The Maritime Self-Defense Forces submarine brushed against a tanker carrying chemicals as it surfaced about 30 miles (50 kilometers) off the southeastern coast of Miyazaki, on the southern island of Kyushu, a defense agency spokesman said on condition of anonymity by protocol.
The civilian vessel was later identified as the Panamanian-registered 4,000-ton Spring Auster, en route to China, Coast Guard spokesman Takatoshi Nagasaki said.
None of its crew of 16 Philippine nationals and a South Korean was hurt, but the extent of the damage was not immediately known, he said.
No injuries were reported among the 75 crew on the submarine Asashio. It apparently hit the ship's hull while surfacing, and the top part of the submarine's aft fin had been dented by the impact, the defense spokesman said.
The cause of the accident was not immediately known. The submarine had re-submerged and was expected to enter a nearby defense port for inspection, he said.
Coast Guard officials made radio contact with the Spring Auster, whose crew reported feeling a small impact. They maintained course because no other vessel was in sight, Nagasaki said.
No leakage was reported from the tanker, which would be inspected by Coast Guard officials at a nearby port, the defense spokesman said.
Near the United Nations Glass Palace in New York, there is a metallic sculpture entitled "Evil Defeated by Good", representing Saint George transfixing a dragon with his lance. It was donated by the USSR in 1990 to celebrate the INF Treaty concluded with the USA in 1987