AT 6:45 ON THE MORNING OF MARCH 1, 1954, a Japanese fishing boat, the Daigo Fukuryu Maru (No. 5 Lucky Dragon), was cruising toward the Pacific Ocean’s Marshall Islands in search of bigeye tuna when crewman Matakichi Oishi saw a flash of yellow light through the porthole. “Wondering what had happened, I jumped up from the bunk near the door, ran out on deck, and was astonished,” he later wrote. “Bridge, sky, and sea burst into view, painted in flaming sunset colors.”
Oishi had just witnessed the explosion of “Castle Bravo,” a 15-megaton thermonuclear device, on the islands’ Bikini Atoll. One thousand times more powerful than the bomb that had decimated the Japanese city of Hiroshima nearly a decade before, it was the latest and most destructive in a series…
