North Sea Continental Shelf Case Summary

CASE TITLE

Federal Republic of Germany v. Kingdom of Denmark; Federal Republic of Germany v. Kingdom of the Netherlands

CITATION

North Sea Continental Shelf Cases, Judgment, I.C.J. Reports 1969, p. 3

COURT 

International Court of Justice (ICJ)

BENCH 

The case was heard by the full bench of the International Court of Justice, which included President Bustamante y Rivero, Vice-President Koretsky, and Judges Sir Gerald Fitzmaurice, Tanaka, Jessup, Morelli, Sir Muhammad Zafrulla Khan, Padilla Nervo, Forster, Gros, Ammoun, Bengzon, Petren, Lachs, and Onyeama.

Judges ad hoc were Hermann Mosler for Germany and Max Sørensen for both Denmark and the Netherlands. The Registrar was Aquarone. 

DATE OF JUDGMENT 

20 February 1969 

RELEVANT STATUTES

1. Article 6 of the 1958 Geneva Convention on the Continental Shelf (describes the equidistance principle for marking maritime boundaries between neighbouring states).
2. Articles 38(1)(b) and (c) of the Statute of the International Court of Justice (which discuss international customs and general legal principles).
3. Truman Proclamation
4. Additional factors included developing norms of customary international law, and the judgment anticipated fundamental principles later included in the 1982 United Nations Convention on the Law of the Sea (UNCLOS), especially Articles 74 and 83 about fair maritime delimitation.

BRIEF FACTS 

The water of the North Sea is shallow, with a continental shelf of depth of less than 200 metres. The North Sea Continental Shelf Case involved a legal dispute between the Federal Republic of Germany and two of its maritime neighbours, Denmark and the Netherlands. These nations, unable to come to a consensus on the prolongation of partial boundaries, were arguing about the division of their respective continental shelves in the North Sea. Denmark and the Netherlands wished the prolongation to be effected based on the “equidistance principle.” The Federal Republic of Germany objected to the delimitation method, arguing that using the equidistance rule would unduly curtail its proper share of the continental shelf area. The contested seabed contained valuable resources, including oil and gas. Germany asserted that, considering the unique concave shape of its coastline, with a recessing coast, the delimitation of its shelf based on the equidistance method will lead to an unfair result. If a line from the boundary is pulled inwards in the direction of the concavity and then 2 equidistance lines are drawn, the lines inevitably meet at a relatively shorter distance from the coast, thereby “cutting off” the coastal State from the area of the continental shelf outside. Whereas Denmark and the Netherlands, with an outwardly curving convex coast, cause the equidistance lines to leave the coasts on divergent courses, therefore bearing a widening tendency on the area of the continental shelf off that coast. The Federal Republic of Germany argued that the delimitation should be based on fair principles, considering the natural extension (concavity) of its land and the unique shape of its coastline, rather than rigidly applying the principle of equidistance. The countries had signed partial agreements but sought the ICJ’s help to resolve their remaining claims. 

The image is attached below for ease of understanding.

Figure 1: Equidistance lines in the North Sea (Source: Sovereign Limits)

ISSUES INVOLVED 

The main issues before the International Court of Justice were complex

1. Whether Article 6 of the 1958 Geneva Convention on the Continental Shelf of 1958, which requires the equidistance method for delineating continental shelves, applied to Germany, which was not a party to the Convention.
2. Whether the equidistance principle had become a binding norm of customary international law that applied to all states, regardless of treaty involvement.
3. Whether Germany’s past actions amounted to acceptance or waiver, thus binding it to the equidistance rule.
4. The Court needed to establish the general principles for fairly delimiting continental shelf boundaries under international law.

ARGUMENTS 

The Federal Republic of Germany’s argument rested on three main points: its lack of participation in the 1958 Geneva Convention, the non-customary nature of the equidistance rule, and the geographical disadvantages stemming from its concave coastline. It stated that the correct rule is that each of the States concerned shall have a “just and equitable” share of the available continental shelf. Germany argued that in a sea shaped such as the North Sea, each State was entitled to a continental shelf area extending up to the central point of the sea, or at least extending to its median line. It should not be held to a treaty it did not sign, and Article 6 of the Geneva Convention had not yet become customary international law, therefore not applicable as such between the Parties. It claimed that strictly following the equidistance rule in case of the configuration of the North Sea would unfairly limit its share of the continental shelf due to its coastline’s shape, therefore not leading to a just and equitable apportionment. Germany promoted an approach based on fair principles, insisting that the proportion of coastlines should guide the process as the unique shape of the coastline constituted a special circumstance, thereby departing from the method of delimitation.

Conversely, Denmark and the Netherlands defended equidistance as both a treaty requirement and a customary practice. They highlighted that the matter was governed by a mandatory rule of law and the widespread state behaviour, because the use of such a method is not merely a conventional obligation, but a critical part of the corpus of public international law, and argued that equidistance brought legal clarity and predictability to maritime boundary setting. They took the defence of Article 6 of the Geneva Convention on Continental Shelf (Equidistance – special circumstances) rule, which states the following, “in the absence of an agreement by the parties to employ another method, all continental shelf boundaries had to be drawn by mean of an equidistance line unless special circumstances were recognised.” They stated that the configuration of the German North Sea Coast did not itself constitute a special circumstance. They also claimed that Germany had, through its conduct and earlier negotiations, implicitly accepted the validity of equidistance and should not be allowed to dispute it now. According to them, permitting Germany to depart from equidistance would undermine established norms and create chaos in maritime boundary making. 

JUDGMENT 

• Apportionment Theory was rejected

The ICJ dismissed the claim that Germany was bound by Article 6 of the Geneva Convention. The Court explained that Germany, as a non-signatory, could not be legally held to a treaty it had not ratified. Importantly, the Court also rejected the idea that the equidistance principle had become part of customary international law, stating that the duration is not as important as widespread and representative participation, and uniform usage. The Court highlighted an important difference between ‘delimitation’ and ‘apportionment’. It clarified that the issue at hand was that of delimitation, meaning the drawing of boundaries between areas already assigned to states, with existing sovereign rights. In contrast, apportionment would suggest the distribution of undivided common territory or res communis, which presupposes undivided entitlement to the single resource, in this case, the naturally prolonged continental shelf. This distinction was key in reinforcing the idea that legal rights to the continental shelf arise naturally from its topography and do not depend on negotiated distribution. This rejection of the apportionment theory strengthened the ICJ’s understanding of maritime law based on sovereign rights from natural extension.

• Non-applicability of Article 6 of the 1958 Continental Shelf Convention

Denmark and the Netherlands argued that the Convention, particularly Article 6, is binding on the Federal Republic through its conduct, public statements, and proclamations. Having unilaterally assumed the obligations of the convention and generally recognising it as applicable to the delimitation. The Court observed that “only a very definite, very consistent course of conduct” on the part of the State would justify the Court in upholding, more so because the Federal Republic had not ratified the convention. Only when States express their intention to be bound by the convention by way of ratification and accession can it be presumed that the State is bound by the rules and thus obligated to follow them. The Federal Republic, although at all times fully able and entitled, had not carried out the formalities of ratification to be bound by the convention, thereby no real intention existed on its part as to be bound by the regime of the convention. The Court also observed that even if the Federal Republic had ratified the treaty, it had the option of entering into a reservation on Article 6, by virtue of which the particular article would no longer be obligatory on Germany.

• Equidistance Principle not inherent in the basic doctrine of the Continental Shelf

Denmark and the Netherlands argued that the Federal Republic of Germany was bound to accept the delimitation based on the equidistance principle since the use of this method was a rule of general/customary international law, therefore automatically binding upon Germany. The court accepted that the rights of the coastal state to its continental shelf area were based on its sovereignty over the land domain of which the shelf area was the natural prolongation under the sea, hence the rights existed ipso facto and ab initio. The court relied on the proximity as the test of appurtenance, equated with adjacency that is all those parts of shelf being considered appurtenant to a particular State coast, which were closer to it than they were to any point on the coast of any other State, therefore delimitation has to be effected by a method which would leave to each of the States concerned all those areas that were nearest to its coast, which only equidistance lines would be able to do, hence this method stands valid.

• Equidistance Principle Not a Rule of Customary International Law

The question that arose was whether, through positive law processes, the equidistance principle must now be regarded as a rule of customary international law. The Court stated that the principle of equidistance, as articulated in Article 6 of the Geneva Convention, was not proposed by the International Law Commission as an emerging rule of customary international law. It is indispensable that the State Practice during that period, including that of States especially affected, should be both extensive and virtually uniform as to show a general recognition that a rule of law has evolved. Since in the present case, there was no evidence of any legal compulsion (inconclusive and insufficient evidence), the Court highlighted that the Geneva Convention was not originally declaring any mandatory rule of customary international law enjoining the use of the equidistance principle; therefore, it is not a State Practice.

• Principles and Rules of Law Applicable

The court took to indicate to the Parties the principles and the rules of law in the light of which delimitation was to be effected. The Truman Proclamation states that the delimitation must be an object of agreement between the States concerned and must be arrived at following equitable principles. Applying the equitable principles, the equidistance method could lead to inequality. The Court stated that no other single method of delimitation was obligatory, and delimitation is to be effected by agreement per equitable principles. The methods must be applied so as to leave as much as possible to each Party, all those parts of the Continental shelf that constitute a natural prolongation of the land, without encroaching on the natural prolongation of the land of the other. If the areas coincide, then the areas are to be divided between the Parties in agreed proportions, failing which the areas are to be divided among them equally. The Parties entering into negotiations must take into account

1. General configuration of the coasts,
2. Presence of any special or unusual features, so far known or ascertainable.
3. Natural resources of the shelf
4. Length of the shelf in the general direction of the coastline
5. Degree of proportionality as to the area appertaining to each State
6. Physical and geographical structures

RATIO DECIDENDI

1. Equity over Equidistance

This judgment established that equidistance is not mandatory under customary international law. The Court said that states with neighbouring coasts must agree on maritime boundaries based on fair and equitable principles. These principles call for considering all relevant factors, such as geographical circumstances, to reach a fair outcome. This decision moved away from using equidistance at the first instance, favouring a more flexible approach to resolving maritime boundary disputes based on fairness. It marks a shift from simply applying geometric formulas to a more thoughtful method based on fairness. The Court’s analysis showed that state practice on equidistance was inconsistent and that there was no belief that this practice was legally required. Therefore, equidistance could not be seen as a customary norm.

The Court also explained that the legal nature of the continental shelf is a natural extension of a coastal state’s land territory. This interpretation was based on the idea that a coastal state’s legal rights to the continental shelf exist by their very nature and from the start, without needing occupation or a formal declaration. This perspective further supported the need for fair solutions that consider natural geography, rather than just technical measures like equidistance.

2. State Practice

This covers any act of the State from which views about customary law may be inferred. It is reflective of how the States behave in practice that forms the basis of customary law. Claims and conventions of states have been adduced as evidence of State Practice.

3. Opinio Juris

The belief that the State activity is legally obligatory is the factor that turns usage into a custom and renders it part of the rules of international laws, reflected through acts (Nicaragua) and omissions (Lotus). It states that the party which relies on a custom of this kind must prove that such a custom was established in such a manner that it has become binding on the other party, that it is in accordance with

1. A constant and uniform usage
2. Practice by States in question
3. Such usage is the expression of a right appertaining to the State
4. A duty incumbent on the territorial State

Para 77: “….To achieve this result, two conditions must be fulfilled. Not only must the acts concerned amount to a settled practice, but they must also be such, or be carried out in such a way, as to be evidence of a belief that this practice is rendered obligatory by the existence of a rule of law requiring it. The need for such a belief, i.e., the existence of a subjective element, is implicit in the very notion of the opinio juris sive necessitatis. The States concerned must therefore feel that they are conforming to what amounts to a legal obligation. The frequency, or even habitual character of the acts, is not in itself enough. There are many international acts, e.g., in the field of ceremonial and protocol, which are performed almost invariably, but which are motivated only by considerations of courtesy, convenience or tradition, and not by any sense of legal duty.”

It is the process whereby States behave in a certain way in the belief that such behaviour is law or is becoming a law, thereby customary law is established by virtue of a pattern of claim, absence of protests by States particularly interested in the matter at hand, and acquiescence by other States.

OBITER DICTA

The Court made several significant remarks that continue to shape the law of the sea. It acknowledged that while equidistance is not obligatory and binding upon the States, it can still be suitable in many cases, especially in situations where the coastlines are regular and no special circumstances exist. This recognition maintained equidistance as a useful method under suitable and fair conditions.

Second, the Court highlighted an important difference between ‘delimitation’ and ‘apportionment’. It clarified that the issue at hand was that of delimitation, meaning the drawing of boundaries between areas already assigned to states, with existing sovereign rights. In contrast, apportionment would suggest the distribution of undivided common territory or res communis, which presupposes undivided entitlement to the single resource, in this case, the naturally prolonged continental shelf. This distinction was key in reinforcing the idea that legal rights to the continental shelf arise naturally from its topography and do not depend on negotiated distribution.

Third, the Court cautioned against the assumption that treaty provisions automatically become customary law. It stressed that for a treaty rule to turn into customary law, it must go hand in hand with general practice and opinio juris. This statement remains a fundamental guide for understanding the connection between treaty law and customary international law.

FINAL DECISION

The ICJ observed that Germany was not bound by Article 6 of the 1958 Geneva Convention and that the equidistance principle had not become customary law. Germany was not prevented from challenging equidistance. The Court stated that the delimitation of the continental shelf should be applied through an agreement based on fair principles, considering all relevant circumstances. The decision did not set the boundary itself but established the legal framework to guide future negotiations.

The ruling supported a fairer division of the continental shelf and was a significant win for Germany. It avoided the limiting outcome of equidistance, which would have unfairly restricted its continental shelf because of the shape of its coast. By rejecting the strict use of the equidistance principle and accepting fair principles, the ICJ opened the door for more balanced and just methods in boundary setting. The main reasoning emphasized the importance of fairness in international law. Meanwhile, the additional comments offered helpful insights into how customs change and the significance of geography and legal context in international conflicts. The case’s influence continues in the principles outlined in the United Nations Convention on the Law of the Sea and in the court’s decisions on later maritime boundary cases. It serves as a key example for understanding how international law changes to maintain fairness in complex and varied geographical situations. The case remains a key moment in the development of maritime law and still affects maritime boundary disputes worldwide.