As mentioned in footnote 34 (recital 49), PIHBOs are required, under Article 26(1) of the APPI, to verify the identity of a third party providing personal data to them and the "circumstances" under which such data was acquired by the third party (in case of personal data covered by this Decision, according to the APPI and Supplementary Rule (3) those circumstances shall include the fact that the data originates from the European Union as well as the purpose of the original data transfer). Among others, that measure aims at ensuring the lawfulness of data processing throughout the chain of PIHBOs handling the personal data. Furthermore, under Article 26(3) of the APPI, PIHBOs are required to keep a record of the date of receipt and the (mandatory) information received from the third party pursuant to paragraph 1, as well as the name of the individual concerned (data subject), the categories of data processed and, to the extent relevant, the fact that the data subject has given consent for sharing his/her personal data. As specified in Article 18 of the PPC Rules, those records must be preserved for a period of at least one to three years, depending on the circumstances. In the exercise of its tasks, the PPC can require the submission of such records (39).

A first protection is enshrined in Article 24 of the APPI which generally prohibits the transfer of personal data to a third party outside the territory of Japan without the prior consent of the individual concerned. Supplementary Rule (4) ensures that in the case of data transfers from the European Union such consent will be particularly well informed as it requires that the individual concerned shall be "provided information on the circumstances surrounding the transfer necessary for the principal to make a decision on his/her consent". On that basis, the data subject shall be informed of the fact that the data will be transferred abroad (outside the scope of application of the APPI) and of the specific country of destination. This will allow him/her to assess the risk for privacy involved with the transfer. Also, as can be inferred from Article 23 of the APPI (see recital 47), the information provided to the principal should cover the compulsory items under its paragraph 2, namely the categories of personal data provided to a third party and the method of disclosure.

In Japan, the authority in charge of monitoring and enforcing the APPI is the PPC. It is composed of a Chairperson and eight Commissioners appointed by the Prime Minister with the consent of both Houses of the Diet. The term of office for the Chairperson and each of the Commissioners is five years, with the possibility for reappointment (Article 64 of the APPI). Commissioners may only be dismissed for good cause in a limited set of exceptional circumstances (57) and must not be actively engaged in political activities. Moreover, under the APPI, full-time Commissioners must abstain from any other remunerated activities, or business activities. All Commissioners are also subject to internal rules preventing them from participation in deliberations in case of a possible conflict of interests. The PPC is assisted by a Secretariat, led by a Secretary-General, that has been established for the purpose of carrying out the tasks assigned to the PPC (Article 70 of the APPI). Both the Commissioners and all officials in the Secretariat are bound by strict rules of secrecy (Articles 72, 82 of the APPI).

Moreover, in two judgments from 1969 and 2008 (95), the Supreme Court of Japan has stipulated limitations with respect to non-compulsory measures that interfere with the right to privacy (96). In particular, the court considered that such measures must be "reasonable" and stay within "generally allowable limits", that is to say they must be necessary for the investigation of a suspect (collection of evidence) and carried out "by appropriate methods for achieving the purpose of [the] investigation" (97). The judgments show that this entails a proportionality test, taking into account all the circumstances of the case (e.g. the level of interference with the right to privacy, including the expectation of privacy, the seriousness of the crime, the likelihood to obtain useful evidence, the importance of that evidence, possible alternative means of investigation, etc.) (98).

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).