Legal Characterization of the Second Thomas Shoal in the South China Sea Arbitral Award: A Critical Analysis

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2024-01-26 | Zheng Zhihua

Recently, in diplomatic démarches or statements regarding the Second Thomas Shoal (also known as Ren'ai Jiao in China; Ayungin in the Philippines), the Philippines has repeatedly stressed  that “Ayungin Shoal is not an island; it is a low-tide elevation that cannot be appropriated or subjected to sovereignty claims. Ayungin Shoal is located 106.3 nautical miles from the Philippine Island of Palawan. On the other hand, Ayungin Shoal is 423.30 NM from the Paracel’s, and 617.39 NM from the Chinese mainland - clearly beyond the 200 NM maximum maritime entitlement for an EEZ under UNCLOS. In accordance with UNCLOS and the final and binding 2016 Award in the South China Sea Arbitration, Ayungin Shoal is ‘within the exclusive economic zone and continental shelf of the Philippines,’ over which the Philippines has sovereign rights and jurisdiction. China cannot, therefore, lawfully exercise sovereignty over it."[1]


Similarly, in its statement of support for the Philippines' South China Sea claims, the US also underlined that "Second Thomas Shoal is a feature well within the Philippine exclusive economic zone and on the Philippine continental shelf. An international tribunal’s July 2016 decision – legally binding on both the Philippines and PRC – made clear that 'there exists no legal basis for any entitlement by China to maritime zones in the area of Second Thomas Shoal.'  The same ruling affirmed that Second Thomas Shoal is a low-tide elevation outside the territorial sea of another high tide feature – as such, the PRC’s territorial claims to it are unfounded."[2] 


These statements pivot on the contested premise that the South China Sea Arbitration ruling categorizes Second Thomas Shoal as a low-tide elevation.[3] But is Second Thomas Shoal truly a low-tide elevation?[4] What specific evidence formed the basis of this conclusion?  Are these pieces of evidence  admissible, relevant, and sufficient under the established rules of international adjudication? Additionally, did the Tribunal apply the appropriate standard of proof – “preponderance of evidence” or “proof beyond reasonable doubt” – in reaching this determination?[5] In particular, are they capable of satisfying the requirements of Article 9 of Annex VII to the United Nations Convention on the Law of the Sea (UNCLOS), thus ensuring that the arbitral award is well founded in fact and law? 

According to the definition in Article 13 of UNCLOS, a low-tide elevation is a naturally formed area of land which is surrounded by and above water at low tide but submerged at high tide. The Award's determination of Second Thomas Shoal as a low tide elevation, a key finding, rests on a limited evidentiary foundation. Contained within just three paragraphs (paragraphs 379-381) and totaling 454 words, the conclusion primarily relies on two documents: the 1944 British "Sailing Directions for the Dangerous Ground"[6] and the 2011 Chinese "China Sailing Directions: South China Sea (A103).[7] Unpacking the evidentiary puzzle: This paper offers a critical analysis of paragraphs 379-381 of the Arbitral Award, focusing on their role in the determination of Second Thomas Shoal's legal status. The established rules of evidence will be employed  to assess the relevance, admissibility, and persuasive power of the presented materials, ultimately questioning their sufficiency in meeting the required standard of proof.[8]

First, the two pieces of evidentiary material are not competent evidence.[9] As the International Court of Justice stated in the Territorial and Maritime Dispute between Nicaragua and Colombia, "Those charts were prepared in order to show dangers to shipping at ……(area), not to distinguish between those features which were just above, and those which were just below, water at high tide."[10] The Arbitral Tribunal was fully aware that the function of nautical survey reports, sailing directions and charts is to aid navigation, with the aim of guaranteeing the safety of navigational operation,[11] and not to be used for the purpose of identifying the nature and legal status of maritime features and distinguishing between islands, reefs, low-tide elevations and submerged features. 

The Arbitral Tribunal was also clearly aware that "as a general matter, the most accurate determination of whether a particular feature is or is not above water at high tide would be based on a combination of methods, including potentially direct, in-person observation covering an extended period of time across a range of weather and tidal conditions."[12]

However, the ruling rendered its finding solely by using "navigation guides".  Given the function of navigation guides, which by their very nature are inherently designed for practical seafaring, they might at best serve as supplementary information for determining the nature of maritime features, but should not serve as the main evidence, and certainly not as the sole basis.

Moreover, the Royal Navy's 1944 Sailing Directions for the Dangerous Ground , published more than 70 years ago, is clearly that the probative value of age-old material is questionable. As the International Court of Justice has rightly pointed out that what is relevant to the issue before it is the contemporary evidence and not nautical guides and surveys from many years or decades ago.[13]

Second, the two “navigation guides” relied upon by the ruling do not constitute sufficient evidence. The tribunal knew that Second Thomas Shoal was poorly charted,[14] and in fact, the information contained in those navigation guides is very limited. Due to various reasons such as being off the main shipping routes, being a dangerous ground for navigation, and complicated territorial disputes over islands and reefs, comprehensive hydrographic surveys have not been conducted. Almost all navigation guides and nautical charts currently used internationally acknowledge this fact.[15] The latest edition of the United States’ Sailing Directions(Pub. 161 South China Sea and the Gulf of Thailand) still emphasizes, “In the SE part of the South China Sea lies an oblong area about 52,000 square miles in extent, known as Dangerous Ground. Dangerous Ground is a large area to the NW of the Palawan Passage which is known to abound with dangers. No systematic surveys have been carried out in the area, and the existence of uncharted patches of coral and shoals is likely.”[16] Not only that, but also the United States’ Sailing Directions observes that "Due to the conflicting dates and accuracy of the various partial surveys of Dangerous Ground, certain shoals and reefs may appear on one chart, but not on Charted depths and their locations may present considerable error in the lesser known regions of this area. Avoidance of Dangerous Ground is the mariner's only assurance of safety."[17]

The arbitration tribunal, fully aware of the limitations of such evidence,[18] nonetheless used insufficient and inappropriate evidence to make hasty determinations. In fact, the tribunal didn't even compare the descriptions of the Second Thomas Shoal from all the navigation guides it had obtained, nor did it seriously distinguish the differences among them and analyze the underlying reasons.

Third, and even more unacceptable,  is that the interpretation of the two pieces of evidence contains obvious errors of logic. Paragraph 380 of the Award states that “the Tribunal notes in particular the description of rocks that ‘are almost certain to be visible at low water’ and takes this as an indication that no rocks on the reef would be visible at high water.” However, "visible at low tide" doesn't necessarily mean submerged at high tide. The only logical conclusion from this statement is that further observation at high tide is required to determine whether Second Thomas Shoal is above or below mean high tide.[19] This cannot rule out the possibility of Second Thomas Shoal being visible at high tide. There is clearly a fundamental logical flaw in this argument.

Fourth, the evidential material used in the ruling was incomplete. The document submitted by the Philippines, "China Sailing Directions: South China Sea (A103)" was incomplete. The description of Second Thomas Shoal contains only half of the intended text (up to page 179) and lacks a corresponding English translation. The award cited page 180 of the "China Sailing Directions", a page that was completely missing from the evidence submitted.[20]

Fifth, these two pieces of evidence have significant defects and are utterly insufficient for accurately determining the nature of Second Thomas Shoal. They are also in clear violation of the principle of "best available evidence,"  one thing, these pieces of evidence are not the best evidence to judge the nature of the feature from any perspective; for another, from the perspective of its availability, the Philippines was physically able to conduct a relevant hydrographic observation/survey, but the Philippines did not provide any information and data in this regard.

Article 9 of Annex VII to the UNCLOS provides that "[b]efore rendering its award, the arbitral tribunal must satisfy itself not only that it has jurisdiction over the dispute, but also that the claim is well founded in fact and in law". The standard of proof under "well founded in fact” , as interpreted by Judge Wolfrum  in the M/V Saga case,  is not merely a “preponderance of evidence” but a “proof beyond reasonable doubt.”[21] In a departure from his previously articulated standard, Judge Wolfrum appears to have contradicted his own established principle with the finding.

The above critical examination of the reasoning of arbitral ruling unveils the fragility of its finding regarding the Shoal's nature. The dependence on Philippines' selective and decontextualized claims, alongside antiquated evidentiary material, casts serious doubt on the finding's impartiality and accuracy. It is difficult to reconcile the characterization of Second Thomas Shoal as a low-tide elevation with the inherent limitations of relying on such demonstrably deficient and insufficient evidence.

“The role of the arbitrator or evaluator is to issue a determination or an evaluation based solely upon the objective facts and merits of the case.”[22] The finding, however, appears to deviate from this principle. Its flimsy construction, built upon a foundation of disregarded facts and weak arguments, fails to meet the expected threshold of judicial and professional quality. The absence of clear, compelling evidence and persuasive justification for the conclusions drawn raises questions about the impartiality and ethical considerations guiding the arbitral process.

Embracing the arbitral award like an infallible decree, the Philippines sails towards perilous waters, oblivious to the deceptive lure of the siren's song.[23]



"National Social Science Fund of China: Program No.22VHQ012"
[1] Statement of the DFA Spokesperson on the 10 November 2023 Ayungin Shoal Incident. Available at Statement of the DFA Spokesperson on the 09 December 2023 Bajo de Masinloc Incident and 10 December 2023 Ayungin Shoal Incident. Available at
[2] U.S. Support for our Philippine Allies in the Face of Repeated PRC Harassment in the South China Sea, PRESS STATEMENT,OFFICE OF THE SPOKESPERSON, OCTOBER 22, 2023. Available at
[3] The South China Sea Arbitration Award, Merits (Hereinafter referred to as Award of 12 July 2016), paras. 379-381. Available at
[4] There are relatively more discussions on the general issue of low tide elevation in the existing literature, but there is a lack of review of the individual features one by one. Bao Yinan's article "Evaluation of the Determination of the Natural Properties of Low Tide Elevation in the Award of the South China Sea Arbitration Case" has a brilliant discussion, but it does not focus on the issue of Second Thomas Shoal. See 包毅楠,《南海仲裁案实体裁决中低潮高地自然属性判定问题的评析》《当代法学》2017年第2期。Also see, Chinese Society of International Law. (2018). The South China Sea arbitration awards: A critical study. Chinese Journal of International Law, 17(2), 207-748. McDorman, T. L. (2017). An international law perspective on insular features (Islands) and low-tide elevations in the South China Sea. The International Journal of Marine and Coastal Law, 32(2), 298-315. Lavalle, R. (2014). The rights of states over low-tide elevations: A legal analysis. The International Journal of Marine and Coastal Law, 29(3), 457-479.
[5] Kazazi, Mojtaba. Burden of proof and related issues: a study on evidence before international tribunals. Vol. 1. Martinus Nijhoff Publishers, 1996. Also see, Liao, Shiping. "Fact-Finding in Non-Appearance before International Courts and Tribunals: A Review of the Tribunal's Practice in the South China Sea Arbitration." China Oceans L. Rev. (2022): 93.
[6] Sailing Direction for the Dangerous Ground, UKHO Ref. HD384, (1944 ed.) p. 6.
[7] Navigation Guarantee Department of the Chinese Navy Headquarters, China Sailing Directions: South 
China Sea (A103). Available at
[8] Second Thomas Shoal raises a number of questions of international law, including whether Second Thomas Shoal is a low-tide elevation. What is the legal nature of the low-tide elevation within the Spratly Islands claimed by China? Can the award disregard China's claim to the Spratly Islands as a whole and divide the status of individual features in the Spratly Islands? Can low tide features outside the territorial sea be claimed as territory? Do low-tide elevations beyond 12 nautical miles from high-tide features within 200 nautical miles of a country's baselines naturally become part of its EEZ and continental shelf? This article is limited to discussing whether Second Thomas Shoal is a low-tide feature.
[9] Chinese Society of International Law. (2018). The South China Sea arbitration awards: A critical study. Chinese Journal of International Law, 17(2), paras. 618-621.
[10] Territorial and Maritime Dispute (Nicaragua v. Colombia), Judgment, I.C.J. Reports 2012, p.624, at para.35.
[11] Award of 12 July 2016, para.338.
[12] Award of 12 July 2016, para.321.
[13] Territorial and Maritime Dispute (Nicaragua v. Colombia), Judgment, I.C.J. Reports 2012, p.624, at para.36.
[14] Award of 12 July 2016, para.379.[
[15] 中华人民共和国海事局,《中国沿海航行指南(南海海区)》(CNP6 ),人民交通出版社,2018年10月版。United States National Geospatial-Intelligence Agency, Pub. 161 Sailing Directions (Enroute), South China Sea and the Gulf of Thailand (17th ed., 2020). Japan Coast Guard, Document No. 204: South China Sea and Malacca Strait Pilot (Mar. 2011). United Kingdom Hydrographic Office, Admiralty Sailing Directions: China Sea Pilot (NP31), Vol. 2 (15th ed., 2021).
[16] Sailing Directions Pub. 161 South China Sea and the Gulf of Thailand, 17th Edition 2020, p.9, para.1.21. Available at
[17] Ibid., p.10, para.1.21.
[18] “The Tribunal considers it important that the absence of full information not be permitted to bar the conclusions that reasonably can be drawn on the basis of other evidence. At the same time, the limitations inherent in other forms of evidence must be acknowledged.” See, Award of 12 July 2016, para.321.
[19] For the selection of high tide datum, the Philippines adopts the Mean High Water (MHW) as its high tide datum, while China adopts the 1985 National Vertical Datum. 参见包毅楠,《南海仲裁案实体裁决中低潮高地自然属性判定问题的评析》《当代法学》2017年第2期,第143页。
[20] The South China Sea Arbitration, Memorial of Philippines, Volume VII, 30 March 2014, Annex 232. Available at
[21] 沃尔夫鲁姆法官认为, “确有事实和法律依据 "不是 "优势证据 "意义上的证据标准,而是与许多国家国内法制度中适用的 "排除合理怀疑 "意义上的证据标准相当。The M/V "Saiga" (No. 2) Case (Saint Vincent and the Grenadines v. Guinea), Separate Opinion of Vice-President Wolfrum, ITLOS Reports 2013, p. 94-95, para.12. Available at
[22] Rozas, J. C. F. (2010). Clearer ethics guidelines and comparative standards for arbitrators. Liber amicorum bernardo cremades, 413-449. Also see, Code of Conduct for Arbitrators in International Investment Dispute Resolution and Code of Conduct for Judges in International Investment Dispute Resolution with respective commentary of the United Nations Commission on International Trade Law resolution/adopted by the UN General Assembly. Available at
[23] Zheng, Zhihua, Beacon of Hope or Song of Sirens: Revisiting  the nature of South China Sea arbitration ruling (July, 2023). South China Sea Strategic Situation Probing Initiative (SCSPI) 
Available at

Zheng Zhihua

Dr. ZHENG Zhihua is an associate Professor of Japan Research Center of Shanghai Jiaotong University, and Head of East Asia Marine Policy Project. He is also a member of the Professional Committee of Maritime History and Culture Research of the China Maritime Society. He severed as the director of Joint Institute for Maritime Law and History, assistant dean of the School of International Shipping Law at East China University of Political Science and Law (ECUPL), and deputy secretary general of Shanghai Law and Society Association. He joined the board of editorial of China Ocean Law Review and severed as senior editor from 2010 to 2013. He was appointed as Judge of Ningbo Maritime Court in 2004. He got qualification for admission to the Chinese Bar in 1998. He was a visiting fellow of St. John’s College at Oxford University, Institute of Maritime Law at Southampton University and Law Faculty at Göettingen University.