Japan’s hopes for a visit by Donald Trump during his trip to Asia next month may be hanging in the balance as relations between China and the United States steadily improve. The US president spent three days in Japan ahead of last year’s Asia-Pacific Economic Cooperation summit, and his meeting with Prime Minister Sanae Takaichi was hailed as a sign of a “new golden age” in the countries’ relationship. But since then Trump’s growing rapport with his Chinese counterpart Xi Jinping has caused...