Hong Kong (CNN) Could an old map bring Asia to the brink of war?

An international tribunal ruled Tuesday that China's nine-dash line -- drawn on a map dating from the 1940s that claims large stretches of the South China Sea -- has no legal basis.

It was an eviscerating verdict for Beijing, which has long claimed it has unique, historical rights to the disputed waters which are rich in resources and a busy thoroughfare for international shipping.

"It will certainly intensify conflict and even confrontation," said Cui Tankui, China's ambassador to the United States, in a speech in Washington.

Analysts say the ruling, which went overwhelmingly in favor of the Philippines, narrows China's wiggle room for negotiation in the dispute.

"It will further escalate nationalist sentiment in a big nation like China," said Wang Jiangyu, law professor with the National University of Singapore.

"In fact, it has immediately forced many of China's moderates to become hawks."

Risk of miscalculation

Ashley Townshend, research fellow at the U.S. Studies Centre at the University of Sydney, said that if the ruling had been a less emphatic victory for the U.S.-allied Philippines, then it may have proved a "bit of a firebreak" for regional tensions, opening up space for negotiation over the issue.

Instead, the international tribunal delivered a resounding verdict against Beijing, and in response, China might be less concerned with managing its reputation in the eyes of the world, and less troubled about being seen as an international lawbreaker.

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Anton Alifandi, principal Asia analyst for IHS, said the big worry was that there would be an interstate war involving the major powers -- the U.S., China and the countries of southeast Asia.

But, he said, the stakes were so high that it was highly unlikely in the medium term that China would deliberately escalate tensions to a point where the U.S. would retaliate -- as to do so would lead to a defeat for China, and a loss of legitimacy.

However, he said, "there is always a risk of miscalculation, that is the danger."

"If one side plays brinkmanship and thinks the other side will back down and you miscalculate, things can get out of hand quite quickly."

'First act'

Townshend said that it was in no-one's interest that the region -- which has $5 trillion worth of trade pass through its waters annually -- become the setting of a next global conflict between China and United States.

"But it would be a mistake to argue that the risks are low. The risks are high," he said.

He said that China would be "acutely aware of the risks of unintended escalation," but it would now be under domestic pressure to register its defiance of the verdict and demonstrate that it had no intention of changing its position.

Shen Dingli, professor and associate dean at the Institute of International Studies at Fudan University in Shanghai, said China's behavior in the South China Sea, where it's turned sandbars into islands equipped with military airstrips, was unlikely to change.

However, he saw hope in the Philippines' surprisingly muted reaction to the verdict.

The country's foreign secretary spoke for only two minutes Tuesday at a press conference, calling it a milestone decision that experts were now analyzing.

"The Philippines has exercised restraint and didn't issue an aggressive statement," said Shen.

"The verdict is the first act. The second act could be more promising if it involves negotiation."

It's a view that was raised Wednesday by Liu Zhenmin, China's vice foreign minister. He hoped the Philippines would view the ruling as a "scrap of paper" so bilateral negotiations could resume.

Chinese FM: China has noted the positive statements by President Rodrigo Duterte, and stands ready to work with the new Philippine gov't — CCTVNEWS (@cctvnews) July 13, 2016

Bitter pill

Nonetheless, to be told by the court that Beijing was at fault and the U.S.-allied Philippines was the aggrieved party, would be "a massively bitter pill for China to swallow," said Townshend.

"We're talking about a country that genuinely believes in the historical narrative that it has presented and that has very strong nationalist overtones," he said.

"It's a country that is more than anything sensitive to being humiliated, especially at the hands of what it sees as European imperialists. That's a very strong motivator for their actions in the South China Sea."

China published a map in 1948 outlining its claims in the South China Sea. The map becomes the basis of the "nine-dash line" -- the foundation of China's current territorial claims.

The Asia Maritime Transparency Initiative, an initiative at the Center for Strategic and International Studies that monitors developments in the region, said in a briefing paper that acts of retaliation could include increased island-building activities, a blockade of Philippines marines, such as had been carried out in 2014, or the declaration of an Air Defense Identification Zone (ADIZ) over the South China Sea.

As when China declared an ADIZ over the East China Sea in 2013 , other powers could quickly move to defy the zone, but civilian air traffic would likely comply. Such a move would increase the risk of incidents between air forces, it said.

Asserting what China sees as historical rights in the South China Sea has been a massive priority for President Xi Jinping, said Shen.

"China used to be brutalized by other powers. The British sold us opium, Japanese raped Nanjing. These bad memories still affect us. As China rises, we ought to restore these rights," said Shen.

"We were the first to discover the place in the entirety. We have maps, books and records. For three decades our claims met no challenge or confrontation."