South Sudan seceded peacefully last year under the terms of a 2005 pact after decades of civil war, gaining control of three-quarters of Khartoum's oil output. China's long-term support for Khartoum, including its role as an arms supplier, had been a sore point with the South. But Beijing has expanded ties with South Sudan, eager to tap its oil. China can also build badly needed infrastructure in the country. That has placed China between the two hostile nations, but also given it a stake in preserving stability. http://www.reuters.com/article/2012/04/22/us-china-southsudan-idUSBRE83L04P20120422