With the end of his US presidency in sight, Barack Obama is racking up a series of legacy-friendly trips. Fresh from his historic visit to Cuba in March, Mr Obama will become the first sitting US president to go to Hiroshima later this month.

Mr Obama will use his visit to the city’s memorial, which honours those killed by a US atomic bomb in 1945, to discuss his vision of a nuclear-free world, but he will also use it as an important step towards cementing the alliance between the US and Japan. The former enemies are now at the centre of a web of relationships and links in Asia aimed at restraining China.

From Japan, Mr Obama is due to travel to Vietnam, another one-time foe that is seeking US assistance as it tries to come to terms with Beijing’s growing influence in the South China Sea and its campaign to build artificial islands.