Daigo Fukuryū Maru

Early days and final voyage

Built in March 1947, and launched from Koza, Wakayama, the boat's name was originally Dainana Kotoshiro Maru (第七事代丸, Kotoshiro Maru No. 7)/Kotoyo Maru No. 7. Under this title it was a bonito boat and moored in Misaki Fishing Harbor, Kanagawa Prefecture.

It was later remodeled into a tuna fishing boat. In 1953, it moved to Yaizu Port, Shizuoka Prefecture, with a new name, Daigo Fukuryū Maru translated as - Lucky Dragon No. 5, or alternatively, the Fifth lucky Dragon.

Under its new title, the Lucky Dragon No. 5 took five ocean voyages. Its fifth and final voyage began on January 22, 1954, and ended on March 14 of that year. The crew initially set off to go fishing in the Midway Sea near Midway atoll but when they lost most of their trawl nets to the sea, they altered their course southward near the Marshall Islands, and encountered fallout from the Bikini atoll located Castle Bravo nuclear test on March 1.

A map of the varying location of the boat in the days leading up to and after the day of the explosion is available. On March 1, the map depicts the vessel very near to the border of the US Navy issued "danger zone notice" dated 10.10.1953. Following March 1, the vessel charted a practically straight/ geodesic course back to its home port of Yaizu, passing the same latitude as Wake Island between March 4 and 6 and arriving at Yaizu Japan, March 14.

The source of the map, does not state how the map was created, that is, it does not state that the ship's log was consulted in the creation of the map nor does it provide the navigator's measurements with the compass and sextant of the period. Therefore, the exact position of the ship on the day of the explosion is uncertain. Contemporary references give a figure of "80 miles east of Bikini Atoll" without stating the method by which the distance was computed. According to a 1997 paper by Martha Smith-Norris, the ship was operating "14 miles" outside the 57,000 square mile "Danger Area", and it was not detected by radar or visual spotter planes.

Events surrounding March 1, 1954

The Daigo Fukuryū Maru encountered the fallout from the U.S. Castle Bravo nuclear test at Bikini Atoll, near the Marshall Islands, on March 1, 1954. When the test was held, the Daigo Fukuryū Maru was catching fish outside the danger zone which the U.S. government had declared in advance. However, the test was more than twice as powerful than it was predicted to be, and changes in weather patterns blew nuclear fallout, in the form of a fine ash, outside the danger zone. On that day, the sky in the west lit up like a sunset. Seven minutes later the sound of the explosion arrived, with fallout reaching the ship two hours later. The fishermen realized the danger, and attempted to escape from the area, but they took time to retrieve fishing gear from the sea, exposing themselves to radioactive fallout for several hours.

The fallout - fine white flaky dust of calcinated Bikini Island coral, which absorbed highly radioactive fission products and neutron activated isotopes - fell on the ship for three hours. The fishermen scooped it into bags with their bare hands. One fisherman, Matashichi Oishi, reporting that he "took a lick" of the dust that fell on his ship, describing it as gritty but with no taste. The dust stuck to surfaces, bodies and hair; after the radiation sickness symptoms appeared, the fishermen called it shi no hai (死の灰, death ash).

Events between March 2–14

Feeling ill, the crew set sail to return to Yaizu on March 2, and arrived on March 14.

Events after return to Yaizu port

Japanese biophysicist Yasushi Nishiwaki immediately traveled from Osaka to Yaizu to examine the crew and their boat. He quickly concluded that they had been exposed to radioactive fallout and wrote a letter to the chief of the US Atomic Energy Commission (AEC) asking for more information on how to treat the crew. The crew members, suffering from nausea, headaches, burns, pain in the eyes, bleeding from the gums, and other symptoms, were diagnosed with acute radiation syndrome and admitted to two Tokyo hospitals. On September 23, chief radio operator Mr. Aikichi Kuboyama, 40, died — the first Japanese victim of a hydrogen bomb. He left these words: "I pray that I am the last victim of an atomic or hydrogen bomb." The US did not respond to Nishiwaki's letter or to letters from other Japanese scientists requesting information and help, although the United States did dispatch two medical scientists to Japan to study the effects of fallout on the ship's crew and to assist their doctors.

The US government refused to disclose the fallout's composition due to "national security", as the fallout's isotopic ratios—namely a percentage of uranium-237—could reveal the design of the Castle Bravo device through radio-chemical analysis, with this information having a history of being regarded as potentially revealing the means by which megaton yield nuclear devices achieve their yield. For instance, Joseph Rotblat may have deduced the staging nature of the device by studying the ratio and presence of tell-tale isotopes present in the fallout. As of 1954, the Soviet Union had not yet been successful with thermonuclear staging and such information could have assisted in their development of a thermonuclear weapon. Lewis Strauss, the head of the AEC, issued a series of denials; he also hypothesized that the lesions on the fishermen's bodies were not caused by radiation but by the chemical action of the caustic burnt lime that is produced when coral is calcined, that they were inside the danger zone, and told President Eisenhower's press secretary that the Lucky Dragon #5 may have been a "Red spy outfit", commanded by a Soviet agent intentionally exposing the ship's crew and catch to embarrass the USA and gain intelligence on the test's device.

Later, the United States expanded the danger zone and it was revealed that in addition to the Daigo Fukuryū Maru, many other fishing boats were in the expanded zone at the time. It is estimated that about one hundred fishing boats were contaminated to some degree by fallout from the test. Despite denials by Lewis Strauss concerning the extent of the claimed contamination of the fish caught by Daigo Fukuryu Maru and other ships, the FDA later imposed rigid restrictions on tuna imports.

At first the US claimed that the extent of the Lucky Dragon incident contamination was trivial. Later the United States paid Kuboyama's widow and children the equivalent in yen of about $2,800 ($25,000 in 2017). The tragedy of the Daigo Fukuryū Maru gave rise to a fierce anti-nuclear movement in Japan, rising especially from the fear that the contaminated fish had entered the market. The Japanese and U.S. governments negotiated a compensation settlement, with the transfer to Japan of a compensation of $15,300,000, of which the fishery received a compensation of $2 million, with the surviving crew receiving about ¥ 2 million each, ($5,550 in 1954, $49,500 in 2017). It was also agreed that the victims would not be given hibakusha status. The Japanese government also acknowledged that it would not pursue further reparations from the U.S. government.

Medical symptoms and treatment

The majority of medical experts believe that the crew members were infected with hepatitis C through blood transfusions during part of their acute radiation syndrome treatment.

The longest staying crew member spent about a year in hospital following their return to port.

Health history of crew

Like the hibakusha, survivors of atomic bombings in Hiroshima and Nagasaki in 1945, the Lucky Dragon crew were stigmatized because of the Japanese public’s irrational fear of those exposed to radiation (it was commonly believed to be contagious). The crew tried to stay quiet about their exposure for a number of decades, beginning with their discharge from hospital. A number of the crew also had to move away from their previous places of residence to get a fresh start.

Former crew members include the 87-year-old, as of 2014, Susumu Misaki, who opened a tofu shop after the incident.

Twenty years old at the time, Matashichi Oishi, who is reported to have licked the mysterious fallout substance which fell on his ship in March, 1954 as a taste test to ascertain its properties, was 79 years old in August 2013. After the exposure, he left his hometown to open a dry cleaning business. Beginning in the 1980s, he frequently gave talks advocating nuclear disarmament. In 2011, he published a book titled, "The Day the Sun Rose in the West: The Lucky Dragon and I."

Radioactivity of the ship post contamination

The Daigo Fukuryū Maru was deemed safe for public viewing and was preserved in 1976. It is now on display in Tokyo at the Tokyo Metropolitan Daigo Fukuryū Maru Exhibition Hall.

Media

The Toho Film Gojira (Godzilla, 1954), was inspired in part by this event.

A poem Japon Balıkçısı (The Japanese Fishermen) was written in 1956 by Turkish poet Nâzım Hikmet Ran about the events.

Ralph Lapp wrote The Voyage of the Lucky Dragon which was published in 1958. It was reviewed on the front page of The New York Times Book Review.

A film version of the events, Daigo Fukuryū Maru (1959), was directed and screenwritten by Kaneto Shindo, and produced by Kindai Eiga Kyokai and Shin Seiki Eiga.