Foreign Minister Wang Yi's trip to Tokyo, starting on Tuesday, is expected to set the tone for cooperation between China, Japan and the Republic of Korea ahead the G20 summit to be held in Hangzhou early next month, a source close to the issue said.

Foreign ministers of the three countries will meet in Tokyo on Wednesday morning under the regular trilateral mechanism which was resumed in March last year after a three-year hiatus.

"As the three major engines for the Asian economy, cooperation between China, Japan and the ROK is vital for East Asian economic cooperation," the source, who declined to be identified, said.

With their combined economies accounting for one fifth of the global total and 70 percent of the Asian economy, the three countries started the 10th round of negotiations on a free trade zone.

However, lack of political trust has cast shadows on economic and trade cooperation among the three powers.

Tokyo's illegal claim on the China-owned Diaoyu Islands in the East China Sea, its interference in disputes over South China Sea islands, as well as its unrepentant attitude toward the crimes it committed in World War II, have gravely damaged its relations with Beijing.

Seoul's acceptance of the US deploying a missile defense system, whose X-band radar can peer deep into China and Russia, on its soil has greatly threatened the strategic interests of the two countries and undermined regional stability.

Against such a backdrop, the fact that Chinese Foreign Minister Wang Yi has visited Tokyo a number of times since he took office in 2013 shows China's sincerity in wishing to cooperate with Japan and the ROK, the source said.

Although high-ranking diplomats of the three countries met in Tokyo for final deliberations about whether to hold a trilateral meeting this month, there had been pessimism that the meeting could be postponed.