TOKYO -- In a move aimed at preventing accidental military clashes, Japan and China have agreed to implement a bilateral communication mechanism starting on June 8.

The agreement, which ends 11 years of negotiations to establish the Maritime and Aerial Communication Mechanism, was the highlight of a meeting in Tokyo between Japanese Prime Minister Shinzo Abe and Chinese Premier Li Keqiang on Wednesday.

"We will make the East China Sea into a sea of peace, cooperation and friendship by easing tensions and fostering mutual trust," Abe said at a press conference after attending Wednesday's signing ceremony. "Representatives of the two countries' defense authorities have just signed a memorandum."

Li echoed and said "the clearing-up weather heralds a favorable future for China and Japan."

The mechanism features three pillars: a dedicated radio frequency and language for communication between the Japanese Self-Defense Forces and Chinese military; a hotline connecting the two countries' senior defense officials; and regular discussions between the officials to build trust.

The first pillar is key to avoiding unintended clashes, but the countries will also "use conventional means of communication involving military ships and airplanes," according to a document released by the Japanese Defense Ministry.

In other words, frontline communication remains mostly unchanged even after the mechanism goes into effect.

The two countries began discussing the mechanism in 2007. In the interim, however, the geopolitical landscape changed greatly, according to people familiar with the issue. Specifically, Japan, the U.S., China and 18 other countries concluded the Code for Unplanned Encounters at Sea in 2014 to reduce the chance of maritime accidents between nations in the accord. Hence, the importance of a bilateral mechanism between Japan and China diminished somewhat since 2007.

Still, the mechanism adds a new dimension as it calls for regular dialogue between senior defense officials, an area not covered by CUES.

But the agreement will hardly change Japan's frontline readiness to cope with China's military activities. "It is questionable if [the accord] can reduce the risk of clashes," a defense official said.

The Japanese Self-Defense Forces deeply distrust China's military owing to its "persistent refusal to abide by basic rules at sea," an official stated. The new mechanism will not be effective in reducing the chance of clashes unless it is properly implemented, the official said.

Japan and China had agreed on the basics of the mechanism by 2012. But negotiations dragged on due to Tokyo's decision to put the Senkaku Islands in the East China Sea under state control in 2012, arousing the ire of Beijing, which claims sovereignty over the uninhabited islets, calling them the Diaoyu Islands.

The two governments haggled over whether the mechanism should apply to waters and airspace around the Senkakus. Japan insisted that it should not, fearing that Chinese vessels would use the mechanism as a pretext to enter Japanese territorial waters near the islets. China demanded that the mechanism should not be limited, especially as regards the Senkakus owing to the high risk of clashes there.

The two countries failed to settle differences for six years before eventually agreeing to Beijing's insistence on no geographical limits.

"Abuse of the mechanism can be prevented by deepening trust," a senior official at the Japanese Foreign Ministry said. But it is unclear whether the settlement can prevent abuses.

While the hotline will be set up "at the earliest possible date," it is unclear who will be manning the lines of communication. Counterparts will be chosen "on a case-by-case basis," the Japanese Defense Ministry said. Both sides, however, are still ill-prepared.

Chinese President Xi Jinping moved to improve Sino-Japanese relations in June 2017. Since then, Beijing has been making forward-looking proposals regarding the communication mechanism. In addition, the frequency of Chinese government vessels entering Japanese waters around the Senkakus has dropped to twice a month from thrice monthly since last August.

While still at odds with Japan over historical issues and the Abe administration's tilt towards Taiwan, China wants to avoid further tensions over the Senkakus and generally improve relations with its neighbors -- a position calculated to counter the aggressive stance of U.S. President Donald Trump towards Beijing.

But some in Japan remain unconvinced by China, with a senior Japanese Defense Ministry official saying, "It is unclear how effectively the Chinese military is disciplined."

This leaves it up to frontline defense personnel with their already established means of communication to prevent accidental military clashes, even with Sino-Japanese relations now on relatively stable footing.