It is hard to overestimate the stakes involved in the disputed South China Sea.
All the major powers are involved. A rising and resource-hungry China claims much of the area through its historic claim to the Spratlys archipelago in the deep south - it dates its occupation of the islands to the Han dynasty. Despite China's increased military spending, the US remains the leading military power and will be for more than a decade at least - projecting its influence through the carrier battle groups of the Seventh Fleet, frequent visitors to Hong Kong. Japan receives much of its oil via the South China Sea's shipping lanes, while Russia is seeking to expand its long-time oil interests off Vietnam.
Vietnam, a much smaller player, straddles the equation, the only other nation to claim the entire Spratlys - jurisdiction it bases on its large continental shelf and the UN's Convention on the Law of the Sea.
It is a nation defined by its wars of independence - including modern conflicts against both the US and China - and one fiercely protective of anything it regards as sovereign. It doggedly refers to the South China Sea as the 'Eastern Sea' in all official communications, maps and state media reports. And it, too, is determined to fully exploit the oil, fishing and tourism potential of its coast - oil and gas are already its leading export earners. Vietnam's desire for economic sustainability and independence is matched by a foreign policy geared to ensuring it is never beholden to a single alliance or relationship. It wants better ties with both China and the US, for example, but not at the expense of each other.
This complex web of interests is the backdrop to the news we report today that executives from ExxonMobil - the world's largest oil firm - have been approached by Chinese envoys and told to pull out of preliminary oil deals with Vietnam.
Some independent analysts suspect Beijing is manoeuvring to muscle its way into a future joint-development deal, similar to the one hatched recently between Japan and China to end years of tension over the East China Sea. Others suspect also that China could be showing its unhappiness with Vietnam, a fraternal Communist Party-ruled ally, but one deeply suspicious of its giant neighbour to the north.
In a statement to the Sunday Morning Post, Vietnamese Foreign Ministry spokesman Le Dung suggested there was little room for compromise over oil, even if he avoided the bellicosity that has occasionally marked Hanoi's protests to Beijing, couching China in deliberately 'foreign' terms.