Japanese Prime Minister Sanae Takaichi’s revival of Tokyo’s claim to islets whose symbolic weight far outweighs their size has rekindled an old dispute that may play well with nationalist supporters at home, but risks derailing hard-won diplomatic progress abroad. Seoul swiftly shot down Takaichi’s assertion last week that the rocky outcrops, known as Takeshima to Japan and Dokdo to South Korea, belong to Tokyo. “Dokdo is clearly our inherent territory,” the presidential office said in a...