JOGMEC said that the gas was extracted from deposits of methane hydrate, which is a frozen gas, also known as "flammable ice", near Japan’s central coast.

The trade ministry of Japan said the production tests will be carried out for nearly two weeks, which will be followed by tests on how much gas has been produced, reported Reuters.

The country, which has been importing most of its energy to meet domestic demand since 2001, has invested hundred million dollars to develop the technology to tap methane hydrate reserves off its coast.

According to a Japanese study, it is estimated that about 40 trillion cubic feet (1.1 trillion cubic meters) of methane hydrates can be found in the eastern Nankai Trough off the country’s Pacific coast.

Methane hydrate is developed from a mixture of methane and water deploying certain pressure and conditions.

Since methane is an important component of natural gas, governments of several countries including Canada, US, Norway and China, are exploring possibilities to harness hydrate deposits as an alternate energy form.

In 2008, the company used the depressurisation method for the first time to produce methane gas, for continuous six-day period, from hydrate reserves held deep in permafrost in Canada.

Japan relies on the depressurisation technology to transform methane hydrate to methane gas as a more effective process than using the hot water circulation method.

In February and March 2012, JOGMEC conducted preparatory works including drilling a production well and two monitoring wells.