When China broke out one of its “big guns” in last year’s trade war with the US – an array of export controls on rare earth elements – it helped spur a temporary truce in the pitched conflict between the two economic superpowers.After Beijing’s announcement, many around the world expressed shock at the size and scope of China’s response to Washington’s sky-high tariffs. But for Japan, a squeeze on rare earth shipments was not so novel a concept.In 2010, following the collision of a Chinese...