai) of violating the Child Pornography Act (which criminalizes both modes of conduct).
• Significance: This case clearly illustrates the application of conceptual concurrence when a single, indivisible act (selling one item) simultaneously satisfies the elements of two different criminal statutes because the object of that act has multiple illicit characteristics. It also hints at how different modes of conduct related to the same criminal subject matter (e.g., possession for sale and actual sale of the same illicit items) might be aggregated under the hōkatsu ichizai doctrine if part of a unified criminal plan.

Case 2: Child Sexual Abuse Coupled with Simultaneous Production of Child Pornography

(Supreme Court Decision, October 21, 2009; Saikō Saibansho Kettei, Heisei 21-nen 10-gatsu 21-nichi, Keishū 63-kan 8-gō 1070-ページ)

• Facts: In this case, the defendant committed acts of sexual abuse against a child (e.g., forcible indecent assault - 強制わいせつ, kyōsei waisetsu, under the Penal Code). Crucially, in the very course of committing this sexual assault, the defendant also filmed or photographed the abusive acts, thereby simultaneously producing child pornography (violating the Child Pornography Act).
• The Legal Issue: Is the act of committing forcible indecent assault and the contemporaneous act of producing child pornography (by recording the assault as it happens) considered a "single, indivisible act" subject to conceptual concurrence? Or are these two distinct criminal acts that should be treated as cumulative offenses, allowing for potentially greater punishment?
• The Supreme Court's Reasoning:
  • The Supreme Court determined that the act of forcible indecent assault and the act of producing child pornography by filming that assault, even if they occur simultaneously and are closely intertwined within the same criminal episode, are legally distinct criminal acts.
  • Different Protected Legal Interests: The Court emphasized that these two acts violate fundamentally different legally protected interests (保護法益 - hogo hōeki). Forcible indecent assault primarily harms the victim's sexual integrity and freedom. The production of child pornography, while also victimizing the child involved, additionally harms broader societal interests related to the protection of children from sexual exploitation and the prevention of the dissemination of such exploitative material.
  • Distinguishable Acts: The physical actions themselves, while contemporaneous, are distinguishable: the act of physical sexual assault versus the act of operating a recording device to capture those images.
  • Not Conceptual Concurrence or Connected Offenses: The Court concluded that this scenario does not meet the criteria for conceptual concurrence because the conduct cannot be fairly characterized as a "single, indivisible act" in the legal sense required. Furthermore, it found that the relationship between the assault and the filming did not fit the (now narrowed) definition of connected offenses (kenrenhan). One act (e.g., filming) was not merely an indispensable means to the other (assault), nor was one a direct and necessary consequence of the other in the strict sense required by the modern interpretation of kenrenhan. While the assault created the opportunity to film the illicit content, the act of filming was a separate volitional conduct with its own criminal character.
  • Therefore, the Supreme Court held that the forcible indecent assault and the contemporaneous production of child pornography in this context constitute two separate and distinct crimes. As such, they are properly treated as cumulative offenses (heigōzai), allowing for their punishments to be aggregated according to the rules for such offenses.
• Significance: This decision clearly illustrates the limits of the conceptual concurrence doctrine. Even when criminal acts are very closely related in time and occur within the same overall criminal episode, if they can be analytically distinguished as separate volitional conducts that violate distinct legally protected interests, they are likely to be treated as cumulative offenses. This outcome also reflects the judicial approach following the legislative narrowing of the kenrenhan doctrine, which has led to more situations involving multiple related wrongdoings being classified as heigōzai, thereby allowing for potentially more comprehensive punishment that reflects each distinct criminal violation.

Analyzing the "Single Act" for Conceptual Concurrence

The determination of what constitutes a "single, indivisible act" for the purpose of applying conceptual concurrence (kannenteki kyōgō) is a key analytical step and is not always straightforward. It involves both a naturalistic observation of the defendant's physical conduct and a normative legal evaluation. If the defendant's course of conduct, even if occurring over a very short period, can be naturally and legally divided into distinct phases, each involving a separate volitional impulse and targeting a distinct aspect of a criminal prohibition, courts may find multiple acts rather than a single one. The 2009 Supreme Court decision on child sexual abuse and simultaneous pornography production demonstrates that even if two types of criminal conduct occur at precisely the same time during one overall "episode," if they are analytically distinguishable as separate culpable acts violating separate legal interests, they will likely not be considered a "single act" for conceptual concurrence.

The Narrowed Scope of Connected Offenses (Kenrenhan)

It is also important to reiterate that the historical scope of the connected offenses (kenrenhan) doctrine has been significantly curtailed in Japanese criminal law. Many situations that might have previously been treated as kenrenhan (where, for example, one crime was merely a means to achieve another, such as trespassing to commit theft) are now more likely to be considered cumulative offenses (heigōzai). The modern application of kenrenhan is generally restricted to cases where the connection between the multiple criminal acts is extremely close, inherent, and almost inseparable, such as the acts of forging an official document (a means) and then immediately using that very forged document to defraud another party (the result). The Supreme Court in the 2009 child pornography production case clearly found that the sexual assault and the simultaneous filming, while closely related in opportunity, did not meet the stringent criteria for kenrenhan under its modern, narrowed interpretation.

Conclusion: A Framework for Assessing Multiple Violations

Determining the "number of offenses" (sūsū no hyōka) is a fundamental and often intricate task in the application of Japanese criminal law, with direct and significant consequences for how defendants are prosecuted and sentenced. The principal legal doctrines employed for this purpose include conceptual concurrence (kannenteki kyōgō), where a single, indivisible act by the defendant simultaneously breaches multiple criminal statutes; the now more narrowly applied doctrine of connected offenses (kenrenhan), for inherently intertwined acts in a means-result relationship; and the broad category of cumulative offenses (heigōzai), which applies to separate and distinct crimes committed by the same individual.

The Supreme Court of Japan's 2009 decisions provide crucial illustrations of these principles in action. The ruling on the distribution of a single DVD that constituted both child pornography and obscene material exemplifies conceptual concurrence: one act of selling, two statutory violations, but treated as a single offense for punishment based on the more serious crime. In stark contrast, the decision concerning the simultaneous commission of child sexual assault and the production of child pornography by filming that assault demonstrates the application of the cumulative offenses doctrine: despite their contemporaneous occurrence, these were deemed two distinct criminal acts violating separate legal interests, thus allowing for aggregated punishment.

This careful legal delineation reflects the Japanese criminal justice system's ongoing effort to accurately assess the true scope and nature of a defendant's criminality. By meticulously analyzing the relationship between various acts and the legal interests they infringe, courts aim to apply appropriate charging and sentencing principles that justly correspond to whether the conduct represents a single culpable impulse with multiple legal infractions or multiple distinct manifestations of criminal culpability.