Who is advising Donald Trump on foreign policy? Among both the allies and adversaries of the United States, diplomats are now racing to answer this question.

Some time back, the Foreign Ministry delivered a single photograph to a key figure at the prime minister's office. A high-ranking official from the ministry explained to the government's top leaders that the five people shown with Trump in the photograph were his foreign policy advisers. He went on to note that none of the staff at the Japanese Embassy in Washington were acquainted with them: "They are not the usual type of adviser," the official said.

His point was that, because Trump's advisers do not belong to the American foreign policy establishment, there had previously been no need to ascertain their identity.