The legal system governing privacy and data protection in Japan has its roots in the Constitution promulgated in 1946.

Article 13 of the Constitution states:

"All of the people shall be respected as individuals. Their right to life, liberty, and the pursuit of happiness shall, to the extent that it does not interfere with the public welfare, be the supreme consideration in legislation and in other governmental affairs."

Based on that Article, the Japanese Supreme Court has clarified the rights of individuals as regards the protection of personal information. In a decision of 1969, it recognised the right to privacy and data protection as a constitutional right (8). Notably, the Court held that "every individual has the liberty of protecting his/her own personal information from being disclosed to a third party or made public without good reason." Moreover, in a decision of 6 March 2008 ("Juki-Net") (9), the Supreme Court held that "citizens’ liberty in private life shall be protected against the exercise of public authority, and it can be construed that, as one of an individual's liberties in private life, every individual has the liberty of protecting his/her own personal information from being disclosed to a third party or being made public without good reason" (10).

These rights are subject to three types of restrictions, relating to the individual's own or third parties’ rights and interests (51), serious interference with the PIHBO's business operations (52) as well as cases in which disclosure would violate other laws or regulations (53). The situations in which these restrictions would apply are similar to some of the exceptions applicable under Article 23(1) of Regulation (EU) 2016/679, which allows for restrictions of the rights of individuals for reasons related to the "protection of the data subject or the rights and freedoms of others" or "other important objectives of general public interest". Although the category of cases in which disclosure would violate "other laws or regulations" may appear broad, laws and regulations providing for limitations in this regard must respect the constitutional right to privacy and may impose restrictions only to the extent that the exercise of this right would "interfere with the public welfare" (54). This requires a balancing of the interests at stake.

As an exercise of public authority, government access in Japan must be carried out in full respect of the law (legality principle). In this regard, the Constitution of Japan contains provisions limiting and framing the collection of personal data by public authorities. As already mentioned with respect to processing by business operators, basing itself on Article 13 of the Constitution which among others protects the right to liberty, the Supreme Court of Japan has recognised the right to privacy and data protection (72). One important aspect of that right is the freedom not to have one's personal information disclosed to a third party without permission (73). This implies a right to the effective protection of personal data against abuse and (in particular) illegal access. Additional protection is ensured by Article 35 of the Constitution on the right of all persons to be secure in their homes, papers and effects, which requires from public authorities to obtain a court warrant issued for "adequate cause" (74) in all cases of "searches and seizures". In its judgment of 15 March 2017 (GPS case), the Supreme Court has clarified that this warrant requirement applies whenever the government invades ("enters into") the private sphere in a way that suppresses the individual's will and thus by means of a "compulsory investigation". A judge may only issue such warrant based on a concrete suspicion of crimes, i.e. when provided with documentary evidence based on which the person concerned by the investigation can be considered as having committed a criminal offence (75). Consequently, Japanese authorities have no legal authority to collect personal information by compulsory means in situations where no violation of the law has yet occurred (76), for example in order to prevent a crime or other security threat (as is the case for investigations on grounds of national security).

Importantly, Article 21(2) of the Constitution guarantees the secrecy of all means of communication, with limitations only allowed by legislation on public interest grounds. Article 4 of the Telecommunications Business Act, according to which the secrecy of communications handled by a telecommunications carrier shall not be violated, implements this confidentiality requirement at the level of statutory law. This has been interpreted as prohibiting the disclosure of communications information, except with the consent of users or if based on one of the explicit exemptions from criminal liability under the Penal Code (77).

The Constitution also guarantees the right of access to the courts (Article 32) and the right to sue the State for redress in the case where an individual has suffered damage through the illegal act of a public official (Article 17).

As indicated in recital 115, any data collection as part of a coercive investigation must be specifically authorised by law and may only be carried out based on a court warrant "issued for adequate cause" (Article 35 of the Constitution). As regards the investigation of criminal offences, this requirement is reflected in the provisions of the Code of Criminal Procedure ("CCP"). According to Article 197(1) of the CCP, compulsory measures "shall not be applied unless special provisions have been established in this Code". With respect to the collection of electronic information, the only relevant (82) legal bases in this regard are Article 218 of the CCP (search and seizure) and Article 222-2 of the CCP, according to which compulsory measures for the interception of electronic communications without the consent of either party shall be executed based upon other acts, namely the Act on Wiretapping for Criminal Investigation ("Wiretapping Act"). In both cases, the warrant requirement applies.

To the extent such a request is directed at a business operator and concerns personal information, the business operator has to comply with the requirements of the APPI. According to Article 23(1) of the APPI, business operators may disclose personal information to third parties without consent of the individual concerned only in certain cases, including where the disclosure is "based on laws and regulations" (89). In the area of criminal law enforcement, the legal basis for such requests is provided by Article 197(2) of the CCP according to which "private organisations may be asked to report on necessary matters relating to the investigation." Since such an "enquiry sheet" is permissible only as part of a criminal investigation, it always presupposes a concrete suspicion of an already committed crime (90). Moreover, since such investigations are generally carried out by the Prefectural Police, the limitations pursuant to Article 2(2) of the Police Law (91) apply. According to that provision, the activities of the police are "strictly limited" to the fulfilment of their responsibilities and duties (that is to say the prevention, suppression and investigation of crimes). Moreover, in performing its duties, the police shall act in an impartial, unprejudiced and fair manner and must never abuse its powers "in such a way as to interfere with the rights and liberties of an individual guaranteed in the Constitution of Japan" (which include, as indicated, the right to privacy and data protection) (92).

Second, according to Article 62 of the Constitution, each House of the Japanese parliament (the Diet) may conduct investigations in relation to the government, including with respect to the lawfulness of information collection by the police. To that end, it may demand the presence and testimony of witnesses, and/or the production of records. Those powers of inquiry are further specified in the Diet Law, in particular Chapter XII. In particular, Article 104 of the Diet Law provides that the Cabinet, public agencies and other parts of the government "must comply with the requests of a House or any of its Committees for the production of reports and records necessary for consideration of investigation." Refusal to comply is allowed only if the government provides a plausible reason found acceptable by the Diet, or upon issuance of a formal declaration that the production of the reports or records would be "gravely detrimental to the national interest" (106). In addition, Diet members may ask written questions to the Cabinet (Articles 74, 75 of the Diet Law), and in the past such "written inquiries" have also addressed the handling of personal information by the administration (107). The Diet's role in supervising the executive is supported by reporting obligations, for instance pursuant to Article 29 of the Wiretapping Act.

In addition to monetary compensation, individuals may under certain conditions also obtain injunctive relief (e.g. the deletion of personal data collected by public authorities) based on their privacy rights under Article 13 of the Constitution (122).

As for the Prefectural Police, its responsibilities and duties include the "maintenance of public safety and order" (Article 35(2) in conjunction with Article 2(1) of the Police Law). Within this scope of jurisdiction, the police may collect information, but only on a voluntary basis without legal force. Moreover, the activities of the police shall be "strictly limited" to what is necessary to perform its duties. Moreover, it shall act in an "impartial, nonpartisan, unprejudiced and fair" manner and never abuse its powers "in any way such as to interfere with the rights and liberties of an individual guaranteed in the Constitution of Japan" (Article 2 of the Police Law).

Finally, the PSIA may carry out investigations under the Subversive Activities Prevention Act ("SAPA") and the Act on the Control of Organisations Which Have Committed Acts of Indiscriminate Mass Murder ("ACO") where such investigations are necessary to prepare the adoption of control measures against certain organisations (126). Under both Acts, upon request by the Director-General of the PSIA the Public Security Examination Commission may issue certain "dispositions" (surveillance/prohibitions in the case of the ACO (127), dissolution/prohibitions in the case of the SAPA (128) and in this context the PSIA may carry out investigations (129). According to the information received, these investigations are always conducted on a voluntary basis, meaning that the PSIA may not force an owner of personal information to provide such information (130). Each time, controls and investigations shall be conducted only to the minimum extent necessary to achieve the control purpose and shall not under any circumstances be carried out to "unreasonably" restrict the rights and freedoms guaranteed under the Constitution of Japan (Article 3(1) of SAPA/ACO). Moreover, according to Article 3(2) of the SAPA/ACO, the PSIA must under no circumstances abuse such controls, or the investigations carried out to prepare such controls. If a Public Security Intelligence Officer has abused his/her authority under the respective Act by forcing a person to do anything which the person is not required to, or by interfering with the exercise of a person's rights, (s)he may be subject to criminal sanctions pursuant to Article 45 SAPA or Article 42 ACO. Finally, both Acts explicitly prescribe that their provisions, including the powers granted therein, shall "not under any circumstances be subject to an expanded interpretation" (Article 2 of SAPA/ACO).

First, the Japanese Diet through its specialised committees may examine the lawfulness of investigations based on its powers of parliamentary scrutiny (Article 62 of the Constitution, Article 104 of the Diet Law; see recital 134). This oversight function is supported by specific reporting obligations on the activities carried out under some of the aforementioned legal bases (133).