Gavan McCormack, emeritus professor at Australian National University, called any claim "quite unrealistic", adding it was probably "an extreme position to try and attract Japan back to the negotiating table".
Jia Qingguo, an international relations expert at Peking University, added: "I don't think the Chinese government wants to further complicate the already complicated issue."
Still, questions being raised over Japan's sovereignty worry Akihiro Kinjo, a 25-year-old Okinawa native and restaurant manager in Beijing.
Okinawa was the site of a deadly 1945 battle between Japan and the United States.
"Our grandmothers experienced war and based on their stories they had a horrible time," he said.
Under a security treaty with Japan the US maintains major military facilities on the island, and Washington is also making a strategic "pivot" to Asia, raising fears in Beijing of containment.
In August, the World Journal, a military affairs tabloid, carried a cover showing a projectile soaring toward Okinawa under the headline: "People's Liberation Army guided missile targets Okinawa bases."