Japan has been a vocal advocate of the "maximum pressure" campaign against North Korea, eschewing talks and insisting that "dialogue for the sake of dialogue is meaningless".

But with the United States, a long-time security ally, going into an unprecedented summit with the North, Prime Minister Shinzo Abe realises he has to speak directly with North Korean leader Kim Jong Un for any hope of resolving the longstanding issue of the kidnapping of Japanese citizens by agents of Pyongyang in the 1970s and 1980s.The issue was a clear priority for Mr Abe when he met privately with Mr Donald Trump at the White House on Thursday, the seventh meeting between the two leaders.