It hasn't happened since 2014, so when General James Mattis became the first U.S. Secretary of Defense to visit China in four years, it was set to be a news event in itself. President Xi Jinping said Beijing won't cede an inch of territory - a well-known 'red line', and a reference to the ongoing South China Sea dispute. But there was a nuanced response to Mattis, a military figure who on this trip demonstrated deft diplomatic skills. Further reading: link to Wu Zurong's opinion piece here. (At Large Podcast by China-US focus)