Land of the rising mushroom cloud?

I was reading another message board that I frequent often, and a rather heated political debate got started. Somewhere along the way it started branching out into a discussion of the history of nuclear deployment, and someone made the following comment:

“A small group of historians believe that the Japanese actually test-detonated one in a submarine in the South Pacific in late 1944.”

You can read the rest of the post here:

Two questions come to mind:
What historians believe this? And, is this theory plausible in the least?

I found this link which debunks the whole concept:

I also found a citation of the apparent origin of this story:

D. Shapely, “Nuclear Weapons History: Japan’s Wartime Bomb Project Revealed,” Science, 199, 152 157 (January 13, 1978), p. 153. The first reported
military-sponsored study concerning atomic energy was initiated in April 1940 by the Japanese Army’s Aviation Technology Research Institute (R. Rhodes, The Making
of the Atomic Bomb, Simon and Schuster, N.Y., 1986, p. 327). Army funds were provided to Y. Nishina’s Riken Laboratory, Tokyo, in September 1940, for atomic bomb
research. The first “committee” was the “Physics Colloquium” established by the Riken Laboratory for the Japanese Navy. This colloquium held ten meetings between
December 1942 and March 1943.

Since “Science” is peer reviewed, I suspect it is an authoritative report. The citation indicates that scientists met 10 times to discuss making an atomic bomb. And that is all they did.

When the Germans abandoned their bomb program, they continued to develop technology called “radioactive salting” where they intended to spread radioactive elements over enemy territory. The Japanese loved the idea, as they were already experimenting with aerial spraying of biological weapons. Presumably they intended to use radioactive salting against the US with the balloon bombs they used late in the war.

No, sorry, there is no evidence that the Japanese had any serious bomb project. There is evidence that scientists met and discussed the concept, but they never had funding to actually do anything about it, it was all theoretical discussion.

I once read a crackpot book that claimed to have translated some alchemical documents from the 14th century described the refining of uranium ore. The documents warned against concentrating too much of it, as an explosion would occur. I actually give this report MORE credence than the Japanese bomb story.

I first read about a rumor like this in a book called Japan’s Secret War. The bomb test was supposed to have taken place on an island off the coast of Korea. It was an annoying book because early on the author seems to imply that it really happened. It’s not until you get to the end of the book that you realize his conclusion is that it almost certainly didn’t happen. The book is around here somewhere; I’ll see if I can find it. IIRC, his conclusion was that Japan was farther along in developing the bomb than either the U.S. or Japanese governments are willing to admit, but not very close to having a workable device.

Now I see that Chas.E.'s link refers to Japan’s Secret War. It seems to me that a big part of the misunderstanding is that it requires a careful reading of the whole book to realize that Wilcox’s conclusion is that there was no A-bomb test. The fault is Wilcox’s.