The maturity of China's relationship with the US was on full show during US Vice-President Joe Biden's meetings with Chinese leaders last week. Days after Beijing's announcement of its controversial East China Sea air defence identification zone, it was widely assumed that discussions would veer from their intended purpose of building co-operation and trust. Yet the issue was more a backdrop than the focus, leaving full scope to discuss how the relationship sought by presidents Xi Jinping and Barack Obama can be attained. That is how it should be. Whatever the conflicts and disagreements, no issue can be allowed to wreck ties. There is no reason why the declaration of the air zone - overlapping ones declared by American allies Japan and South Korea and also a matter of unease for Taiwan and Australia - should mar important discussions. It is China's right to create such an entity, as it has been for almost two dozen other countries. Rightly, then, its significance during Biden's talks was sidelined so that attention could be focused on the formulation of what Xi has called a "new type of great power relations" and which the US refers to as "a different kind of relationship for the 21st century". The aim is to work together to avoid conflict and past mistakes. Beijing and Washington well know this. During the almost 35 years since relations were re-established, ties have been largely positive and co-operation is taking place at a multitude of levels. Xi acknowledged during a meeting with former US president Bill Clinton last month that despite ups and downs in the relationship, it had become "a skyscraper". But no matter what heights ties attain, constant efforts have to be made to strengthen dialogue and work closer. Beijing's surprise announcement of the new zone highlighted that need, as did the revelation by Obama in 2011 of a new US military base in the northern Australian city of Darwin, part of the US "pivot" to Asia. Neither nation informed the other beforehand, deepening strategic distrust among political and military officials. It would have been far more productive to communicate the intention through established channels. While ties are mature, they are also complex. An impressive list of high-level talks have taken place since Xi and Obama held their summit in California in June, pointing to a new level of commitment. The engagement has to be strengthened and enhanced. No single incident or decision can be allowed to derail relations.