Japan Knew America's WWII Bombs Weren't Exploding

In August 1944, the U.S. Army Air Forces printed a sentence in its own intelligence summary that most air forces would never have printed at all: the statement as to duds among parachute frag bombs is correct. The Japanese had been saying American bombs were landing in the dirt and doing nothing. The Americans agreed — and then explained why. The answer was not sabotage, not a bad batch, and not the tail-strike legend repeated for eighty years. It was six tenths of a second, inside a mechanism the size of a fist.