Bikini Day is observed in Japan every March 1, commemorating the anniversary of the U.S. hydrogen bomb testing at Bikini Atoll in 1954. This event is particularly significant due to its impact on Japanese fishermen, notably the crew of the fishing boat Fukuryū Maru, who were exposed to radiation fallout from the Castle Bravo test. The explosion affected the health of the crew, leading to severe radiation sickness, and resulted in the death of chief radioman Aikichi Kuboyama. Despite initial attempts by the U.S. to cover up the incident, it eventually acknowledged its responsibility. The Fukuryū Maru is now on display in Tokyo, serving as a reminder of this tragic event. Supporters of nuclear disarmament observe Bikini Day as a national day of struggle for peace, reflecting on the consequences of nuclear testing.