Unexpected twists in Sino-US relations were the highlight of last week's Apec summit in Beijing. Ties between the two nations warmed during the meeting as the two heads of state, Barack Obama and Xi Jinping, held candid talks.
The good news kept coming: China and the US agreed to clear tariff barriers for hi-tech products; there was a breakthrough in their 17-year negotiations on an IT agreement; and they committed to reducing greenhouse gases over the next 15 to 20 years. They also said they would extend business, tourist and student visas, while agreeing to increase mutual trust between their armed forces.
Yet such achievements did not come easily. Last year's meeting between Obama and Xi in California created a positive atmosphere, but the momentum did not last. Relations over the past year had worsened, mainly over Pacific Rim conflicts. So there were few expectations before the summit.
Xi and Obama's comments at the Apec summit show that both view Sino-US relations as very important for a peaceful, stable and prosperous Asia-Pacific region, and world. If China and the US do not work together, it may be difficult to find definitive solutions to many of today's global problems.
Their deal to cut emissions is an example of win-win cooperation, given that together the US and China produce 40 per cent of global carbon emissions. Even though China, as a developing country, strongly supports the principle of "common but differentiated responsibilities" - in which the obligation is mainly on developed nations to cut emissions - it realises it has to commit to reductions too, given the scourge of pollution at home. This is also a path to sustainable development.
The US, for its part, has been under fire for years over its lack of commitment to fighting climate change, in particular its refusal to sign the Kyoto Protocol. Xi and Obama's Apec emissions deal showcases not only their leadership abilities, but also the image of China and the US as responsible global powers. This deal may be instrumental in the signing of the UN agreement on climate change in Paris next year.
Some people on both sides of the Pacific remain pessimistic about Sino-US relations. In the past year, ties have often been at a low ebb, while Sino-Russian relations have hit new highs.
China is likely to be a major buyer of Russian gas, while Moscow is a staunch supporter of Beijing's plan to set up the BRICS Development Bank and the Asian Infrastructure Investment Bank, as well as starting the so-called Silk Road initiatives. China has said it will not join Western countries in imposing sanctions on Russia for its actions in Ukraine.
Chinese critics now claim it is the nation's most important bilateral relationship, and that the two could help break the US-led political, economic and financial order. Some have even said China and Russia should seek to contain the US.
Yet this is simply cold-war-era thinking; while Sino-Russian relations are important, China's development of relations is not aimed at any third party. More importantly, diplomacy should prioritise national interests.
Undoubtedly the Sino-US relationship is the world's most important bilateral relationship. This is reflected not only in the economic size, geopolitical influence and military strength of the two nations, but also in the vital roles they play in dealing with regional and global challenges. Xi told the Apec summit that sound China-US cooperation could act as the ballast for world stability and boost world peace.
It has been proved that when the two nations expand and deepen their cooperation in important areas, including trade, defence, anti-terrorism, law enforcement, energy, health and infrastructure, it has a positive effect on reform and development in China.
Conflicts will remain during the process of constructing Xi's idea of a new model of major power relations, but there is plenty of common ground for cooperation in areas of mutual interest; this is a sign of a maturing bilateral relationship.
At Apec, China said that plans for the Asian Infrastructure Investment Bank and Silk Road infrastructure fund are based on open and inclusive principles, and that the participation of relevant nations, including the US, would be welcomed, with a view to promoting regional prosperity.
Xi emphasised that, globally, China was a participant, builder and contributor to the current system. Obama stressed the US had no intention of containing China: "A strong, cooperative relationship … is at the heart of our pivot to Asia," he said.
Sino-US relations have had many ups and downs since diplomatic relations began in 1979. Above all, ties should be built on common interests while seeking ways to resolve their differences rationally.
The two nations will thrive if they cooperate - and suffer if they confront each other. Clearly, the Apec summit helped to deepen their mutual trust; let's hope they can continue to cooperate into the future.