Beijing has underscored that the Taiwan question is the key to relations between China and Japan at the latest high-level dialogue of their policymakers, because it is the basis of fundamental trust and credibility in the bilateral relationship.

Observers noted that Japan fueled tension in its already frayed ties with China when it joined the recent statement of the G7 denouncing China's military drills following the provocative visit by US House Speaker Nancy Pelosi to Taiwan earlier this month.

"Taiwan is an inseparable part of China," Yang Jiechi, director of the Office of the Foreign Affairs Commission of the Communist Party of China Central Committee, told Takeo Akiba, secretary-general of Japan's National Security Secretariat, on Wednesday.

The two senior officials were chairing the ninth high-level political dialogue between China and Japan in Tianjin.

Tokyo should keep an eye on the fundamental and long-term interests of the two countries and their people, hold a proper perspective of China and follow through on a positive, pragmatic and reasonable China policy, Yang said.

The dialogue is a vital mechanism for strengthening high-level strategic communication between the two countries and was initiated in 2015. Nearly 18 months have passed since the eighth dialogue in Tokyo in February last year.

This year marks the 50th anniversary of the normalization of bilateral relations between the two countries.

Japan is expected to stay true to the right path of peace and development, staunchly honor the four landmark political documents and political consensus reached by the two countries and work with China to strengthen mutual political trust, Yang said.

Tokyo should break away from the zero-sum way of thinking, properly manage divergences and make the bilateral relations more mature, stable, healthy and resilient, he added.

According to the Foreign Ministry, the two sides agree that the dialogue was candid, in-depth and constructive, having reached a measure of some consensus and will continue dialogue and communication.

The meeting on Wednesday shows Beijing's sincerity in keeping bilateral relations afloat as some hawkish political figures in Japan seek to decouple from China economically and in other areas, the experts said.

"With the bilateral collaboration developing over the past 50 years, the two countries have formed intertwined bonds of interests. Cooperation is a necessity for both sides, particularly amid the COVID-19 pandemic, and a complete decoupling does not serve the interests of either side," said Yang Bojiang, director of the Chinese Academy of Social Sciences' Institute of Japanese Studies.

Although there are increasing signs of friction or contradictions between the two sides, they should not run into the deadlock of a full confrontation and competition, Yang added.

During the Wednesday meeting, Beijing highlighted the need for both sides to insist on their own convictions and "rule out internal and external disturbances". Peaceful coexistence and friendly cooperation are the only right choice for bilateral relations.

"The strengthening of the Japan-US alliance targeting China has constituted a lasting disturbing factor for the China-Japan relationship," said Yang, the CASS scholar.

Liu Jiangyong, a professor of Japan studies at Tsinghua University, said: "The rising tension between China and the United States leads to changes of Japan's external climate. The Japanese government has firmly sided with the US and has taken advantage of the China-US feuds, leading to Tokyo's rising hostility against China."

Liu said that the structural contradictions between the two countries over historical and territorial issues and the Taiwan question have seriously affected bilateral political relations.

The Cabinet of Prime Minister Fumio Kishida has embarked on hawkish diplomacy toward China, he noted, saying that Tokyo has publicly accused Beijing of "changing the status quo" by reinforcing patrols around China's Diaoyu Islands.

The deterioration of Japanese public opinion and attitudes toward China has prompted more Japanese politicians to take a hard-line approach against China, Liu added.