The Obligation of Self-Restraint in Undelimited Maritime Areas

The Obligation of Self-Restraint
in Undelimited Maritime Areas*
Kentaro Nishimoto**
Abstract
As recent developments between Japan and China in the East China Sea show, unilateral
activities in undelimited maritime areas can give rise to tension. Articles 74(3) and 83(3)of the United Nations Convention on the Law of the Sea (UNCLOS) provide an obligation
for the States concerned not to jeopardize or hamper reaching of the final agreement(“the obligation of self-restraint”). However, the extent to which the obligation prohibits
unilateral activities has been a subject of discussion. This article addresses this issue by
mainly examining the relevant case law of international courts and tribunals. It finds thata consistent standard for distinguishing permissible and impermissible activities is yet
to be developed, but there is a noticeable trend where the obligation of self-restraint isincreasingly viewed as an obligation not limited to refraining from specific types of activities
that could be identified in general and in the abstract. The ar ticle fur ther addresses
questions concerning the appropriate responses to be taken by coastal States in the faceof a violation of the obligation of self-restraint by another State, including whether thecompulsory dispute settlement procedure of UNCLOS could be invoked against a State thathas made an optional exception declaration under Article 298(1)(a) of UNCLOS.

Introduction

China has been accelerating its resource development activities in the East China Sea.
To date, it has built 16 offshore structures near the geographic equidistance line
between Japan and China, on the Chinese side of the line.1 The government of Japan
has expressed regret over Chinaʼs unilateral pursuit of development and has requested
China to cease all unilateral development activities, as the exclusive economic zone (EEZ) andthe continental shelf is yet to be delimited between the two States.2 As this situation illustrates,
unilateral activities have frequently given rise to tension, in maritime areas subject to overlapping
claims to EEZs and continental shelves by more than two parties and where the maritime
boundary is yet to be agreed (hereinafter referred to as “undelimited maritime areas”).
The United Nations Convention on the Law of the Sea (UNCLOS) provides that, pending
agreement on the delimitation of the EEZ and continental shelf, “the States concerned, in a spiritof understanding and cooperation, shall make every effort to enter into provisional arrangementsof a practical nature and, during the transitional period, not to jeopardize or hamper the reaching*This essay was originally published on Kokusai Mondai [International Affairs], No. 674, Sep. 2018.

** Kentaro Nishimoto is a professor in the School of Law at Tohoku University.
1

Ministry of Foreign Affairs of Japan, Diplomatic Bluebook 2018 (Ministry of Foreign Affairs, 2018), p.
58.

2

Ministry of Foreign Affairs of Japan, The Current Status of China’s Unilateral Development of Natural
Resources in the East China Sea (https://www.mofa.go.jp/a_o/c_m1/page3e_000356.html).

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Kentaro Nishimotoof the final agreement” (Articles 74(3) and 83(3)). In other words, with respect to undelimited
maritime areas, the States concerned have an obligation to: 1) make ef for ts to enter into
provisional arrangements; and 2) not to jeopardize or hamper the reaching of a final agreement.
The second obligation is often referred to as the “obligation of self-restraint,” as it requires
the States concerned to practice a certain degree of self-restraint in their behavior.3 Unilateral
activities in undelimited maritime areas raise the question of whether they are in breach of theobligation of self-restraint.
It is not a simple matter to determine what kinds of activities constitute a violation of theobligation of self-restraint. For some time, the only precedent in which an international court
or tribunal directly addressed the obligation of self-restraint was the award rendered in 2007
by the Arbitral Tribunal constituted under Annex VII of UNCLOS, in the maritime delimitation
dispute between Guyana and Suriname. The subsequent discussion concerning the obligationof self-restraint has revolved around the criteria given in the arbitral award. More recently, theSpecial Chamber of the International Tribunal for the Law of the Sea (ITLOS) addressed theobligation of self-restraint in the case concerning the delimitation of the maritime boundar y
between Ghana and Côte dʼIvoire (Provisional Measures Order of 25 April 2015 and Judgmentof 23 September 2017). Focusing mainly on the two cases, this article will examine the issues
regarding the obligation of self-restraint and the measures that could be taken against a breachof the obligation. Because the two cases concerned the development of oil resources, which isalso at issue between Japan and China, this article will focus primarily on the obligation of selfrestraint as it relates to the development of oil and mineral resources.

1. The Obligation of Self-Restraint in International Case Law
There is general consensus that the intent of the obligation of self-restraint in undelimited
maritime areas is not to prohibit all unilateral activities pending delimitation.4 In the first place,the text of Articles 74(3) and 83(3) of UNCLOS envisages certain activities taking place. During
the drafting of the Convention, some States proposed that a moratorium be placed on resource
exploration and development in undelimited maritime areas. However, this proposal was not
accepted, and the present text was eventually adopted.5 The question, therefore, is as follows: ofthe unilateral activities not based on provisional arrangements that are undertaken in undelimited
maritime areas, how do we distinguish activities that constitute a violation of the obligation to
exercise self-restraint from those that do not?

3

It should be noted that the obligation as provided under the Convention is an obligation for Statesconcerned to “make every effort not to jeopardize or hamper the reaching of the final agreement.”
Caution is required not to draw any inferences from the term “obligation of self-restraint” itself, which isused in this article as a shorthand and is not a term actually used in the Convention.

4

Satya N. Nandan and Shabtai Rosenne (eds.), United Nations Convention on the Law of the Sea: A
Commentary (Martinus Nijhoff, 2002), Vol. II, p. 984; Alexander Proelss (ed.), United Nations Convention
on the Law of the Sea: A Commentary (Beck/Hart/Nomos, 2017), pp. 578–579, 663; Yumi Nishimura,“Nicchū tairikudana no kyōkai kakutei mondai to sono shori hōsaku” [The issue of delimitation of thecontinental shelf between Japan and China and the ways for its resolution], Jurist, No. 1321 (2006), p. 55.

5Youri van Logchem, “The Scope for Unilateralism in Disputed Maritime Areas,” in Clive H. Schofield
et al. (eds.), The Limits of Maritime Jurisdiction (Martinus Nijhoff, 2013), pp. 179–181; Akio Morita,“Keisō kaiiki ni okeru katsudō no kokusai hōjō no hyōka―nicchū nikkan kan no shomondai wo tegakari
toshite” [Assessing activities in disputed maritime areas under international law: various issues between
Japan and China, and Japan and South Korea], in Sōji Yamamoto et al. (eds.), Kaij hoan h sei―kaiy hto kokunaih no k saku [The Law and Institutions of Maritime Security: the interaction between the lawof the sea and domestic law] (Sanseidō, 2009), p. 392.

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The Obligation of Self-Restraint in Undelimited Maritime Areas(1) Guyana/Suriname Case
The dispute between Guyana and Suriname concerned the delimitation of their territorial seas,
EEZs and continental shelves, as well as the development of petroleum resources pending
delimitation. The dispute was referred to an Arbitral Tribunal constituted under Annex VII of
UNCLOS. In the maritime area disputed by the two States, Guyana had granted several privatecompanies permission to engage in oil exploration. One of the companies was CGX Resources
Inc. of Canada, whose oil rig encountered an incident in which it was ordered by the Surinameʼsnavy to leave the area (the “CGX Incident”). Suriname claimed that Guyana had violated theobligation of self-restraint by authorizing exploratory drilling to be undertaken in the disputedarea; Guyana claimed that the conduct of the Surinamese navy was in violation of the sameobligation, and also constituted a threat of force in breach of the Charter of the United Nations.
As a general matter, the Arbitral Tribunal stated that unilateral activities can be undertaken indisputed maritime areas without provisional arrangements, so long as the activities in question do
not have the effect of jeopardizing or hampering the reaching of a final agreement.6 Further, theTribunal adopted the view that activities that cause physical change to the marine environment
are not permitted unless undertaken pursuant to a provisional arrangement, because they would
cause permanent change and ultimately jeopardize or hamper the reaching of a final agreement.
Activities that did not result in physical change, on the other hand, were to be generally regarded
permissible.7 Based on this standard, the Arbitral Tribunal decided that Guyanaʼs grantingof explorator y drilling was a violation of the obligation of self-restraint. At the same time, it
concluded that allowing seismic testing did not constitute such a violation in the circumstances athand.8The Arbitral Tribunal stated that the distinction based on physical change to the marine
environment is consistent with the jurisprudence of international courts and tribunals on interim
measures.9 In particular, the Arbitral Tribunal cited the decision of the International Court ofJustice (ICJ) in the Aegean Sea Continental Shelf case. In that case, Greece requested interim
measures ordering Turkey to refrain from exploration activities in the disputed maritime
area.10 The ICJ ultimately declined to indicate interim measures, pointing out that Turkeyʼs
actions did not create a risk of irreparable prejudice to the rights claimed by Greeceʼs for thefollowing three reasons: 1) the seismic exploration did not involve any risk of physical damage
to the seabed; 2) the activity in question was of a transitory character and did not involve theestablishment of installations; and 3) no suggestion had been made that Turkey has engaged inoperations involving actual appropriation or other use of the natural resources in question.11 The
Arbitral Tribunal in the Guyana/Suriname case considered that the standard for issuing interim
measures, which is whether a given activity causes irreparable prejudice to the rights of a party,
is more rigorous than the standard for the obligation of self-restraint, which concerns whether acertain activity jeopardizes or hampers the reaching of a final agreement. Therefore, the Tribunal
considered that the decision of the ICJ based on the test of physical damage is relevant in its
6

Arbitral Award Constituted Pursuant to Article 287, and in Accordance with Annex VII, of the United
Nations Convention on the Law of the Sea in the Matter of an Arbitration Between Guyana andSuriname, Award of the Arbitral Tribunal (17 September 2007), Reports of International Arbitral Awards,
Vol. XXX, pp. 131–132 (paras. 465–466).

7

Ibid., p. 132 (para. 467).

8

Ibid., p. 137 (paras. 480–481).

9

Ibid., pp. 132–133 (paras. 468–469).

10

Aegean Sea Continental Shelf Case (Greece v. Turkey), Order of 11 September 1976, ICJ Reports 1976,
pp. 5–6 (para. 2).

11

Ibid., p. 11 (para. 30); Guyana/Suriname Award, supra note 6, p. 132 (para. 468).

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determination of what kinds of activities constitute a violation of the obligation of self-restraint.12
The arbitral award in the Guyana/Suriname case is generally understood to have indicateda cer tain standard, namely, (permanent) physical change to the marine environment, as
permissible limits for unilateral activities in undelimited maritime areas.13 However, some authors
have cautioned against overgeneralization of this standard.14 In particular, it has been pointed
out that even in the context of seismic exploration, the knowledge obtained through exploration
could jeopardize or hamper the reaching of a final agreement or cause irreparable harm to thesovereign rights of another party.15 Moreover, the arbitral award itself was not entirely clear about
the scope of unilateral activities that do not violate the obligation of self-restraint. The award
stated that, as a general rule, unilateral activities that do not cause physical change to the marine
environment “generally” would not violate the obligation of self-restraint.16 However, in its moredetailed findings in relation to the facts of case, the Arbitral Tribunal referred to the fact that bothcountries had given permission for seismic exploration to be undertaken, and that no objections
were raised from the other side. It was on this basis that the award reached its conclusion that,“in the circumstances at hand,” unilateral seismic testing did not violate the obligation of selfrestraint.17 It can be observed that the Arbitral Tribunal did not only take into account the natureof the activity, but also the context of the dispute in the undelimited maritime area, including
the attitudes of the States concerned. This may be regarded as only natural, as the obligation ofself-restraint is concerned with the reaching of a final agreement. However, in contrast to thefact that the award included some general standards concerning the obligation of self-restraint
focused on the nature of the activity, it did not articulate a general framework that reflects all theconsiderations that were taken into account.

(2) Ghana/Côte d’Ivoire Case

The Ghana/Côte dʼIvoire case involved a dispute regarding the delimitation of their territorialseas, EEZs and continental shelves, and unilateral activities under taken by Ghana in thedisputed maritime area pending delimitation. The dispute was referred to the Special Chamberof ITLOS. Ghana had been conducting oil exploration and exploitation activities on the Ghanaianside of the equidistance line in the dispute maritime area. In regard to Ghanaʼs activities, CôtedʼIvoire requested the Special Chamber to “to declare and adjudge that the activities undertaken
unilaterally by Ghana in the Ivorian maritime area constitute a violation of the obligation not tojeopardize or hamper the conclusion of an agreement, as provided for by article 83, paragraph 3,
12

Ibid., p. 133 (para. 469)

13

Yasuhiko Kagami, “Keisō kaiiki de no katsudō ― gaiana tai surinamu kaiyō kyōkai kakutei jiken”[Activities in disputed maritime areas: case concerning the maritime boundar y between Guyana
and Suriname], in Akira Kotera et al. (eds.), Kokusaih hanrei hyakusen [One Hundred SelectedInternational Law Cases] (2nd edition) (Yūhikaku, 2011), p. 77.

14

British Institute of International Comparative Law (BIICL), Report on the Obligation of States under
Articles 74 (3) and 83 (3) of UNCLOS in Respect of Undelimited Maritime Areas (BIICL, 2016), pp. 25–
26; David Anderson and Youri van Logchem, “Rights and Obligations in Areas of Overlapping Maritime
Claims,” in S. Jayakumar et al. (eds.), The South China Sea Disputes and Law of the Sea, (Elgar, 2014), p.
220.

15

Kagami, supra note 13, p. 77; Naoya Okuwaki, “Kyōkai mikakutei kaiiki no kankatsuken” [Jurisdictionin undelimited maritime areas], in Shinya Murase and Junʼichi Etō (eds.), Kaiy ky kai kakutei nokokusaih [International Law of Maritime Boundary Delimitation] (Tōshindō, 2008), p. 173; BIICL,
supra note 14, pp. 25–26; Stephen Fietta, “Guyana/Suriname,” American Journal of International Law,
Vol. 102, No. 1 (2008), pp. 127–128.

16

Guyana/Suriname Award, supra note 6, p. 132 (para. 467).

17

Ibid., p. 137 (para. 481).

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The Obligation of Self-Restraint in Undelimited Maritime Areasof UNCLOS.”18 In addition, Côte dʼIvoire sought provisional measures that would require Ghana,inter alia, to suspend all existing oil exploration and exploitation activities and to refrain from
granting new permits.19
In response to Côte dʼIvoireʼs request for provisional measures, the Special Chamber declined
to order the suspension of ongoing exploration and exploitation activities, and prescribed an orderprincipally requiring Ghana to ensure that no new drilling takes place.20 The Special Chamber
did accept that Côte dʼIvoireʼs rights to explore and exploit resources were at least plausible,that Ghanaʼs ongoing exploration and exploitation activities would result in a modification of thephysical characteristic of the disputed area, and that acquisition and use of information about
the resources of the disputed area would create a risk of irreversible prejudice to the rights
claimed by Côte dʼIvoire.21 However, the Special Chamber considered that an order suspending
ongoing activities would entail the risk of considerable financial loss and could cause harm to themarine environment. It was therefore considered not appropriate to order the suspension of all
exploration and exploitation activities.22
In its judgment on the merits, the Special Chamber found that Ghanaʼs unilateral exploitation
activities were not in violation of the obligation of self-restraint. Firstly, the judgment noted that
Ghana ultimately complied with the provisional measures order and suspended its activities
in the disputed maritime area.23 It added, however, that it would have been preferable if Ghana
had responded to Côte dʼIvoireʼs request at an earlier stage. Secondly, the judgment pointed outthat Ghana had undertaken activities only in the maritime area that was ultimately attributed
to it, and that Côte dʼIvoire had claimed a violation of Article 83(3) of UNCLOS in the “Ivorian
maritime area.”24 In other words, the judgment attached importance to the fact that Côte dʼIvoire
had claimed a violation of the obligation in the Ivorian maritime area, rather than in the disputed
maritime area. As a result of the maritime delimitation effected by the judgment, it was ultimately
found that Ghana had not carried out activities in Côte dʼIvoireʼs waters, and thus there was no
violation of the obligation of self-restraint within the scope of the submission by Côte dʼIvoire. It
seems that this second point was decisive for the judgment in reaching its conclusion. In effect,
the Special Chamber refrained from making substantive decisions concerning the obligation to
exercise self-restraint in the entire disputed maritime area.25
18

Dispute Concerning Delimitation of the Maritime Boundary Between Ghana and Côte d’Ivoire in the
Atlantic Ocean (Ghana/Côte d’Ivoire), Judgment of 23 September 2017, para. 63.

19

Dispute Concerning Delimitation of the Maritime Boundary Between Ghana and Côte d’Ivoire in the
Atlantic Ocean (Ghana/Côte d’Ivoire), Provisional Measures, Order of 25 April 2015, ITLOS Reports
2015, pp. 152–153 (para. 25) (https://www.itlos.org/en/cases/list-of-cases/case-no-23/case-no-23provisional-measures/).

20

Ibid., p. 166 (para. 108). The Special Chamber indicated provisional measures to the effect that:a) Ghana shall ensure that no new drilling takes place in the disputed area; b) Ghana shall take allnecessary steps to prevent information resulting from its exploration activities in the disputed areafrom being used to the detriment of Côte dʼIvoire; c) Ghana shall monitor all activities conducted byitself or with its authorization to ensure the prevention of serious harm to the maritime environment;d) both parties shall cooperate in taking all necessary measures to prevent serious harm to the marine
environment in the disputed area; and e) both countries shall refrain from any unilateral action thatmight aggravate the dispute.

21

Ibid., pp. 163–164 (paras. 88–96).

22

Ibid., pp. 164–165 (paras. 99–102).

23

Ghana/Côte d’Ivoire, Judgment of 23 September 2017, para. 632.

24

Ibid., para. 633.

25

Nuwan Peiris, “Ghana v. Ivory Coast,” American Journal of International Law, Vol. 112, No. 1 (2018), p.
92.

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Nevertheless, the reference to Ghanaʼs suspension of activities in the judgment deser ves
attention. It is not entirely clear in what sense this fact was given as a reason for the findingthat there was no violation of Article 83(3).26 In any event, however, if the Special Chamber had
followed the standard adopted in the Guyana/Suriname case, the fact that Ghana later suspended
drilling activities that would cause physical change to the marine environment could not haveconstituted a reason supporting its conclusion. To that extent, the judgment in the Ghana/Côte dʼIvoire can be regarded as having adopted a different approach from the one in Guyana/
Suriname. A circumstance particular to the case was the fact that there was a certain accumulationof practice using the equidistance line as the boundary for exploration and exploitation of oil
resources, and that a dispute concerning activities in the Ghanaian side of the equidistance line
had surfaced relatively recently. (However, the argument of Ghana that mutual practice reflected
a tacit agreement between the parties on the maritime boundary was not accepted by the Special
Chamber.)27 The focus on the “suspension” of the activities carried out in the disputed maritime
area and not on factors such as the nature of the activities that were carried out, could be because
consideration was given to the particular context of the dispute between the parties.
Judge Paik appended a separate opinion to the judgment. Judge Paik, while stating thatthe formulation of the submission of Côte dʼIvoire compelled him to support the judgment,
considered the arguments on the obligation of self-restraint in detail.28 According to Judge Paik,
the obligation of self-restraint is a “result-oriented notion,” and the key is whether the action inquestion would have the effect of endangering or impeding the reaching of a final agreement.29
He maintains that, contrary to the approach adopted by the Guyana/Suriname award, what ispermissible under Article 83(1) and what is not cannot be identified in general and in the abstract.
Rather, Judge Paik considers it is necessary to take into account such factors as the type, nature,
location, and the time of acts, as well as the manner in which they are carried out, and to decidein the framework of relations between the State concerned.30 With regard to the case at hand,
he concluded that there was a violation of the obligation of self-restraint by Ghana, as Ghana had
continued to carry out highly invasive activities in the vicinity of the equidistance line, despite
repeated protests by Côte dʼIvoire.31(3) Assessment of the International Case Law
The two cases so far decided by international courts and tribunals, relating to the obligation ofself-restraint, do not necessarily provide clear standards concerning the scope of the obligation.
The Guyana/Suriname case indicated a test of physical change to the marine environment, andits decision that exploratory drilling and exploitation are not to be permitted is considered as

26

For a view that the reasoning is unconvincing, see Nigel Bankes, “ITLOS Judgment in the Maritime
Boundary Dispute between Ghana and Côte dʼIvoire” (http://site.uit.no/jclos/files/2017/10/JCLOSBlog_271017_ITLOS-Judgment-in-the-Maritime-Boundar y-Dispute.pdf). Bankes points out that the
obligation of self-restraint existed before and independently of the provisional measures order, and even
if Ghana could put an end to its continued violation of the obligation of self-restraint by complying withthe order, this does not mean that there was no proven breach before that time.

27

It is also noteworthy that the judgment referred to the issue as whether there was a breach of theobligation of self-restraint “after realizing that that area was also claimed by Côte dʼIvoire.” Ghana/Côted’Ivoire, Judgment of 23 September 2017, para. 631.

28

Ghana/ Côte d’Ivoire, Judgment of 23 September 2017, Separate Opinion of Judge Paik, para. 1.

29

Ibid., para. 6.

30

Ibid., para. 10.

31

Ibid., para. 16.

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providing important guidance on the matter.32 However, the view that activities that do not cause
physical change are generally permissible has not received support in subsequent discussions
on this issue. It has been suggested in academic literature that a flexible approach taking into
account the context of the relations between the States concerned may be necessary, and that it
may be difficult to establish an absolute standard based on the nature of the activity in question.33
As noted above, the reference to the suspension of existing exploitation activities in the judgmentin the Ghana/Côte dʼIvoire case may be regarded as consistent with this kind of approach. Thatjudgment also emphasized that the obligation of self-restraint is an obligation to make ever yeffort not to jeopardize or hamper the reaching of a final agreement, “in a spirit of understanding
and cooperation.”34 It could be argued that such an understanding of the obligation of selfrestraint also implies that there are certain limits to categorical standards based on the nature of
the activity in question.
The provisional measures order in the Ghana/Côte dʼIvoire case is also indicative of the limitsof the approach, such as in the Guyana/Suriname award, that attempts to identify the scope of theobligation of self-restraint through an analogy with the jurisprudence on provisional measures.
Since unilateral exploitation activities by Ghana resulted in permanent physical change to theseabed, this would be considered a violation of the obligation of self-restraint, if the standard
in Guyana/Suriname was adopted. In light of this, concerns have been raised about the factthat the Special Chamber in the Ghana/Côte dʼIvoire case did not prescribe orders for existing
exploratory drilling and resource exploitations, pointing out that there is a risk of a fait accompli
being accomplished.35 However, it could also be argued that the decision concerning provisional
measures in the Ghana/Côte dʼIvoire case has simply demonstrated that decisions on provisional
measures are made under different circumstances from those on the obligation of self-restraint inundelimited maritime areas. While no fundamental resolution of the situation is anticipated in thenear future with respect to the obligation of self-restraint, provisional measures are prescribed
only taking into account the need to preserve rights and prevent the exacerbation of the dispute
until the judgment on the merits is rendered.36 Thus, it may be time for a reassessment of thestandard adopted in Guyana/Suriname, also from the viewpoint of the reasoning from which it
was deduced.
One issue not addressed in either of these cases is the question of the geographical scope ofthe obligation of self-restraint. In both cases, the States concerned had clear claims regarding
their maritime zones. However, in areas such as the East China Sea, where such clear-cut claims
to maritime areas have not been made, the identification of a disputed area is in itself a difficult
issue. If the obligation of self-restraint is considered applicable to the entire area of overlapping
maritime entitlements, coastal States that make excessive maritime claims may be placed at anadvantage. It has therefore been suggested that defining the geographical scope of the obligationof self-restraint may not be necessary, and that considerations should instead focus on the extent
32

Kazuhiro Nakatani, “Kyōkai mikakutei kaiiki ni okeru ippōteki shigen kaihatsu to buryoku ni yoru
ikaku―gaiana-surinamu chūsai hanketsu wo sankō toshite” [Unilateral resource development and thethreat of force in undelimited maritime areas: A case study of the Guyana/Suriname arbitral award], inShunji Yanai and Shinya Murase (eds.), Kokusaih no jissen―komatsu ichir taishi tsuitou [The Practiceof International Law: in memory of Ambassador Ichirō Komatsu] (Shinzansha, 2015), p. 534.

33

Anderson and Logchem, supra note 14, pp. 206–207; BIICL, supra note 14, pp. 24–25.

34

Ghana/Côte d’Ivoire, Judgment of 23 September 2017, paras. 629–630.

35

Yoshifumi Tanaka, “Unilateral Exploration and Exploitation of Natural Resources in Disputed Areas: A
Note on the Ghana/Côte d’Ivoire Order of 25 April 2015 before the Special Chamber of ITLOS,” Ocean
Development and International Law, Vol. 46 (2015), pp.326–327.

36

The separate opinion of Judge Paik in the Ghana/Côte dʼIvoire case also makes this point. Ghana/Côted’Ivoire, Judgment of 23 September 2017, Separate Opinion of Judge Paik, paras. 8–9.

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to which a unilateral activity jeopardizes or hampers the reaching of a final agreement.37 However,this issue has not received adequate discussion in academic literature, making it difficult toconsider the application of the obligation of self-restraint in the East China Sea.

2. Responses to Violations of the Obligation of Self-Restraint
In addition to the question of the kinds of unilateral activities that would constitute a violation ofthis obligation, another important question is the scope of permissible responses by a coastal
State against a violation of the obligation of self-restraint by another State. Coastal States are ata risk of being placed at a disadvantage in the ultimate maritime boundary delimitation if they
fail to respond to unilateral activities undertaken by another State, as this may be deemed tacit
acceptance of the maritime claim of the latter. On the other hand, coastal States must ensure that
their own responses do not violate the obligation of self-restraint, if they choose to take certain
measures in response to a violation.

(1) Law Enforcement against Violations of the Obligation of Self-Restraint
In the Guyana/Suriname case, one of the main issues concerned the CGX Incident, in whicha drilling rig operating under permission from Guyana was ordered to leave the area by the
Surinamese navy. The Arbitral Tribunal, in addition to finding that Guyanaʼs grant of permission
for explorator y drilling constituted a violation of the obligation of self-restraint, decided thatthe order to leave issued by the Surinamese navy constituted a threat of force prohibited under
Article 2(4) of the UN Charter, and also violated the obligation of self-restraint under UNCLOS.38
In finding that Suriname had violated the obligation of self-restraint, the arbitral award specifically
noted that Suriname had other peaceful options to address the issue, including negotiations andthe use of the compulsory dispute settlement mechanism.39 The finding by the Arbitral Tribunal
in this case that the order to leave by the Surinamese navy constituted a threat of force in violationof Article 2(4) of the UN Charter has drawn some criticisms, sparking a debate concerning
the conceptual distinction between the use of force in maritime law enforcement and under the
UN Charter.40 In relation to the obligation of self-restraint, it is not clear from the arbitral award
itself whether law enforcement measures that do not constitute the threat or use of force would
be found to constitute a breach, as the finding that Suriname had violated the obligation of selfrestraint in this case was made in connection with the finding on the threat of force.
However, considering that law enforcement activities in undelimited maritime areas canraise tensions between the States concerned, the statement by the arbitral award in the Guyana/
Suriname case that States should resort to peaceful means of dispute settlement should equally
apply to law enforcement activities in general. On the other hand, some adopt the view thatthe obligation of self-restraint should not necessarily prohibit all law enforcement measures,for the reason that it is doubtful whether negotiations and dispute settlement procedures are
sufficient measures to protect the interests of the coastal State after another States actually starts

37

BIICL, supra note 14, pp. 29–31.

38

Guyana/Suriname Award, supra note 6, pp. 126, 138 (paras. 445, 483–484).

39

Ibid., p. 138 (para. 484).

40

Patricia Jimenez Kwast, “Maritime Law Enforcement and the Use of Force: Reflections on theCategorization of Forcible Action at Sea in the Light of the Guyana/Suriname Award,” Journal ofConflict and Security Law, Vol. 13, No. 1 (2008), pp. 49–91; Tom Ruys, “The Meaning of ʻForceʼ and theBoundaries of the Jus ad Bellum: Are ʻMinimalʼ Uses of Force Excluded from UN Charter Article 2 (4),”American Journal of International Law, Vol. 108, No. 2 (2014), pp. 159–210.

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conducting unilateral activities.41 This question is linked to the issue of whether it is possible toutilize the compulsory dispute settlement procedure of UNCLOS for a violation of the obligationof self-restraint, which is discussed below. It has also been suggested that even if law enforcement
activities in undelimited maritime areas would in general violate the obligation of self-restraint,
they may be justified as countermeasures against the prior violation of the obligation by anotherState.42 It would seem unequitable for a State to be placed at a disadvantageous position due
to the mutual obligation of self-restraint, while another State engages in unilateral resource
development. Thus, there might be room to consider that, under exceptional circumstances suchas in case of urgency or where there is no other way to preserve its rights, States could respondby certain law enforcement measures without violating the obligation of self-restraint.

(2) The Possible Use of the Compulsor y Dispute Settlement Mechanism
As discussed above, the arbitral award in the Guyana/Suriname case is of the view that an option
for States is to resort to the dispute settlement mechanism under UNCLOS when disputes arise
in undelimited maritime areas. However, Article 298(1)(a) of the Convention allows States todeclare that they do not accept procedures with respect to “disputes concerning the interpretation
or application of articles 15, 74 and 83 relating to sea boundary delimitations,” and therefore to
remove themselves from the scope of the compulsory dispute settlement procedure for thesekind of disputes. Of Japanʼs neighbors, Russia, the Republic of Korea and China have issued
such declarations with respect to all categories of disputes provided under Article 298(1).43 If
disputes concerning the obligation of self-restraint, which is provided in Article 74(3) and 83(3),are considered to fall within the exception under Article 298(1)(a), disputes with these Statesconcerning a violation of the obligation of self-restraint cannot be brought to the compulsory
dispute settlement procedure under UNCLOS.
One view on this issue is that disputes concerning the obligation of self-restraint do not fallwithin the exception on disputes “relating to sea boundary delimitations,” since the exception
should not be interpreted in an unduly broad manner, considering that the general rule of
UNCLOS is to subject disputes concerning its interpretation and application to the compulsory
dispute settlement procedure.44 However, the fact that Article 298(1)(a) provides an exception
should not necessarily warrant a narrow reading. A better approach is to consider the intended
scope of the exception on the basis of the treaty provision itself.
That being said, the text of Article 298(1)(a), which should provide the starting point forthis discussion, is ambiguous as to its purpose. It is unclear whether the intent was simply toallow exclusion of “disputes concerning the interpretation or application of articles 15, 74 and83,” with the phrase “relating to sea boundar y delimitations” merely explaining the content
of the referenced articles, or rather, to specifically limit the exclusion to disputes “relating
41

Irini Papanicolopulu, “Enforcement Action in Contested Waters: The Legal Regime,” 6th IHO-IAG
ABLOS Conference, Contentious Issues in UNCLOS―Surely Not?, Monaco, 25–27 October, 2010, p. 4
(https://www.iho.int/mtg_docs/com_wg/ABLOS/ABLOS_Conf6/S7P2-P.pdf)

42

BIICL, supra note 14, p. 116, 172; Sōji Yamamoto, “Kyōkai mikakutei kaiiki ni okeru hōshikkō sōchi
no haikei to genkai” [The Context and Limits to Law Enforcement Measures in Undelimited Maritime
Areas], Kaiy h no shikk to tekiy wo meguru kokusai funs jirei kenky [Case Studies of International
Disputes Concerning the Enforcement and Application of the Law of the Sea] (Kaizyō hoantaisei tyōsakenkyū iinkai hōkokusyo [Report of the Research Committee on the Regime of Maritime Security])(Japan Coast Guard Foundation, 2008), p. 113.

43

Russian Federation: Declaration made upon ratification, Law of the Sea Bulletin, No. 34 (1997), p. 9;
Republic of Korea: Declaration pursuant to Article 298, 18 April 2006, Ibid., No. 61 (2006), p. 14; China:
Declaration under Article 298, 25 August 2006, Ibid., No. 62 (2006), p. 14.

44

Nakatani, supra note 32, p. 534.

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Kentaro Nishimoto

to sea boundar y delimitations ” within the broader categor y of “ disputes concerning theinterpretation or application of articles 15, 74 and 83.”45 As a matter of textual interpretation, theformer interpretation seems more straightforward. This was the interpretation adopted in thedecision on competence in the compulsory conciliation proceedings between Timor-Leste andAustralia concerning the Timor Sea in 2016.46 According to this position, disputes concerning
the obligation of self-restraint are not subject to compulsor y dispute settlement procedures,
because disputes concerning paragraph 3 of Articles 74 and 83 which provide the obligation ofself-restraint would clearly fall within “disputes concerning
articles 15, 74 and 83,” which are
excluded by Article 298(1)(a).
However, the decision by the conciliation commission was not suppor ted by detailed
reasoning, and the matter may still be considered open for further discussion. It is understoodthat the reason for having a system of optional exceptions in the first place is that some disputes
were considered politically sensitive to be entrusted to the compulsor y dispute settlement
procedure.47 Article 298(1)(a), in particular, reflects the political and economic importance ofmaritime boundary delimitation, as a process for determining the scope of the power of coastal
States.48 It is possible to argue that this rationale for allowing optional exceptions does not apply
with respect to disputes concerning the obligation of self-restraint, as the dispute would haveno bearing on the standards or methods for boundar y delimitation itself.49 However, it could
alternatively be argued that disputes concerning the obligation of self-restraint cannot always
be considered in complete isolation from the standards and methods for the final maritime
delimitation, as the plausibility of the rights may have to be taken into account in finding a
violation of the obligation of self-restraint.

Conclusions
In academic circles, discussions are still ongoing about the scope of unilateral activities that canbe carried out by coastal States without violating the obligation of self-restraint in undelimited
maritime areas, and the measures that can be taken by coastal States against unilateral activities
that violate the obligation of self-restraint. A consistent standard has not yet been developed in thejurisprudence of international courts and tribunals. The arbitral award in the Guyana/Suriname
case did establish a seemingly clear-cut standard concerning the limits of unilateral activities.
However, the limits to making categorical determinations based on the nature of the activity havecome to be recognized as a result of the subsequent academic debates and the judgment in the45

Van Logchem, supra note 5, p. 195.

46

In the Matter of a Conciliation before a Conciliation Commission Constituted under Annex V to theUnited Nations Convention on the Law of the Sea between the Democratic Republic of Timor-Lesteand the Commonwealth of Australia, Decision on Australiaʼs Objections to Competence (19 September2016), paras. 93–97. This case was a compulsory conciliation case under UNCLOS Annex V, which canbe initiated at the request of a party, when a dispute that fall under the optional exception in Article
298(1)(a) “arises subsequent to the entry into force of this Convention and where no agreement withina reasonable period of time is reached in negotiations between the parties.” On the decision of theconciliation commission on its competence, see Dai Tamada, “Kokuren kaiyōhō jōyaku fuzokusho V
chōtei jiken (higashi chimōru/ōsutoraria) kengen kōben ni kansuru kettei (2016 nen 9 gatsu 19 nichi)”[UNCLOS Annex V conciliation case (Timor-Leste/Australia), Decision on Objections to Competence(19 September 2016)], Kobe h gaku zasshi [Kobe Law Journal], Vol. 66, No. 3–4 (2017), pp. 119–134.

47

Proelss, supra note 4, p. 1921.

48

Natalie Klein, Dispute Settlement in the UN Convention on the Law of the Sea (Cambridge University
Press, 2005), p. 257.

49

Yumi Nishimura, “Kaiyō funsō no kaiketsu tetsuzuki to hō no shihai” [Dispute settlement procedures
concerning maritime disputes and the rule of law], Kokusai Mondai [International Affairs], No. 666(2017), p. 42.

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more recent Ghana/Côte dʼIvoire case.
In the developments after the Guyana/Suriname case, the obligation of self-restraint isincreasingly viewed as an obligation not limited to refraining from certain specific types ofactivities that could be identified in general and in the abstract. This is a useful point of reference
in examining the current situation in the East China Sea. For example, by restricting its resource
development in the East China Sea to the Chinese side of the equidistance line, China may be
acting in the belief that it is in compliance with the obligation of self-restraint by simply doing so.
However, notwithstanding the possible differences of interpretation concerning the geographicalscope of the obligation of self-restraint, the fact that China has continued to pursue unilateraldevelopment, despite the understanding on joint development that was reached in June 2008,
takes on added significance in the context of Japan-China relations in the East China Sea.50 On theother hand, it is also important for Japan to reassess whether activities conducted on the Japaneseside of the equidistance line would not have the effect of jeopardizing or hampering the reachingof a final agreement based on “the spirit of understanding and cooperation.”
It is dif ficult to provide any concrete conclusions on the prospect of Japan initiatingproceedings against China using the dispute settlement mechanism under UNCLOS, with theclaim that the unilateral resource development activities by China violate the obligation of selfrestraint. As discussed above, precedents and academic discussions on this point are limited,making it difficult to draw any concrete conclusions. However, it would seem that a plausible
case could be made in favor of the interpretation that Ar ticle 298(1)(a) does not exclude
disputes concerning a violation of the obligation of self-restraint from the compulsory disputesettlement procedure. As such, this option should not necessarily be ruled out. On the other
hand, the question of whether invoking the dispute settlement mechanism could contribute to
the resolution of the dispute in reality is an issue that must be seriously considered on its own
merits.51

50

Ministry of Foreign Affairs of Japan, “Japan-China Joint Press Statement Cooperation between Japanand China in the East China Sea” (https://www.mofa.go.jp/files/000091726.pdf).

51

On this point, see Nishimura, supra note 49, pp. 41–45.

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