By Louisa Lim
BBC correspondent in Beijing
China wants to see the crisis resolved through diplomacy
As host of talks over North Korea's nuclear programme, China has invested a lot of diplomatic energy in getting all six parties to the negotiating table.
Analysts say such a proactive role marks a significant departure in Chinese foreign policy.
But why has China decided to act now and how far will it push its ally, North Korea?
That these talks are taking place at all is largely due to China's diplomatic efforts.
During months of painstaking lobbying, Chinese envoys shuttled between Pyongyang and Washington to try to find a format acceptable to both sides.
Beijing also hosted trilateral talks in April and analysts say the failure of those talks was one of the factors pushing forward China's latest diplomatic offensive.
But the new proactive policy has come from the very top of the government, indicating a closer integration into the international community. China has won praise from world leaders for its efforts.
China has traditionally called its relationship with North Korea as close as lips and teeth.
But in recent months Beijing has hardened its line, saying it is opposed to nuclear weapons on the Korean Peninsula.
The real question now is how much influence Beijing will be willing to bring to bear on Pyongyang.
China supplies its northern neighbour with around 70% of its fuel and much of its food aid - giving Beijing some leverage with the North Koreans.
Earlier this year, diplomats say Beijing cut off the oil pipeline to North Korea for several days, claiming technical problems.
But Beijing says it opposes sanctions and would be wary of taking any steps that might destabilise North Korea.
The two countries share a border and China would not like to see large numbers of North Korean refugees fleeing into its territory.
Chinese officials have repeatedly emphasised that they would like to see this crisis solved by diplomacy alone and analysts here are down playing expectations for the talks, saying the best outcome would be an agreement to hold another round of negotiations.