National position of Japan (2021)

Introduction
This is the position of Japan on international law applicable to cyber operations. The position has been submitted in the context of the UN Governmental Group of Experts (GGE) on Cybersecurity and published on the Japanese MFA's website on 16 June 2021.

Applicability of international law
 "Existing international law, including the UN Charter in its entirety, is applicable to cyber operations. The 2015 GGE report mentions 11 voluntary, non-binding norms of responsible State behaviour. These items were agreed by Governmental experts as requiring implementation at least as norms, but they include items which affirm or relate to rights and obligations under international law. The inclusion of such norms among the 11 items does not mean that the rights and obligations under existing international law are extinguished or altered." 

Peaceful settlement of disputes
 "Any international disputes involving cyber operations must be settled through peaceful means pursuant to Article 2(3) of the UN Charter. In addition, pursuant to Article 33 of the UN Charter, the parties to any dispute involving cyber operations, the continuance of which is likely to endanger the maintenance of international peace and security, must first of allseek a solution by negotiation, enquiry, mediation, conciliation, arbitration, judicial settlement, resort to regional agencies or arrangements, or other peaceful means of their own choice. In order to ensure the peaceful settlement of disputes, the powers of the Security Council based on Chapters VI and VII of the UN Charter and the functions of the other UN organs, including ICJ based on Chapter XIV of the UN Charter and the Statute of the International Court of Justice should be used in disputes stemming from cyber operations." 

Sovereignty
 "A State must not violate the sovereignty of another State by cyber operations. Moreover, a State must not intervene in matters within domestic jurisdiction of another State by cyber operations."

"On the other hand, regarding a violation of sovereignty that does not necessarily constitute an intervention, in the Lotus case, the Permanent Court of International Justice held that a State may not exercise its power in the territory of another State, while, in the Island of Palmas case, the Arbitral Tribunal stated as follows: "Sovereignty in the relations between States signifies independence. Independence in regard to a portion of the globe is the right to exercise therein, to the exclusion of any other State, the functions of a State." Taking these and other judgments into account, the Government of Japan considers that there exist certain forms of violation of sovereignty which may not necessarily constitute unlawful intervention prohibited under the principle of non-intervention.

With respect to violation of sovereignty, the International Court of Justice (ICJ), in the Nicaragua case (1986), held that the United States had acted in breach of its obligation under customary international law not to intervene in the affairs of another State, and, in addition, that the United States, by directing or authorizing overflights of Nicaraguan territory, had acted in breach of its obligation under customary international law not to violate the sovereignty of another State. In addition, in the Costa Rica v. Nicaragua case (2015), the ICJ cited the absence of evidence that Costa Rica exercised authority on Nicaragua ’s territory as the reason for dismissing Nicaragua's claim concerning the violation of its territorial integrity and sovereignty. Considering these cases, it can be presumed that, in some cases, a violation of sovereignty constitutes a violation of international law even when it does not fall within the scope of unlawful intervention."

"An act of causing physical damage or loss of functionality by means of cyber operations against critical infrastructure, including medical institutions, may constitute an unlawful intervention, depending on the circumstances, and at any rate, it may constitute a violation of sovereignty. As various opinions were expressed on the relationship between violation of sovereignty and unlawful intervention at the sixth GGE and the OEWG, it is desirable that a common understanding be forged through State practices and future discussions." 

Prohibition of intervention
 "With respect to the principle of non-intervention, cyber operations may constitute unlawful intervention when requirements including the element of coercion, which are clarified in the Nicaragua judgement (1986), are met."

"An act of causing physical damage or loss of functionality by means of cyber operations against critical infrastructure, including medical institutions, may constitute an unlawful intervention, depending on the circumstances, and at any rate, it may constitute a violation of sovereignty. As various opinions were expressed on the relationship between violation of sovereignty and unlawful intervention at the sixth GGE and the OEWG, it is desirable that a common understanding be forged through State practices and future discussions." 

State responsibility
 "Internationally wrongful acts committed by a State in cyberspace entail State responsibility. An internationally wrongful act occurs when the conduct of a State consisting of an action or omission violates an obligation prescribed by primary rules of international law. In the case of cyber operations as well, there is an internationally wrongful act when a State violates primary rules, including the principles of sovereignty, non-intervention, prohibition of the use of force, as well as various principles of international humanitarian law such as the principle of prohibition of attacks on civilian objects, and respect for basic human rights."

"Regarding cyber operations as well, a State responsible for an internationally wrongful act is under the following obligations. First, the State shall cease the act if it is continuing. In addition, the State shall offer appropriate assurances and guarantees of non-repetition, if circumstances so require. Besides, the responsible State is under an obligation to make full reparation for the injury caused by the internationally wrongful act."

[...]

"There is an internationally wrongful act of a State when the act is attributable to the State under international law and when the act constitutes a breach of an obligation of the State under international law." 

Attribution
 "There is an internationally wrongful act of a State when the act is attributable to the State under international law and when the act constitutes a breach of an obligation of the State under international law. There are legal, political and technical aspects in discussing the attribution of conduct to a State with respect to cyber operations.

To invoke State responsibility under international law with respect to any act in cyberspace, it is necessary to consider whether the act is attributable to a specific State. On this topic, Articles 4 to 11 of the ILC’s Articles on State Responsibility provide useful reference. As a general rule, in such cases as a cyber operation conducted by a State organ, the act is considered to be attributable to the State. A cyber operation conducted by a non-State actor is, in principle, not attributable to a State. However, according to Article 8 of the ILC’s Articles on State Responsibility, the conduct of a person or group of persons shall be considered an act of a State if the person or group of persons is in fact acting on the instructions of, or under the direction or control of that State in carrying out the conduct." 

Countermeasures
 "Under international law, it is permitted, under certain conditions, to take countermeasures against internationally wrongful acts.

In general terms, under international law, a State which has been injured by an internationally wrongful act of another State may take, under certain conditions, countermeasures in order to induce the responsible State to comply with (i) the obligation to cease the international wrongful act and (ii) the obligation to make reparation.

General international law does not confine countermeasures to those with the same means as the preceding internationally wrongful act in response to which they are taken. Japan considers that this is the same for the countermeasures against internationally wrongful acts in cyberspace." 

Plea of necessity
 "The Government of Japan is of the view that a State may invoke necessity under international law when the requirements shown in Article 25 of the ILC’s Articles on State Responsibility are satisfied." 

Due diligence
<section begin=JP_2021 due diligence /> "States have a due diligence obligation regarding cyber operations under international law. Norm 13(c) and (f) and the second half of paragraph 28(e) of the 2015 GGE report are related to this obligation.

In the Corfu Channel case (1949), the ICJ referred to the existence of "every State’s obligation not to allow knowingly its territory to be used for acts contrary to the rights of other States". In relation to cyber operations, the due diligence obligation in this sense has significance."

"The outer limit of the due diligence obligation of territorial States with respect to cyber operations is not necessarily clear. By reference to these judgements related to the concept of the due diligence obligation, it seems necessary to consider on a case-by-case-basis the scope of the obligation taking into account such factors as the seriousness of the cyber operations in question and the capacity of the territorial States to influence a person or group of persons conducting the attacks.

In light of the above, at the least, for example, when a State has received a credible notification from another State of the possibility that a person or group of persons located in its territory and receiving from it financial and other forms of support may be involved in a cyber operation that may cause serious adverse consequences, such as damage to a target State's critical infrastructure, the due diligence obligation owed by the informed State is presumed to include the obligation to exercise its capacity to influence the state-supported person or group of personsso as to prevent them from implementing such cyber operations.

One characteristic of cyber operations is the difficulty of making judgment as to attribution to a State. In this respect, the due diligence obligation may provide grounds for invoking the responsibility of the State from the territory of which a cyber operation not attributable to any State originated. It is possible at least to invoke the responsibility of such a State for a breach of its due diligence obligation, even if it is difficult to prove the attribution of a cyber operation to any State." <section end=JP_2021 due diligence />

Use of force
<section begin=JP_2021 use of force /> "Under certain circumstances, a cyber operation may constitute the threat or use of force prohibited by Article 2(4) of the UN Charter. Pursuant to this article, all States shall refrain in their international relations from the threat or use of force. The Government of Japan presumes that as a general rule the threat of force refers to a State's act of threatening another State by indicating its intention or attitude of using force, without actually using force, unless its arguments or demands are accepted. The obligation to refrain from the threat or use of force in international relations is an important obligation relating to cyber operations." <section end=JP_2021 use of force />

Self-defence and armed attack
<section begin=JP_2021 self-defence, armed attack and use of force /> "When a cyber operation constitutes an armed attack under Article 51 of the UN Charter, States may exercise the inherent right of individual or collective self-defence recognized under Article 51 of the UN Charter." <section end=JP_2021 self-defence, armed attack and use of force />

International humanitarian law (jus in bello)
<section begin=JP_2021 IHL /> "International humanitarian law is also applicable to cyber operations.

In situations of armed conflict, the methods and means of warfare used by the parties to the conflict are subject to regulations under international humanitarian law. This extends to cyber operations implemented by the parties to the conflict. Several principles under international humanitarian law, including the principle of humanity, necessity, proportionality and distinction, are also applicable to acts in cyberspace. In paragraph 28(d) of the 2015 GGE report, those principles are referred to as "established international legal principles." This reference, considered together with the fact that this report affirms the applicability of existing international law, can be interpreted to affirm the applicability of those principles.

[..] In principle, the existence of an "armed conflict" is a prerequisite for the application of international humanitarian law. Under the Geneva Conventions, there is no particular definition of an "armed conflict," and therefore, whether or not a certain incident constitutes an "armed conflict" needs to be decided on a case-by-case basis, taking into account a number of elements, such as the manner of the actual attack and the intent of each party to the incident, in a comprehensive manner. If the effects of cyber operations are taken into consideration, the conduct of cyber operations alone may reach the threshold of an "armed conflict."

As affirming the applicability of international humanitarian law to cyber operations contributes to the regulation of methods and means of warfare, the argument that doing so will lead to the militarization of cyberspace is groundless.[...] On the other hand, modes of combat in cyberspace are different from those in traditional domains. Therefore, how international humanitarian law regarding, for example, the scope of combatants applies to cyberspace should be further discussed." <section end=JP_2021 IHL />

Attack (international humanitarian law)
<section begin=JP_2021 Attack (international humanitarian law) /> "[..] Meanwhile, Article 49 of the Additional Protocol I to the Geneva Conventions stipulates: "'Attacks' means acts of violence against the adversary, whether in offence or in defence." The Government of Japan understands that cyber operations that may cause the destruction or neutralization of military targets, for example, may also constitute "attacks" under international humanitarian law, depending on the circumstances […] For example, cyber operations during armed conflict that cause physical damage or loss of functionality to medical institutions may constitute a violation of international humanitarian law and therefore should be appropriately regulated.”

International human rights law
<section begin=JP_2021 international human rights law /> "International human rights law is also applicable to cyber operations. Individuals enjoy the same human rights with respect to cyber operations that they otherwise enjoy. Pursuant to international human rights law, States are under the obligation to respect human rights. The human rights that must be respected in cyberspace include all human rights that are recognized under international human rights law, such as civil, political, economic, social and cultural rights. The human rights that are particularly relevant in the context of cyberspace include the right to privacy, freedom of thought and conscience, freedom of expression, and guarantee of due process. The final sentence of paragraph 28(b) of the 2015 GGE report affirms the above. While Norm 13(e) of the report affirms some of the obligations under international human rights law, it does not change the obligations that are not mentioned therein." <section end=JP_2021 international human rights law />