By Hiroyuki Akita, senior staff writer

TOKYO — Chinese Premier Li Keqiang looked a bit stiff and awkward when he last week met with Japanese national security chief Shotaro Yachi, a special envoy sent to Beijing by Japanese Prime Minister Shinzo Abe.

That was actually not surprising. When he met with Abe in Mongolia on July 15, Li voiced an unusual warning about Japan’s actions concerning territorial disputes in the East China Sea and the South China Sea.

Three days earlier, an international tribunal had rejected China’s claims to historic and economic rights in most of the South China Sea.

Abe told Li that China should accept and observe the ruling.

According to multiple informed sources, Li replied, “We cannot accept the ruling. If it is implemented, there will be conflict.”

Li also suggested that conflict could occur in the East China Sea, depending on how Japan and the U.S. respond.

Both Tokyo and Beijing have kept the Chinese premier’s remarks secret.

Chinese foreign policy experts, however, have downplayed the importance of Li’s words. He referred to “conflict,” not “war,” they noted, pointing out that there are already territorial disputes in the South China Sea.

Still, Li adopted unusually provocative rhetoric in conveying his message to Abe.

In early August, about three weeks after Abe’s meeting with Li, some 200 to 300 Chinese fishing boats suddenly appeared around the disputed Senkaku Islands in the East China Sea, the principal flash point between Japan and China.

Despite repeated protests from Tokyo, Chinese government vessels, which numbered up to more than a dozen, also appeared in Japanese waters around the islands.

Both Japan and the U.S. were caught off guard by China’s provocative acts.

That’s because many officials of both the Japanese and the U.S. governments believed China would avoid rocking the boat, at least until this year’s Group of 20 summit, in China on Sept. 4-5. China needs cooperation from other countries to ensure the success of the event.

But China did exactly what it was expected to avoid doing.

Two theories

Japanese government officials are now discussing two theories about why Beijing has deliberately created a disturbance in sensitive areas around the Senkaku Islands.

One theory is that Beijing is convinced the the administration of U.S. Barak Obama will never take strong action against China.

Beijing came to that view when Susan Rice, Obama’s national security adviser, visited China on July 25. During her meeting with President Xi Jinping, Rice reportedly did not clearly criticize China over the South China Sea issue.

After the meeting, Chinese diplomats conveyed the following message from Beijing to Southeast Asian nations: “The U.S. has stopped officially criticizing China over the South China Sea issue. You had better follow suit.”

This theory, however, ignores the fact that Rice has long been an advocate of a conciliatory policy toward China.

The other theory about Beijing’s unanticipated provocation is that Xi opted to provoke Japan to avoid being blasted for the tribunal ruling, which is seen as his major diplomatic blunder, during the annual summer closed-door meeting of party seniors at the beach resort of Beidaihe.

Xi ordered the massive and assertive mobilization of vessels in disputed areas in the East China Sea in order to protect his political skin, according to this theory.

Japan’s response to China’s behavior will depend on which of the two theories it believes.

If China is betting that Obama will do nothing to stop it, Japan should take a tough stance toward Beijing.

But if Xi is acting out of concerns about being criticized by party seniors, putting pressure on him could backfire.

The reality is, probably, a combination of the two factors. The question is which factor is more relevant.

China’s behavior at the upcoming G-20 summit will offer some insight into this question, which has huge implications for the world as a whole.