Some have criticised the film for largely ignoring the weapons’ destruction of Hiroshima and Nagasaki - bombed three days later, on Aug. 9, 1945.
Also causing controversy in Japan, the distributor of “Barbie”, a blockbuster released on the same day as “Oppenheimer”, latched on to fan-produced “Barbenheimer” memes that depicted the actors in the title roles alongside images of nuclear blasts.
Hiroshima was in the spotlight in May, where Prime Minister Fumio Kishida hosted a G7 summit in the western city, his home constituency.
G7 leaders issued a statement expressing their commitment to achieving disarmament but said that as long as nuclear weapons existed, they should serve to deter aggression and prevent war.
About 50,000 participants in the outdoor memorial ceremony including ageing survivors observed a moment of silence, with the summer heat hitting 30 degrees Celsius (86 Fahrenheit)
“World leaders have visited this city, seen its monuments, spoken with its brave survivors, and emerged emboldened to take up the cause of nuclear disarmament,” he said in remarks read by a U.N. representative.