BEIJING, March 20 -- China-U.S. relations seem to have found a good rhythm, as U.S. Secretary of State Rex Tillerson wrapped up his visit to China.

While Chinese President Xi Jinpingsaid China and the United Statescould become "good cooperative partners," and that "cooperation is the only correct choice for both countries," Tillerson vowed that the U.S. side is ready to develop relations with China based on the principles of non-confrontation, no conflict, mutual respect and win-win cooperation.

Tillerson's reiteration of the important principles originally proposed by China in 2013 is a positive sign for China-U.S. relations, in which cooperation should always prevail.

Despite earlier inappropriate words and actions from the U.S. new administration, which had led to worries and doubts about U.S. adherence to the one-China policy, things have gradually come back on track.

In a phone conversation on Feb. 10, President Donald Trump said the U.S. government adhered to the one-China policy, reversing his previous stance and sending a positive signal for bilateral relations.

Engagement between China and the United States has been moving forward since 1972 when U.S. President Richard Nixon paid a historic visit to China. Over the last four decades, cooperation has been the mainstream in bilateral ties, despite twists and turns.

Two-way trade of goods surged from 1 billion U.S. dollars in the 1970s to 500 billion dollars in 2016. China has become the largest trading partner of the United States, while the United States is China's second-largest trading partner.

Meanwhile, China-U.S. bilateral trade and investment helped create about 2.6 million jobs in the United States in 2015 across a host of U.S. industries from automobiles and construction equipment, to agriculture.

Cooperation between Beijing and Washington has been highlighted in joint efforts on climate change and in handling of the Iranian nuclear issue.

These hard-won achievements should be appreciated and valued, especially at a time when the Asia-Pacific and the wider world are facing a thicket of thorny issues that require close coordination between the two countries, such as the tense situation in the Korean Peninsula.

Cooperation has prevailed over confrontation for four decades, leading to prosperity in both countries and delivering benefits to the world at large. Let us hope for more optimistic signs on the heels of Tillerson's visit.