Late last night, my plane touched down here in Kagoshima, a sweltering city of 500,000 on Japan's southwestern tip. I've traveled to this historic harbor city to board the research vessel Ocean Voyager, once again, with Commander Paul Henri (P.H.) Nargeolet for another deep-ocean expedition. This time, however, P.H. and I are not collaborating on a Titanic voyage. Instead, we'll be exploring another ship tragically lost during our century – the Yamato, the biggest naval battleship the world has ever seen.

Fifty-four years ago – on the afternoon of Saturday, April 7, 1945 – the immense Yamato, pride of the Japanese navy, sank in a massive torpedo and bombing attack, one day out of Kagoshima. That day, 3,063 of the Yamato's officers and sailors lost their lives. Now, the Japanese are returning to the Yamato's wreck, with our help, to recover objects from the ship in memory of the horror and tragedy of war.

Joining us on this memorial voyage are Masami Hashimoto, 78, and Sokichi Shibagaki, 73. Both men have a personal stake in seeing that the fate of Yamato is remembered. Shibagaki lost a brother when the huge battleship sank. Hashimoto was on board the Yamato when she went down, and he was one of the few who survived the sinking.

In less than twenty-four hours, our expedition will be heading out to sea. In the meantime, P.H. is busy preparing the ship and deep-diving submersibles – just as he has for the last five Titanic research and recovery missions – and a film crew is beginning to load their gear on board.

While we're getting ready, I remember that today, too – August 15 – is an anniversary. Exactly fifty-four years ago – on Wednesday, August 15, 1945 – Emperor Hirohito, 44, made his first radio broadcast to the people of Japan. It was the very first time that the Japanese had heard their emperor's voice, and in his message, he informed them that the war was over.

Despite the atomic explosions in Hiroshima on August 6 and Nagasaki on August 9, the people of Japan were prepared to fight on for their country; already in Hiroshima, trolley cars far from the bomb's epicenter were returning to public service. But Hirohito told them that Japan must end the fighting of the Pacific War by surrender. The Emperor had spoken, the war was over, and on that day a new democratic Japan was born.

Only two weeks earlier, the Yamato's fate had been sealed when Hirohito's naval chief of staff, Admiral Koshiro Oikawa, proposed a last-ditch naval offensive to help Japan's beleaguered troops on Okinawa. As the bespectacled Hirohito patiently listened to the military plan, air force pilots were giving up their lives in desperate suicide missions, and Tokyo was still burning from the nightmarish firebombing of March 10, which claimed 83,783 lives and left more than a million people homeless.

The emperor was puzzled that the naval plan called for numerous aircraft but few ships – only the Yamato and a handful of escort destroyers. "But where's the navy?" he asked his admiral. "Have we no ships?" That was how the emperor of Japan learned that the end was near. Just one week later the Yamato, too, would be gone, sunk in under two hours by an enemy that was advancing across the sea with the largest armada of warships that has ever sailed.

In a few days, we will be revisiting the site of this tragic loss of life, off the coast of Kagoshima. We hope the objects we attempt to recover from the Yamato will help the world recall the terrible human toll of war.