Are maps relevant in territorial disputes over ownership of tiny islands in the South China Sea? The question arises because maps are usually drawn unilaterally by one state. This raises the issue of whether such maps showing islands as part of the territory of the state drawing the map can bind another state which also claims the same islands as its territory. In the South China Sea dispute, all the claimant states have unilaterally drawn maps showing that the South China Sea islands belong to them.
The rule in international law is that a map drawn by one state can only bind other states if the map is made an integral part of a treaty between or among states. The states that are parties to the treaty are deemed to have accepted the map. There is, however, an important exception to this rule. A map can bind a state, even if it is not made an integral part of a treaty, if the state has unilaterally accepted the map. This exception applies to a map unilaterally drawn by a state, which makes such map binding on the state drawing the map. Thus, if a state unilaterally draws a map showing that an island does not belong to it, or showing that an island belongs to another state, then the state drawing the map is bound by such map. In law, this is called an admission against interest.
In the territorial dispute between Malaysia and Singapore over the tiny Pedra Branca rock in the Straits of Singapore, Singapore presented as evidence six maps unilaterally drawn and published by Malaysia in the 1960s and 1970s showing that Pedra Branca belonged to Singapore. In its 2008 Judgment, the International Court of Justice (ICJ) stated, “The Court concludes that those maps tend to confirm that Malaysia considered that Pedra Branca/Pulau Batu Puteh fell under the sovereignty of Singapore.” The ICJ quoted with approval the decision in the 2002 case between Eritrea and Ethiopia, which stated: “The map still stands as a statement of geographical fact, especially when the State adversely affected has itself produced and disseminated it, even against its own interest.”
Thus, while a map unilaterally drawn by one state cannot bind another state, the same map can bind the state drawing the map since such map may constitute an admission against interest. This is where the ancient maps of China, from the Tang dynasty to the Qing dynasty, spanning almost a millennium, play an important role in the territorial dispute over the South China Sea islands. All these ancient maps of China were officially published by the People’s Republic of China in a three-volume atlas titled “An Atlas of Ancient Maps of China,” released in 1990, 1994, and 1997.
All the ancient maps of the Chinese dynasties show that Hainan Island was the southernmost territory of China. Chinese territory never reached the Paracel Islands, the Spratly Islands, or Scarborough Shoal. China is bound by these ancient maps which were officially published as authentic by the People’s Republic of China. All these maps are admissions by China that China never owned or occupied the South China islands throughout the Chinese dynasties.
These ancient maps published and disseminated by the People’s Republic of China debunk China’s own claim and historical narrative that the South China Sea islands were already Chinese territories since 2,000 years ago. China now understands that these ancient maps will devastate its claim if these maps are presented by other claimant states before an international tribunal.
This is one reason why China has refused to submit the territorial disputes over the South China Sea islands to voluntary arbitration by the ICJ or by an international tribunal. There is no treaty or convention compelling China to submit these territorial disputes to compulsory arbitration. Unless China agrees to a voluntary arbitration, no international tribunal can acquire jurisdiction over these territorial disputes involving China.
The Chinese government now prohibits any Chinese citizen from publishing maps of China to avoid any deviation from its historical narrative. But it is too late. China’s historical narrative has already been debunked by its own official publication — “An Atlas of Ancient Maps of China” — which constitutes a binding admission against China’s own interest.