ON MAY 8, the People's Daily of China ran a 4,000-word commentary entitled "On the Shimonoseki Treaty and its implication for the Diaoyu islands".
The article detailed the historical process whereby Japan seized control of the Ryukyu island chain, which includes Okinawa, from China and also the Diaoyu islands, which the Japanese refer to as Senkaku.
At the end of the commentary, its two authors noted that after the signing of the Shimonoseki Treaty in 1895, which ended the first Sino-Japanese War, the Qing Dynasty was too weak to raise the issue of the Ryukyus, Taiwan and its adjacent islands, including the Diaoyu islands. In this way, the islands came under Japan's control.
In 1941, when China formally declared war on Japan, it also abrogated all treaties and agreements, including the Shimonoseki Treaty. When World War II ended in 1945 with the surrender of Japan, the subsequent Cairo Declaration and Potsdam Declaration stipulated the post-war handling of Japan, which was accepted by Japan's Emperor.
In accordance with the stipulations, not only should Taiwan and Penghu be returned to China, but "the unresolved historical issue of the Ryukyu islands should be reconsidered", wrote the authors, Mr Zhang Haipeng and Mr Li Guoqiang of the Chinese Academy of Social Sciences.
It was the first time in nearly 70 years that China has raised the sovereignty of the Ryukyu chain, a move that shocked both Japan and the United States.
It prompted Japanese Prime Minister Shinzo Abe to say that Tokyo "must voice its position to the world" by rejecting Beijing's claim. The US State Department said Washington recognises Japan's sovereignty over Okinawa but "does not take a position on the underlying question of the ultimate sovereignty of the Senkaku islands".
Mr Li said the purpose of the commentary was not to claim back the Ryukyus, but "to restore the original face of history".
In an interview with the Global Times, he said: "It is not our intention to talk about 'China's claim' over the Ryukyus as they belonged to neither China nor Japan. But Japan's repeated provocation over the Diaoyu islands made it necessary for us to clarify these historical points."
Japan tried to claim sovereignty over the Diaoyu islands on the basis that they were part of the Ryukyus, according to Mr Li.
"Yet all the official historical records of the (former) Ryukyu Kingdom prior to its annexation by Japan did not include Diaoyu as part of its territories," he said.
Therefore, to counter Japan's claim over the Diaoyu islands, China has to raise the issue of the Ryukyus' sovereignty, he explained.
Since Mr Abe became premier last December, he has gone on a drive to revise the country's pacifist Constitution as part of plans to beef up the military. For the first time, Japan marked Restoration of Sovereignty Day on April 28, the same day in 1952 that the San Francisco Peace Treaty took effect, officially ending World War II and the Allied occupation of Japan.
Before he took office, Mr Abe had suggested revising a 1995 statement by then Prime Minister Tomiichi Murayama who publicly apologised for Japanese atrocities during World War II. But his government has since said there are no plans to do so.
China's sovereignty over the Ryukyus is well-documented in records. When the US-led Allied powers held discussions on "restoring territories", referring to Chinese territories that Japan had taken by force, both the Ryukyus and Taiwan were included.
According to US records (Roosevelt-Chiang Dinner Meeting, Foreign Relations of the United States, 1943), Generalissimo Chiang Kai-shek said in reply to a question from then US President Franklin D. Roosevelt that "China would be agreeable to joint occupation of the Ryukyus by China and the US and, eventually, joint administration by the two countries under the trusteeship of an international organisation".
But the defeat of Generalissimo Chiang's Kuomintang (KMT) by the Chinese Communist Party in 1949 after a civil war led the US to change its mind. In a bid to contain communism, the US set up an island chain of defence, with the Ryukyus becoming a pivotal link. The US handed control of the Ryukyus (Okinawa) to Japan at the 1951 San Francisco Peace Conference. Neither China nor Taiwan was invited to take part.
Both the KMT government in Taipei and the communist government in Beijing protested against this unilateral decision by the US and declared that they would not recognise the arrangement stipulated in the peace treaty with Japan and neither would they be bound by it.
This is the legal basis for China to say that it is time to revisit the Ryukyus sovereignty issue.
By proposing to reopen discussions on the Ryukyus' sovereignty, China is reminding Japan not to push the envelope.