Why are Russia and China squabbling over North Korea?

North Korea is a troublesome neighbour for China. At one level, its Workers' Party, led by Kim Jong-Un, claims fraternity with the Chinese Communist Party. But Marshall Kim follows his own agenda, including belligerent rhetoric against South Korea, the United States and Japan. He's also nurturing his relationship with Vladimir Putin. In this podcast, former BBC China editor Howard Zhang explains how China views the situation in the region. The host is regular presenter, Duncan Bartlett.