Debris scattered over a large area at the bottom of sea in the Philippines indicate that the massive Japanese battleship Musashi blew up in an undersea explosion after it sank 70 years ago.
Experts from a research team analysing a live feed from an unmanned submersible said they believe the Musashi suffered at least one explosion while sinking to the 3,280ft deep seafloor.
The two and a half hour feed provided the first detailed images of the Second World War ship, which sank in October 1944.
The research team, sponsored by Microsoft co-founder and entrepreneur Paul Allen, found the remains of the ship last week after searching for eight years.
The Musashi, one of Japan's biggest and most famous battleships, sank in the Sibuyan Sea in the central Philippines during the Battle of Leyte Gulf, losing half of its 2,400 crew. It was last seen disappearing into the water in one piece after being struck by torpedoes, but what happened subsequently was never known.
"The wreck is actually very damaged," said David Mearns, a marine scientist on the team. "It appears she suffered at least one, if not two, magazine explosions which would have sheared off the bow and the stern, and its entire middle section of its super-structure."
The footage showed fish and other marine creatures swimming by the rusted debris scattered over a wide area, some chunks covered by coral.
There were holes in the bow area, apparently made by US torpedoes, and the ship's stern is upside down. A propeller is torn off from a shaft and gun turrets and catapults are broken off.
The feed also showed a round teak base on the bow that held the Imperial chrysanthemum seal that only a few battleships were allowed to carry - a key finding that convinced Japanese experts and some survivors that this was the wreck of the Musashi.
Historian Kazushige Todaka, head of the Yamato Museum and an expert on warships, said he was "100% positive" the ship is the Musashi.
He said the upright bow section and the upside-down stern mean the ship had an explosion.
"It shows there was a tremendous impact that tore the ship apart," he said.
Closer examination of the video would help explain what happened to the ship as it sank to the sea bottom, he said. He also hoped this would lead to discovery of other sunken warships that are unaccounted for.
Shigeru Nakajima, a 94-year-old former electrical technician on the Musashi, one of only a few hundred aboard who made it safely back to Japan, said he was deeply moved by the footage he saw at a community centre near his home in Kashiwa, near Tokyo.
"The captain and those who went down (with the Musashi) must be delighted in heaven by the news of the discovery," he said.
The team says it is collaborating with the governments of Japan and the Philippines over the wreckage. Experts say it would be difficult to pull up the ship, though technically it might be possible. Some people consider the wreckage as a place where the spirits of the victims rest and should be left at peace.