People's Daily yesterday published a call for a review of Japan's sovereignty over the island of Okinawa, home to major US bases, with the Asian powers already embroiled in a territorial row.
The article in the Communist Party mouthpiece argued China may have rights to the Ryukyu chain, which includes Okinawa.
Agreements between allied forces during the second world war mean the ownership of the Ryukyu Islands may be in question, the researchers argued in a commentary.
Asked if China considered Okinawa part of Japan, Foreign Ministry spokeswoman Hua Chunying said scholars had long studied the history of the Ryukyus and Okinawa.
"It may be time to revisit the unresolved historical issue of the Ryukyu Islands," wrote Zhang Haipeng and Li Guoqiang , of the Chinese Academy of Social Sciences.
Okinawa is home to major US air force and marine bases as well as 1.3 million people, nearly all of whom are Japanese nationals and speak Japanese.
The authors of the article said the Ryukyus were a "vassal state" of China before Japan annexed the islands in the late 1800s.
"Unresolved problems relating to the Ryukyu Islands have reached the time for reconsideration," they wrote, citing post-war declarations that required Japan to return Chinese territory.
In Tokyo, Chief Cabinet Secretary Yoshihide Suga dismissed the article as "injudicious".
"They are unmistakably part of our country's territory. That is a fact accepted historically and by the international community," he said.
Questions over Japan's right to Okinawa were probably aimed at raising the stakes in the East China Sea dispute, said Willy Lam, an expert on Chinese politics at Chinese University.
"I think this is psychological warfare," he said.
"The major point is to put pressure on Japan so that the Japanese administration will be forced to make concessions over the Senkaku [or Diaoyu] Islands."
Okinawa is the biggest of the Ryukyu Islands, which stretch for about 1,000 kilometres from Japan's mainland and were the centre of the Ryukyuan kingdom that paid tribute to Chinese emperors until it was absorbed by Japan in 1879. Some Chinese see the historical ties as a basis for sovereignty and dismiss Japan's possession of the islands as a legacy of its aggressive expansionism that ended in defeat at the end of the war.
Beijing has not made such claims, but state media occasionally questions Japan's authority.
Agence France-Presse, Bloomberg
A history of the Ryukyu Islands
589-617: Sui dynasty - first reference in Chinese annals to Ryukyus
7th century: First reference in Japanese to "Southern Islands"
14th century: Three Kingdoms established on Okinawa
1372: Chuzan Kingdom begins paying tribute to China
Late 14th century: many Chinese move to Ryukyus to pursue business. China recognises rule of Chuzan Kingdom.
1429: Okinawa united under the Sho (Shang in Chinese) dynasty
1609: Feudal lords from Kagoshima, Japan, conquer Ryukyus, before restoring degree of autonomy; kingdom also begins paying tribute to Japan
1655: Japan's Tokugawa shogunate approves tribute relations between Ryukyus and Qing dynasty court
1872: Following Meiji restoration, Japan abolishes kingdom
1879: Japan annexes Ryukyus as Okinawa prefecture
1880: China rejects proposal to divide islands between nations
1895: China abandons claim to islands under treaty ending Sino-Japanese war
1945: US military keeps control of Okinawa after end of war
1972: US returns islands to Japan
Sources: Wikipedia, Chan Yang-kit, SCMP archive