Early on March 1, 1954, the United States exploded a hydrogen bomb, code-named Bravo, on the Pacific Ocean's Bikini Atoll, in the Marshall Islands.

It was the most powerful thermonuclear device ever tested by the U.S. -- 1,000 times larger than those dropped on Hiroshima and Nagasaki -- and exposed local islanders, 28 U.S. military weather observers and 23 Japanese fishermen who happened to be near the test site aboard a tuna trawler to near-fatal amounts of radiation.

Because of the power of the bomb, which was beyond even the expectations of its designers, as well as the resulting radioactive contamination of people and the environment, the Bravo blast triggered large-scale antinuclear movements in Japan and around the world, including the Russell-Einstein Manifest.

To mark the upcoming 50th anniversary of the incident, the Tokyo museum that is now home to the 140-ton wooden trawler, the Fukuryu Maru No. 5, which is also known in English as the Lucky Dragon, began a special memorial project on Saturday in a bid to raise public awareness of the continuing threat of nuclear weapons.

"I think it is important to get back to the starting point now that political, moral and technological brakes on nuclear weapons appear to be uncertain," said Shoichiro Kawasaki, president of the Daigo Fukuryu Maru Foundation, during a ceremony to open the exhibition.

The foundation is entrusted by the Tokyo Metropolitan Government with the management of the Daigo Fukuryu Maru Exhibition Hall, in Tokyo's Koto Ward.

Amatlain E. Kabua, the Marshall Islands ambassador to Japan, attended the opening ceremony and said "Marshall islanders have suffered the same" as the Japanese, adding that "the tragedy should never be repeated again."

The exhibition hall has renovated its main display hall, detailing the Bravo blast as well as the history of nuclear weapons with colorful panels and updating descriptions.

Over the coming year, it will hold special photo exhibitions featuring the lives of people in the Marshall Islands, where the U.S. conducted a total of 67 nuclear tests between 1946 and 1958, and display letters sent from around the nation to the hospitalized crew members of the Fukuryu Maru No. 5.

The museum also plans to dispatch mobile exhibitions to a number of cities around Japan, including Yokohama, Kyoto and Yaizu, Shizuoka Prefecture, from June.

"We may no longer see such a large-scale nuclear test as was carried out at Bikini," said Kazuya Yasuda, secretary general of the Daigo Fukuryu Maru Foundation, but the issue of nuclear weapons "has never been solved and continues in a different form," he said, citing the fact that there are some 20,000 nuclear weapons still deployed around the world.

Yasuda also referred to U.S. plans to deploy miniature nuclear weapons -- a move widely seen as blurring the traditional boundaries between conventional and nuclear weapons.

The museum opened in 1976 as a result of citizens' efforts to preserve the Fukuryu Maru.

After radioactivity levels aboard the vessel had decayed to a safe level, the tuna trawler was moved in 1956 to the Tokyo University of Fisheries as a training ship.

After 10 years of service, the ship was sold to a scrap dealer and was eventually abandoned at Yumenoshima, in Tokyo.

Citizens learned of the ship's fate through media reports and launched a campaign to preserve the vessel, resulting in the establishment of the museum with the trawler displayed as a symbol of peace and a world free of nuclear weapons.

The Daigo Fukuryu Maru Exhibition Hall is located in Yumenoshima (Island of Dreams) Park, a 10-minute walk from Shinkiba Station on the JR Keiyo Line or the Subway Yurakucho Line.

It is open between 9:30 a.m. and 4 p.m., except Mondays. Admission is free. For more information, call the secretariat at (03) 3521-8494 or e-mail [email protected]