The Truth About the Nine-Dash Line: History, Disputes, and Why Neighbors Oppose It

Introduction

The Nine-Dash Line has become one of the most controversial boundaries in modern geopolitics. Covering up to 90% of the South China Sea, this line is at the heart of disputes between China and several Southeast Asian nations. But where did it come from, and why do so many countries reject it?

Origins of the Nine-Dash Line

The story begins in 1947, when the Republic of China (ROC) government published an official map showing an eleven-dash line around most of the South China Sea. This was shortly after World War II, when Japan surrendered islands it had occupied during the war. The ROC used historical Chinese records to justify including almost all of the South China Sea within its claim.

When the People’s Republic of China (PRC) took over in 1949, it adopted the same claim but removed two dashes in the Gulf of Tonkin to improve relations with North Vietnam resulting in the nine-dash line we know today.

Why Was It Introduced?

The nine-dash line was initially intended to:

Reassert sovereignty over islands Japan had occupied.

Secure potential resources, including oil, gas, and rich fishing grounds.

Establish strategic control over one of the busiest maritime routes in the world.

At the time, it wasn’t drawn with exact coordinates or clear definitions. This ambiguity has fueled disputes ever since.

Why Neighboring Countries Reject It

Almost all modern neighbors the Philippines, Vietnam, Malaysia, Brunei, and Indonesia oppose the nine-dash line because it overlaps with their exclusive economic zones (EEZs) under the United Nations Convention on the Law of the Sea (UNCLOS).

Key reasons for rejection:

1. Violation of EEZ Rights

UNCLOS grants coastal nations rights over resources within 200 nautical miles from their shores. The nine-dash line cuts deeply into these zones.

2. International Ruling Against It

In 2016, the Permanent Court of Arbitration (PCA) ruled that the nine-dash line had no legal basis and was incompatible with UNCLOS. China rejected the decision.

3. Maritime Tensions and Clashes

The Chinese coast guard and maritime militia frequently patrol disputed waters, often leading to standoffs, blockades, and collisions with other nations’ vessels.

4. Seen as Expansionism

Many Southeast Asian countries view the nine-dash line as a way for China to expand its influence and control strategic waterways.

The South China Sea Today

The South China Sea remains a flashpoint in Asia. With rich natural resources and vital trade routes at stake, the disputes show no sign of ending soon. For smaller nations, the fight is not only about fishing rights or oil reserves it’s about protecting national sovereignty.

Conclusion

The nine-dash line’s origins may be rooted in post-war history, but its implications are very much part of today’s geopolitical reality. As tensions continue, understanding its history and why neighbors reject it is key to seeing the bigger picture in the South China Sea disputes.