It was a stifling hot July day in 1992 when Qian Qichen, China’s foreign minister, took a helicopter to the lakeside villa of Kim Il Sung, North Korea’s leader. Qian was used to uncomfortable situations — he had sparred with Brent Scowcroft three years earlier after the massacre at Tiananmen Square — but this trip was uniquely sensitive. Qian’s task was to deliver a message to Kim from his boss, Jiang Zemin, explaining that China had decided to establish diplomatic relations with South Korea — a country that, at that point, wasn’t even shown on the maps produced in China.  It was a shocking betrayal. The Korean War enemies didn’t exactly see eye-to-eye: China saw South Korea as the traitorous neighbor that had resisted communism and fled into the arms of America, and South Korea saw China as an aggressive invader that should not be trusted. But following the end of the Cold War, China and South Korea emerged as awkward trading partners. And as South Korea’s ec