North Korea's missile tests have put the spotlight on Beijing, which has to walk a tightrope as both Pyongyang's long-time ally and the mediator between it and the United States.
Just how tangled is the China-North Korea relationship was illustrated on Monday, when Vice-Premier Hui Liangyu flew to North Korea, ostensibly to mark the 45th anniversary of the signing of a treaty of friendship and co-operation between the two countries.
But he was accompanied by Deputy Foreign Minister Wu Dawei, who chairs the six-party talks on the North's nuclear programme. Mr Wu's presence shows that a key purpose of the mission is to defuse the current crisis and get Pyongyang back to the negotiating table with the other parties - the United States, Japan, South Korea and Russia.
Actually, last week's North Korean missile tests show just how limited Beijing's influence is. Premier Wen Jiabao had publicly warned against proceeding with the tests, but he was snubbed by North Korea.
Ever since the six-party talks began in 2003, Washington has looked to China - which provides substantial energy and food aid to Pyongyang - to use its influence and conclude a deal. However, with so much time having elapsed and a deal still elusive, some Americans suspect that Beijing is not doing as much as it could, and is simply stringing the US along.
China's job is made even more difficult by the fact that North Korea is disillusioned by continued US demands that it halt its nuclear programmes.
Chinese and American interests - just like Chinese and North Korean interests - are not identical. While some in Washington would like to see North Korea collapse and be absorbed by South Korea, Beijing wants to prop up the regime of Kim Jong-il, which acts as a buffer between it and American troops based in South Korea.
