RICHARD NIXON’S surprise trip to China to meet Mao Zedong in 1972 came to be known in Japan as a “Nixon shock”. Donald Trump’s choreographed meeting with Xi Jinping was not quite as shocking. But his recalibration of America’s relationship with China has sent allies and foes alike scrambling. On May 19th Takaichi Sanae, the prime minister of Japan, jetted to South Korea to meet her counterpart, Lee Jae Myung. The two were doubtless keen to swap notes on America’s shifting stance towards their imposing neighbour.