What I found about the Cairo Declaration:

> The Cairo Declaration stated that “all the territories Japan has stolen from the Chinese, including Manchuria, Formosa, shall be restored to the Republic of China.” The Spratlys and the Paracels were not seized or stolen by Japan from China. Japan seized the Paracels from the French and the Spratlys were unoccupied by any state when Japan established a submarine base in Itu Aba in 1939. In fact, in the 1943 China Handbook, an official publication of the Republic of China delineating China’s territory, China did not claim the Spratlys. The Cairo Declaration stated that “Japan will also be expelled from all other territories which she has taken by violence and greed.” The Spratlys and the Paracels fall under these “all other territories,” which were not awarded to any state in the Cairo Declaration.

What I found about the San Francisco Treaty:

> China, under the People’s Republic of China ruled by the Communists, denounced the 1951 San Francisco Peace Teary as illegal since China was not represented at the Peace Conference. The USSR’s motion to award the Spratlys and the Paracels to China was overwhelmingly rejected by the Peace Conference by a vote of 64 to 3, with one abstention.

>The Japanese accepted the terms of surrender set by the Potsdam Declaration, including the terms of the 1943 Cairo Declaration, which provided that Japan would return all Chinese territories that it had seized from China. Since Nansha and Xisha were occupied by Japan during World War II, they were returned to China. Thus, both the 1951 San Francisco Japan Peace Treaty and the 1952 Sino-Japan Treaty stipulated that Japan renounce all title and claim to Taiwan (Formosa), Penghu (Pescadores), the Parcel Islands and the Spratly Islands. Since then, Japan has not expressed any new position on China's claim of sovereignty over the islands in the South China Sea.

Claimants who recognize Chinese claims: Indonesia, North vietnam

Claimants who didn't: South Vietnam, Malaysia, PHILIPPINES

Philippines emphasized since what you found/quoted is basically the Philippine legal position from by their chief justice, Antonio Carpio from last month. Obviously every country have their own biases, arguments for nullifying others claims and again they are _legitimate_ arguments. But the more detached analysis and literature, like this analysis from the 90s before everything popped off, gives greater credence Chinese position. Just to pick on Philippines claims on Scarborough Shoal, based off terra nullius, from the mid 50s, i.e. Filipino claims to be first state/peoples to occupy the shoal, which is... well fantastically absurd since ROC claimed the shoals in early 1900s, which predates Philippines as a sovereign state. They're so late to the party that their argument is... China (and Vietnamese) claims that predates even San Francisco treaty just don't exist. Although this line is interesting, I can't find info on it anywhere.

> USSR’s motion to award the Spratlys and the Paracels to China was overwhelmingly rejected by the Peace Conference by a vote of 64 to 3

From context, speculating USSR probably wanted to award it to PRC... which doesn't invalidate the notion that ROC claims were recognized, as reflected by international reactions at the time, by who would eventually represent China, which later passed to PRC after in 71. Anyway, the Filipino position is stupid, legitimate, but stupid. Just like some of the new Chinese straight baseline arguments in response to PCA ruling. Look it up. Insert Arrested Development meme on the absurdity of maritime law. At the end of the day, it doesn't matter, each party is motivated to find minutiae to argue their case, geopolitical interests will shift positions (lol at US neutrality). Ultimately, IR is more rule by law than rule of law. Everyone has legal arguments, some older and better than others. Everyone also has a navy, some bigger and more modern than others. SCS dispute is going to be solved by 9/10th possessions and naval tonnage. There's too much on the line for any other way.

Edit, to add, since I just connected Carpio dot to point about Sino-Philippine energy exploration I made in another comment: In Philippines case, Carpios letter was followed up by Philippine declaring they would start oil exploration in SCS. The timeline suggesting Philippines asserting itself... but later revealed to be with Chinese blessing [1]. That's SCS dispute politics.

[0] https://scholarlycommons.law.case.edu/cgi/viewcontent.cgi?ar...

[1] https://amti.csis.org/a-philippine-china-deal-on-joint-devel...

What I gather they say is Japan gives up rights to the SCS and territories they siezed from China are returned to China (RPC, ROC, whatever).

However it doesn't say the Spratlys and the Paracels are returned to China, for example because Japan seized them from China.

I agree with your last points - the larger picture is that China can claim whatever they want, but their arguments aren't good enough to get the approval of major world players. So they'll have to protect their position with force or trading favors.

Which is inevitable, even in the 60s when significant countries were fine with Chinese claims, these legalities barely mattered to resolving the disputes since no interested party had the power to enforce anything. There's so much resources and security tied to maritime control in this region that this is only a dispute that can be solved through force. Along the same lines, it doesn't matter what regional or major world players think about Chinese legal arguments if China can enforce it via tonnage. Right now the only viable opposition is USN + FONAPS. But that's kind of status quo US+China is comfortable with, everyone dick waves without touching tips.

The important point in terms of "claims" is where previously plurality parties endorsed Chinese legal nitpicks (hence China has the earliest and strongest claims), now they do not, not because other claimants have better arguments, but because geopolitical interests changed. The quality of the arguments do not matter, nor the laws if we're honest. China explicitly did not submit to UNCLOS arbitration mechanism, so the PCA ruling hack was not to decide on sovereignty but maritime boundary but defining what is / is not features to deprive China (and other countries) of EEZ and territoriality. Right now China "adheres" by limiting weaponization, and drafting other legal arguments to legitimize holdings for more territorial perks. But that's just a stalling tactic until Chinese Navy is large enough to control the region defacto.

This is what I don't agree with. It seems you were referring to those treaties to show that the world accepted China's argument. But I don't see the evidence of that; at most they were just non-committal.

Of course it matters how good their argument is – if it was stronger than enough countries would be interested in maintaining stable international order to back them up.

>Of course it matters how good their argument is – if it was stronger than enough countries would be interested in maintaining stable international order to back them up.

No international actor wants a regional Asian hegemony except China, there's no argument strong enough to override such interests. And there's no argument strong enough to form consensus among 6 claimants or US desire for Chinese containment. SCS is simply not a dispute that can be solved legally / multilaterally anymore, unless bilaterally under Chinese terms like original UNCLOS accession conditions. In the meantime, China has the industrial capacity change the conditions on the ground. Probably the most expedient method now, hence arguing over claims is not productive. The claims exist with clear historical documentation, for pretense of Chinese enforcement, that's all that matters.