Nine-Dash Line

Also known as: Nine-dashed line · Nine-dotted line · U-shaped line · Eleven-dash line (the 1947 ROC version still used by Taiwan) · Ten-dash line (PRC maps since 1984, adding a dash east of Taiwan) · Nánhǎi Duànxùxiàn / 南海断续线 (Chinese, "South Sea intermittent line") · Duànxùxiàn / 断续线 (Chinese, "intermittent line")

Government

Definition

Nine-Dash Line (Chinese: Nánhǎi Duànxùxiàn, “South Sea intermittent line”) is the name given to a set of nine line segments printed on Chinese maps that visually demarcate the maritime claims of the People’s Republic of China (PRC) — and, in an eleven-segment version, the Republic of China (ROC, Taiwan) — over most of the South China Sea. The line encloses or touches the Paracel Islands, the Spratly Islands, Pratas Island, Macclesfield Bank, Vereker Banks, and Scarborough Shoal, and swings to within roughly 200 nautical miles of the coasts of the Philippines, Malaysia, Vietnam, and Brunei, overlapping their United Nations Convention on the Law of the Sea (UNCLOS) entitlements. China has published no full set of coordinates for the dashes and has not clarified whether the line is a claim to the islands within it, to the waters, to historic rights over resources, or some combination of these; analysts, including a U.S. Department of State study, have grouped the possible readings into three such interpretations. (Wikipedia — Nine-dash line)

The line descends from an eleven-dash map issued by the ROC Ministry of Interior on 1 December 1947, the “Location Map of South Sea Islands” (Nánhǎi Zhūdǎo Wèizhì Tú), itself traced by scholars to a 1935 ROC map titled “Map of Chinese Islands in the South China Sea.” The PRC adopted a nine-dash version beginning in 1952, dropping two dashes in the Gulf of Tonkin in a gesture read as a concession to North Vietnam, and Chinese maps since 1984 have added a tenth dash east of Taiwan. In the arbitration instituted by the Philippines under Annex VII of UNCLOS, the tribunal held in its 12 July 2016 award that “there is no legal basis for any Chinese historic rights, or sovereign rights and jurisdiction beyond those provided for in the Convention, in the waters of the South China Sea encompassed by the ‘nine-dash line’.” China rejected the award and continues to publish the line, most prominently in its 2023 “standard map,” which drew protests from the Philippines, Vietnam, Malaysia, Taiwan, and Japan. (Wikipedia — Nine-dash line, 2016 Annex VII Award (RIAA))

Identities

Source Type	Identity
Wikipedia	Nine-dash line
Wikidata	Nine-dash line (Q2735499)
DBpedia	Nine-dash_line
ProductOntology	N/A
Wiktionary	nine-dash line
Library of Congress Subject Headings (LCSH)	South China Sea
MeSH	N/A
NCBI Taxonomy	N/A
AGROVOC	N/A
Google Scholar	nine-dash line South China Sea historic rights UNCLOS arbitration 2016 award
ConceptNet	N/A
OpenCyc	N/A

Also Known As

Nine-dashed line
Nine-dotted line
U-shaped line
Eleven-dash line (the 1947 ROC version still used by Taiwan)
Ten-dash line (PRC maps since 1984, adding a dash east of Taiwan)
Nánhǎi Duànxùxiàn / 南海断续线 (Chinese, “South Sea intermittent line”)
Duànxùxiàn / 断续线 (Chinese, “intermittent line”)

Examples and Analogies

A boundary without coordinates: The dashes appear on maps like a fence line, but China has never filed the precise coordinates that would let other states know exactly what is enclosed, leaving neighbors to guess whether islands, waters, or only fisheries are claimed. (Wikipedia — Nine-dash line)
A map older than the treaty: The 1947 eleven-dash map predates UNCLOS by decades, and the 2016 tribunal treated that history as legally inert — accession to the Convention, it held, superseded any historic rights to resources that exceeded the maritime zones UNCLOS permits. (2016 Annex VII Award (RIAA))
Dashes as negotiation history: The two dashes removed from the Gulf of Tonkin in 1952 are often cited to show that the line has been edited for diplomatic reasons, as the removal is read as a concession to North Vietnam at the time. (Wikipedia — Nine-dash line)
The 2009 note verbale as unveiling: China attached a nine-dash map to notes verbales lodged with the UN Secretary-General in May 2009 to protest Malaysian and Vietnamese continental-shelf submissions, converting a decades-old cartographic device into a live diplomatic claim that neighbors formally protested in turn. (Wikipedia — Nine-dash line)

Usage Scenarios

1. Diplomatic Protests and Note Verbales

States bordering the South China Sea cite the line — and the 2016 award addressing it — in protests and UN communications, as when Malaysia, Vietnam, Indonesia, and the Philippines objected to China’s 2009 submission and its successors, and when claimants protested the 2023 standard map. (Wikipedia — Nine-dash line)

2. Legal Argumentation Under UNCLOS

Lawyers and tribunals treat the line as the object of the 2016 award’s ruling on historic rights, a ruling examined in the Philippines v. China and United Nations Convention on the Law of the Sea entries on this site; the award found the claim of historic rights to resources within the line incompatible with the Convention. (2016 Annex VII Award (RIAA), Wikipedia — South China Sea Arbitration)

3. Cartography and Mapping Disputes

Publishers, airlines, and governments confront decisions about whether to print the line on maps of Asia, since including it is read as endorsing the Chinese position and omitting it draws Chinese objections, as the 2023 standard map controversy illustrated. (Wikipedia — Nine-dash line)

4. Journalism and Policy Analysis

Reporters and analysts use the line as shorthand for the full Chinese claim when covering incidents at Scarborough Shoal, Second Thomas Shoal, and the Spratlys, distinguishing the cartographic claim from the particular conduct in dispute. (Wikipedia — South China Sea Arbitration, Wikipedia — Spratly Islands)

Strategies

Analyze the line’s legal character by separating its three possible meanings — claim to islands, claim to waters, or claim to historic rights over resources — since the 2016 award negated only the third as between the Philippines and China. (2016 Annex VII Award (RIAA))
Anchor counter-claims in UNCLOS zones measured from coasts and from qualifying land features, the framework the tribunal applied when it found no basis for historic rights beyond Convention limits. (2016 Annex VII Award (RIAA))
Document the line’s variations — eleven, ten, or nine dashes — when assessing the scope of the claim at any given moment, since the number and placement of dashes have changed over time. (Wikipedia — Nine-dash line)
Track collective and individual state responses to the 2016 award, given that as of late 2023 a group of governments had called for the ruling to be respected while China and seven others rejected it. (Wikipedia — South China Sea Arbitration)
Note China’s own clarifications, such as Foreign Minister Wang Yi’s 2020 statement that China does not claim all waters inside the line as internal waters or territorial sea, which preserves ambiguity about what the line does claim. (Wikipedia — Nine-dash line)

Security and Safety Measures

Treat incidents near the line’s edge — at Scarborough Shoal, Second Thomas Shoal, and Reed Bank — as flashpoints where law-enforcement and naval vessels operate in close proximity, and apply de-escalation and reporting procedures. (Wikipedia — South China Sea Arbitration)
Verify the provenance and date of any map bearing the line before using it in official or public communication, because versions differ and each carries diplomatic signaling. (Wikipedia — Nine-dash line)
For vessels and aircraft transiting waters within the line, file flight and voyage plans, maintain communications, and preserve records, since jurisdictional assertions in the area are contested. (Wikipedia — Spratly Islands)
Preserve evidence and diplomatic paper trails when conduct within the line is challenged, following the practice of states that have lodged protests and taken disputes to compulsory procedures under UNCLOS. (2016 Annex VII Award (RIAA))

Historical Context

The line’s origin lies in Republican China’s wartime and postwar cartography. A 1947 ROC “Location Map of South Sea Islands” published on 1 December 1947 drew eleven dashes around the South China Sea, and scholarly accounts place its issuance between 1946 and 1948 and connect it to a 1935 map of the ROC Land and Water Maps Inspection Committee. After 1949 the retr ROC kept the eleven-dash version, while the PRC from 1952 printed nine dashes after removing the two in the Gulf of Tonkin, a change interpreted as accommodation of North Vietnam; the PRC-Vietnam boundary in the gulf was formalized by treaty in 2000. (Wikipedia — Nine-dash line)

The line remained largely dormant in international law until 7 May 2009, when China attached a nine-dash map to notes verbales protesting Malaysia’s and Vietnam’s submissions to the Commission on the Limits of the Continental Shelf, provoking counter-protests by those states, by Indonesia, and by the Philippines. The Philippines then instituted arbitration under Annex VII of UNCLOS in January 2013. On 12 July 2016 the tribunal ruled for the Philippines on most submissions, holding that China’s claim to historic rights to resources within the line was incompatible with the Convention and that “there is no legal basis” for such rights beyond what UNCLOS provides, while expressly declining to rule on sovereignty over land territory or to delimit boundaries. China rejected the award and did not participate; Taiwan also rejected it. As of November 2023, roughly two dozen governments had called for the ruling to be respected, while eight, including China and Taiwan, had rejected it. (Wikipedia — Nine-dash line, Wikipedia — South China Sea Arbitration, 2016 Annex VII Award (RIAA))

Challenges and Controversies

Legal Status of the Line

The core controversy is whether the line has any legal effect as a maritime claim. The 2016 tribunal, deciding the question as between the Philippines and China, found historic rights to resources within the line incompatible with UNCLOS and without legal basis; China maintains that the award is null and void and that its historic rights predate and survive the Convention. (2016 Annex VII Award (RIAA), Wikipedia — South China Sea Arbitration)

Deliberate Ambiguity

China has never published coordinates for the dashes or stated definitively what the line encloses; scholars and the U.S. State Department identify competing readings (islands only, waters, or historic rights), and Foreign Minister Wang Yi stated in 2020 that China does not claim all waters within the line as internal waters or territorial sea. Neighbors argue the ambiguity itself destabilizes the region. (Wikipedia — Nine-dash line)

Overlap With Coastal States’ Entitlements

The line’s outer dashes cut through the exclusive economic zones and continental shelves that the Philippines, Vietnam, Malaysia, and Brunei would derive from their coasts under UNCLOS, generating the standing frictions over fisheries, oil and gas exploration, and law enforcement that define the South China Sea disputes covered in the South China Sea entry on this site. (Wikipedia — Spratly Islands)

Maps as Signals

Periodic Chinese map publications — the vertical maps of 2013-2014 with a tenth dash near Taiwan, and the 2023 standard map — have repeatedly triggered protests from the Philippines, Vietnam, Malaysia, Taiwan, and Japan, illustrating how the line functions as a continuing assertion of claim rather than a settled boundary. (Wikipedia — Nine-dash line)