Japan’s Prime Minister Shinzo Abe announced Friday he will resign over health problems, in a development that kicks off a leadership contest in the world’s third-largest economy. “I have decided to step down from the post of the prime minister,” he told a press conference, saying he was suffering from a recurrence of the ulcerative colitis that ended his first term in office. Abe said he was receiving a new treatment for the condition, which needed to be administered on a regular basis which would not leave him with sufficient time...