Hardly a year goes by that new construction in London, or Berlin or Dresden doesn’t turn up an unexploded bomb. I wonder why we never hear about unexploded ordinance in Japan?
Weren't incendiaries used more over Japan? Also, there was 4 more years of heavy bombing over Europe....Japan really didn't start getting clobbered until 44 or 45, I think. Plus WWI, plus - how many landmass invasions over the years?
But your point is still completely valid.
I suspect there is a combination of several things:
Many tens of thousands (millions ?) of bombs were dropped on the Japanese cities, but only over a limited time frame and in limited (”hah!) areas over only a few limited number of the cities. (Compared to Germany vs the UK for example.)
But with many Japanese cities only hit limited times, even carpet bombing doesn’t spread them out too much.
We didn’t even get airports on the islands and B-52’s to carry them until late in the war. I suspect if you count the number of flights of bombers, there really aren’t many compared to the 6 years of much more indiscriminate air war over Europe
Most of our bombs were fairly small, fairly lightweight incendiary bombs over Japan. They would not bury themselves undereground when they land. So even duds, when exposed to a firestorm from nearby bombs or building, would themselves get cooked off.
A iron bomb could drop and impact and bury itself. Even another close bomb might not set it off.
Our bombs were fairly reliable by that time in the war.
Can't answer your question, but I suspect there are similar stories. Instead I can tell you a related story. In my former employment, we had Geophex (a geophysical exploration company) build us a detector for lost underground storage tanks. under a Small Business Innovative Research project. The instrument is essentially a very low frequency ground penetrating radar. One of the first surveys they conducted with it was to search for unexploded bombs for the Japanese at the former Tachikawa Air Base after we returned the land for the base in the 90s. I did not see the results & do not know if they found anything.
The nature of the physics involved is that it is much easier to find things in relatively open areas than it is in city landscapes with underground utilities, etc.
Geophex also used this instrumentation to do contract work for UNSCO(?) in Iraq in 1997-98 to successfully search for Sadaam's hidden proscribed materials. The system works well in the "pristine" areas there.