An official in the Japanese Natural Resources and Energy Agency said the presence of methane hydrate was observed visually off the western Japanese coast.
"We have made the first step toward confirming the amount of the resource, a key step toward the commercial production of a type of methane hydrate existing in the layer of the seabed near the surface," the official was quoted by Kyodo News as saying Friday.
Methane hydrate formations are ice crystals that trap natural gas deposits under certain conditions.
Scientists working on the North Slope of Alaska last year injected a mixture of carbon dioxide and nitrogen into the underwater gas crystals to promote the release of natural gas.
The Japanese ministry official said while the resource exists in several areas of the Sea of Japan, the government can't yet confirm if there's enough for commercial development.
Japan relies completely on liquefied natural gas for its natural gas needs. The country started taking on more natural gas to meet its energy demands following the 2011 meltdown at the Fukushima nuclear power station, which was triggered by an earthquake and subsequent tsunami.
Jessica Simpson shares three-way kiss with friends in photo
Scarlett Johansson steps out with fiance after pregnancy reveal