Given the history of hostility between Vietnam and its former enemies China and the US, they make strange bedfellows. Yet Hanoi is now the stage for an increasingly elaborate diplomatic tango. It's a sign of the strategic shifts under way in the region as smaller countries adjust to China's rise.
Despite lingering suspicions, Vietnam has been deepening and broadening relations with its giant neighbour, with whom it shares a 1,400km land border. At the same time, Vietnam is quietly building ties with the United States - something hard to imagine a decade ago - just as Washington appears keen to cement new friendships in Asia to keep a check on China.
'We are all watching how Vietnam handles China as well as building a new strategic friendship with Washington,' said one veteran Association of Southeast Asian Nations envoy in Hanoi. 'It is fascinating stuff ... There is a view among us that if there is one country in this region that is prepared to stand up to China at times, it is Vietnam. It is going to want some new friends on board first.'
No other country in Southeast Asia has a history with China quite like Vietnam's. Close fraternal relations between their revolutionary Communist Party leaderships grew frosty as Hanoi increasingly leaned towards the Soviet bloc.
Tensions escalated into war in late 1978 as Deng Xiaoping ordered troops to invade Vietnam. The aim was to teach the Vietnamese a lesson for invading Cambodia to drive the ultra-Maoist Khmer Rouge from power.
It was a brief but exceptionally bloody campaign. Tens of thousands were killed or wounded in a month of fighting as PLA troops faced minefields and village militias who were highly motivated and battle hardened.