[See note: at least lost in English!]
One bit of World War II history I’m interested in, and can only find one reference to on the net.
In May 1945, during a firebombing raid on Tokyo, a POW prison located somewhere in Shibuya Ward caught fire. There were 62 American airmen imprisoned there, along with common criminals and maybe political unfortunates of Tojo’s Tokyo.
What the prison superintendents did was release all the Japanese prisoners and left the Americans locked up to die. They all burned to death.
This was a war crime. So there was a trial, United States v. Kingoro Fukuda. Fukuda, I believe was the superintendent of the prison where the murders occurred.
As I mention, only one site has a reference to this event, at “USMD-14”. (It looks to be a site that sells historical reference materials, which is a bit troubling if you if you consider this particular event a bit. Plus, were these the notes of a government worker, or a press reporter? [UPDATE: I am surprised that item is still for sale (i.e. someone is trying to make $1,000.00 off it) given the nature of the event.])
I’ve walked all around Shibuya Ward in the past few years, but I’ve never seen a marker or anything to indicate where the POW camp/prison had been.
Hoofin 
This might be along the lines of what you are looking for:
http://www.miwachiri.com/tokyo/0301_rikugun.html
The prison was around the area where the ward office/tax office/elementary school now stands.
I seem to recall seeing a stone near there that is meant to calm the spirits associated with it but details of the fire are probably not inscribed anywhere.
There are a couple of other sites around the web that mention this incident. It was the first I had ever heard of it (but this is outside my specific area of interests.)
http://www10.ocn.ne.jp/~kuushuu/rikukei.html
http://www.powresearch.jp/jp/archive/pilot/yokohama.html
http://www.google.co.jp/search?q=%E6%9D%B1%E4%BA%AC%E9%99%B8%E8%BB%8D%E5%88%91%E5%8B%99%E6%89%80&ie=utf-8
Chuckers, I appreciate this. It hadn’t occurred to me to check Japanese-language sources, and so at least the “lost to history” part should refer to English-language history. Sadly, it looks like the details in English are available to the highest bidder, regardless of source.
If there is such a stone here in Shibuya, to the souls that suffered in that specific place, I am sure it would be enough. My feeling was there was nothing.