The extraordinary complexity of the relationship between China and the US has inevitably led to them viewing one another with a jaundiced eye. Ties have frequently been unpredictable, marked by a succession of highs and lows, often rocky and rarely smooth. Given that background, it was a surprise that visits to Beijing and Washington by top officials proceeded, even after activist Chen Guangcheng escaped house arrest and fled to the US embassy, and despite the likelihood of American warplanes again being sold to Taiwan. It is a sign that Sino-US ties have come of age. Last week's trip to Beijing by US Secretary of State Hillary Rodham Clinton and Treasury Secretary Timothy Geithner for the annual Strategic and Economic Dialogue was hailed by both sides as a resounding success. Defence Minister General Liang Guanglie , who is on a six-day visit to the US, has agreed to work with it on tackling cybercrime and called the nations partners, not competitors. This is what we need to hear from the world's two most important countries. As was stressed by leader-in-waiting Vice-President Xi Jinping and US President Barack Obama after meeting at the White House in February, an all-out effort has to be made to strengthen bilateral relations. Unfortunately, in the world of diplomacy, grandiose words frequently turn out to be little more than rhetoric. This has been especially so over the years for China and the US, whose growing rivalry has shades of the cold war. Human rights and Taiwan are highly sensitive issues for Beijing, matters of internal interference when broached by outsiders. The limits have been clearly delineated and the consequences made plain. Missteps in the past have led to long-planned foreign visits being put in jeopardy and the freezing or cancelling of military co-operation. Chen's spending six days at the US embassy in Beijing overshadowed the visit by Clinton and Geithner and put human rights centre stage. But negotiations over his fate did not get in the way of the annual talks, which went ahead smoothly. They ended with the signing of investment and trade deals that were praised by Premier Wen Jiabao as 'major breakthroughs'. The setback in ties predicted by overseas experts as a result of the Chen case and a US promise to consider again selling 66 F-16 advanced fighter jets to Taiwan did not occur. A host of other impediments lie in the way of friendly relations between China and the US, among them the South China Sea, Tibet, trade, the yuan and intellectual property. But they realise they have to look at the big picture and work together on the global economy and regional issues like Iran and North Korea. They have to nourish and build on the maturity that has emerged in their relationship.