The Natural Resources and Energy Agency said it visually confirmed that methane hydrate, a next-generation energy source, exists under the Sea of Japan off Niigata Prefecture.
The discovery, announced Friday, raises hope that more methane hydrate deposits may be found in other areas of the seabed with similar geological features off Niigata and Ishikawa prefectures, an official of the agency said.
Field surveys have identified more than 220 such potential spots in the Sea of Japan, the official said.