"Punishable Illegality" on Trial: A 10-Yen Crime and a Japanese Supreme Court Divided

Decision Date: June 24, 1986

Does every violation of the law, no matter how minor, warrant the full weight of a criminal conviction? This question probes the very spirit of justice, asking whether the law should operate as an inflexible machine or as a tool of reason, capable of distinguishing between genuinely harmful acts and technical infractions that are too trivial to prosecute. In Japan, this concept is known as kabatsuteki ihōsei, or "punishable illegality," a doctrine holding that some acts, despite formally meeting the definition of a crime, may lack the requisite social harm to justify criminal punishment.

On June 24, 1986, this doctrine was put to a severe test before the Supreme Court of Japan in the famous "Magic Phone" case. The case involved a device designed to defraud the public phone company, a single test call resulting in a loss of just 10 yen, and a defendant whose motives seemed more misguided than malicious. The resulting decision, complete with a powerful dissent, provides a masterclass in the tensions between formal legality and substantive justice, and reveals the profound philosophical divisions that can exist even at the highest levels of the judiciary.

The Factual Background: A Favor for a Friend and a Single Test Call

[cite_start]The defendant in the case was persuaded by an acquaintance he had once been indebted to, to purchase two units of an electronic device known as a "Magic Phone." [cite_start]This device, when attached to the receiving party's telephone, was designed to disable the billing meter for the calling party, allowing one to make phone calls without incurring charges.

[cite_start]The defendant purchased two devices. [cite_start]To test its function, he had an employee attach one unit to a telephone in his company office. [cite_start]He then instructed the employee to call that office phone from a public telephone. [cite_start]The employee reported that the 10-yen coin he inserted had been returned after the call, confirming the Magic Phone’s function.

[cite_start]Feeling uneasy about the device, the defendant consulted his company's retained lawyer the very next day. [cite_start]The lawyer told him the device was problematic and that he should not use it. [cite_start]Following this advice, the defendant immediately had the Magic Phone removed. [cite_start]The device had been installed for less than two days, and the court confirmed that no other calls had been made with it during that time.

[cite_start]Later, when police were investigating the seller of the devices, they learned of the defendant's purchase. [cite_start]The defendant was told that the police were primarily interested in pursuing the manufacturers and sellers and was asked to cooperate. [cite_start]He did so willingly. [cite_start]Despite this cooperation, the defendant was charged with two crimes: violation of the Wire Telecommunications Act and fraudulent obstruction of business.

A Judicial Tug-of-War: From Acquittal to Conviction

The defendant’s case took a winding path through the courts, with each level offering a starkly different interpretation of his actions.

• [cite_start]The Summary Court (First Instance): Acquittal based on Triviality. The trial court found the defendant not guilty, invoking the doctrine of punishable illegality. The judge cited a number of mitigating factors:
  • [cite_start]His motive for purchasing the device was primarily to help a friend in financial distress.
  • [cite_start]He attached it to a low-use private phone.
  • [cite_start]He conducted only a single test call.
  • [cite_start]The actual financial damage to the phone company (then Denden-kōsha, now NTT) was a mere 10 yen.
  • [cite_start]He immediately removed the device after consulting his lawyer.
  • [cite_start]He fully cooperated with the police investigation.
    [cite_start]Taking these factors together, the court concluded that the defendant’s act was a "trivial illegality" that did not warrant criminal sanction.
• [cite_start]The High Court: Reversal and Conviction. The prosecution appealed, and the High Court reversed the acquittal, finding the defendant guilty. [cite_start]The appellate court systematically dismantled the trial court’s reasoning, arguing that the defendant's good-faith motive was not proven, and that the minimal use, quick removal, and cooperation were all post-crime circumstances relevant only to sentencing, not to the fundamental question of illegality. [cite_start]The defendant then appealed to the Supreme Court.

The Supreme Court Weighs In: A Terse Ruling and a Deep Divide

The Supreme Court upheld the High Court's conviction, but its decision was far from unanimous and revealed a deep fissure in judicial philosophy.

The Majority Opinion:
The majority's decision was incredibly brief. [cite_start]It simply stated that, regarding the defendant's act of attaching the Magic Phone, "even if circumstances existed such as the defendant having only attempted a single call and then having removed the said device, the illegality of the act is not negated on that account." [cite_start]The High Court’s judgment, it concluded, was "appropriate."

The Concurring Opinion: The Logic of Systemic Harm.
[cite_start]To understand the majority's likely reasoning, one must turn to the supplementary opinion by Justice Ouchi. He argued that the concept of punishable illegality was entirely misplaced here. [cite_start]A "Magic Phone," he noted, is simply a "machine that makes phone calls free," and any ordinary person would recognize that installing such a device is illegal.

[cite_start]Crucially, he characterized the crimes in question (interference with telecommunications and business) as "danger offenses" (kiken-han). [cite_start]This means the crime is complete when an act creating a risk of harm is committed, regardless of the actual outcome. [cite_start]The installation of the device itself constituted the crime. [cite_start]The fact that the financial loss was only 10 yen was irrelevant. [cite_start]He distinguished this case from historical precedents on punishable illegality, such as the famous 1910 "one-rin tobacco case," which he argued dealt with "trivial infractions that an ordinary person might commit under the circumstances." [cite_start]Deliberately installing a sophisticated illegal device, he contended, is an act of a different character entirely.

The Dissenting Opinion: A Defense of Judicial Discretion.
[cite_start]In a powerful dissent, Justice Taniguchi articulated a robust defense of punishable illegality. [cite_start]He revisited all the mitigating facts from the trial court's decision, arguing that they painted a picture of a defendant who did not act with a determined "consciousness hostile to the law." [cite_start]He bought the device out of a sense of obligation to a friend, tested it once out of curiosity, and stopped immediately upon receiving legal advice.

[cite_start]Justice Taniguchi argued that courts possess a "law-and-policy-making function" that allows them—and indeed, obligates them—to find a defendant not guilty when their illegality and responsibility are "extremely low." [cite_start]He viewed the act through the lens of its actual result—a 10-yen harm—and concluded that the defendant's conduct fell far short of the threshold for criminal punishment.

The Deeper Debate: What Makes a Crime "Trivial"?

The split on the Supreme Court bench reflects a long-standing debate in Japanese criminal law theory: what is the true measure of a crime's seriousness?

• Result-Oriented vs. Act-Oriented Illegality: The dissent adopted a result-oriented view. The tangible harm was 10 yen, an amount so small as to be trivial. The concurrence, by contrast, took an act-oriented view. The act itself—installing a device designed to defeat a public utility's billing system—is an inherently anti-social act that attacks the integrity of the system.
• The Nature of the Harm: From the perspective of the telephone corporation, the harm is not the loss of 10 yen. The harm is the existence of a device that renders its automated billing system ineffective. If such devices were tolerated, the company could be forced into costly systemic upgrades to defend against them. [cite_start]From this viewpoint, the potential harm is immense, and the act of installing the device is a serious attack on the business.
• The Role of Post-Crime Behavior: The judges also disagreed on the significance of the defendant’s actions after the test call. The majority and concurring opinions saw his consultation with a lawyer and removal of the device as matters relevant only to sentencing. [cite_start]The dissent, however, viewed these actions as crucial evidence of his low culpability and lack of a firm criminal resolve, making them relevant to the fundamental question of whether he should be punished at all.

Conclusion: Drawing a Line Against Systemic Threats

The 1986 "Magic Phone" case serves as a crucial marker for the limits of the punishable illegality doctrine in Japan. The Supreme Court's majority decision signals a strong reluctance to apply the doctrine to crimes that, while producing minimal immediate harm, represent a deliberate attack on the integrity of a technical or commercial system. It prioritizes the inherent wrongfulness of the act and the potential for systemic risk over the triviality of the specific outcome.

However, the powerful and detailed dissenting opinion ensures that the debate remains vibrant. It champions a vision of the judiciary as a pragmatic and equitable institution, empowered with a policy-making function to prevent the law from becoming an instrument of disproportionate punishment. The "Magic Phone" case, therefore, endures not as a final resolution, but as a perfect illustration of the ongoing, essential dialogue within the law about where to draw the line between a crime and an infraction too minor to matter.