Totally unknown until the 1960s, methane hydrates could theoretically store more gas than all the world's conventional gas fields today. The amount that scientists estimate should be obtainable comes to about 43,000 trillion cubic feet, or nearly double the 22,800 trillion cubic feet of technically recoverable traditional natural gas resources around the world. The United States consumed 26 trillion cubic feet of gas last year.

That raises the possibility of an energy revolution that could dwarf even the shale gale that has transformed America's fortunes in a few short years. It could also potentially have big implications for countries, including the US, Australia, Qatar and even Russia, which are banking on unbridled growth in the global trade of liquefied natural gas. The trick will be to figure out exactly how to profitably tap vast deposits of the stuff buried inside the sea floor.

"There's no doubt that the resource potential is enormous," says Michael Stoppard, managing director, global gas, at energy consultancy IHS. "I think it's the ultimate rebuttal to the peak oil and peak gas concept, but of course that's not much good unless you can develop it."

To that end, this month a 499-tonne survey vessel nosed out of the port of Sakai, once home to fabled gunsmiths and the finest makers of samurai swords in medieval Japan and today the prospective launching pad for a new technological revolution.

For the next two months, the Kaiyo Maru No 7 will survey the sea floor off Japan's west coast, the first step in a years-long process that could end with significant production of natural gas in Japanese waters. A promising methane hydrate site off the southeast coast was the subject of earlier surveys.

Japan is the epicentre of methane hydrates today not because it has so much of the resource - quite the opposite, most methane hydrates appear to be in North America - but because it needs the resource so badly and is working faster than any other country to make fire ice a commercial proposition.

The US and Canada are awash in methane hydrate resources, found both under the seabed such as in the Gulf of Mexico and in sub-Arctic permafrost. But both countries also have huge reserves of conventional and shale gas, dampening industry enthusiasm for a complicated, lengthy research process.

Although some companies, such as Chevron, work alongside the US government on methane hydrate research, "there's a little less space in the industry for enabling field experiments and data collection than there was 10 years ago," says Ray Boswell, technology manager for methane hydrates at the US Energy Department's National Energy Technology Laboratory.

Not so in Japan. This spring, researchers in Japan reached a technical breakthrough, figuring out exactly how the gassy bundles of ice release 160 times their volume in methane as they are taken out of low-temperature, high-pressure environments. That could make commercial extraction, which experts estimate is at least 10 to 15 years off, an easier proposition.

Japan has sought a new energy blueprint in the wake of the 2011 nuclear disaster that shuttered the country's nuclear reactors, which led to a spike in imports of expensive fuel, especially natural gas. Japan's new energy plan, approved in April, puts nuclear power back on the table. But officials concede that nuclear energy will likely never reach the 30 per cent of Japan's electricity output that it was before the disaster.

As a result, the government included methane hydrate development in its top five priorities for new energy supplies. Japanese officials say they are working on methane hydrates because they need an alternative to liquefied natural gas (LNG), which costs about three times as much as natural gas in the US.

"It's very easy to understand the Japanese motivation, and with China, India and South Korea you have very similar situations," says Tim Collett, a gas hydrate expert at the US Geological Survey.

Because Japan and South Korea are the first- and second-largest importers of LNG globally, methane hydrate development "is potentially a significant long-term threat to the LNG industry," says IHS's Stoppard. "Even small-scale development of methane hydrate would slow down any growth in LNG sales there."

The kinds of shale gas reserves that have made the US an energy superpower exist elsewhere too. China is loaded with shale resources, as are parts of Europe and Latin America. But the shale gas revolution depends on small, nimble energy companies, thousands of drilling rigs, private ownership of land, and up-to-date financial and regulatory systems.

Getting methane hydrates out of the sea floor should be simpler, and because for now it requires close co-operation between industry and governments, it seems well suited to economies in the Pacific Rim.

The problem with methane hydrates isn't exactly technological. Conventional drilling techniques, rather than some fancy breakthrough, will likely enable producers to tap undersea deposits, remove the gas from the icy lattice that traps it, and pump it to the coast.

The problem is figuring out how to do so economically. All possible techniques for extracting gas from the hydrates - such as raising temperatures to release the gas or depressurising the deposits - have their drawbacks. There are also other complications not found in conventional gas wells: the melting ice releases huge amounts of water, which producers must deal with, potentially raising costs.

And deposits are found at lower pressure than conventional gas deposits, meaning it will require more energy (and money) to pump the gas to where it needs to go, even if that makes less likely the prospect of catastrophic blowouts, like the one suffered by the BP-leased Deepwater Horizon drilling rig four years ago.

That's why Collett and Stoppard say it will be 10 to 20 years before gas hydrates are extracted at commercial scale and make up a significant part of the energy mix.

Even if the commercial development of gas hydrates is a generation away, they could still become a factor in territorial disputes in the South China Sea and the East China Sea, where Beijing has faced off with countries such as the Philippines and Japan. That's because methane hydrate potential comes on top of the conventional oil and gas riches that are believed to lie underneath those waters.

While some experts estimate that the sheer size of the potentially abundant energy resources will serve to de-escalate tensions in the region, others worry that it will just add fuel to the fire.

"Abundance in and of itself won't remove the deeply political dimensions of these disputes," which tend to revolve around problems of sovereignty over barren chunks of land, says Ely Ratner, deputy director of the Asia-Pacific Security Programme at the Centre for a New American Security.