Japanese Reaction to An Operation Against Southern Kyushu. JIC 191/7, 16 May 1945.

The quotations and images are directly from the document.

“This was the eighth version of a report on anticipated Japanese reaction to an invasion of southern Kyushu. This version is included here because it was the latest iteration prepared prior to the dispatch of the directive discussed in documents 1 and 2 above. This document demonstrates the consistency of the "six combat divisions, two depot divisions" projection for Japanese units on Kyushu Island by 1 November 1945. That estimate, first made more than a year earlier, formed the basis for the figures that would be given to President Truman on 18 June 1945. This projection remained in place right up to the eve of the Potsdam conference in July. The projected Japanese manpower figure for 1 November in this document was 390,000, rather than the 350,000 figure that was used in most of the previous versions of the report. (MacArthur's staff, for its part, estimated the number at 300,000.) The differences did not relate to combat strength but rather to numbers of support forces and naval and air-ground troops.

Two assumptions made about an invasion of Kyushu. The first one was pretty much accomplished, the second happened only after the dropping of the atomic bomb. There is discussion in places about whether or not Russia would have demanded control over part of Japan, like they got control over half of Germany, and that one reason the atomic bomb was used was to end the war before the Russians conquered enough territory to make such a demand.

The document postulates that Japan will not be able to shift more troops to Japan itself from China, since those troops will be busy fighting the Soviets. It also says that, if the U.S. were to invade Kyushu, communications within Japan and between Japan and China will be severed, and that is something the Japanese will fight strongly to stop from happening.

A guess about how many Japanese military will be available to resist a United States invasion.

The document makes the assumption that kamikaze attacks would be very severe, and it's undoubted that they would have been had the U.S. attacked Kyushu. The planes would have been of every variety, probably even including old biplanes. The planes were hidden well, and I doubt that the U.S. bombing would have taken out very many of them, so it's quite likely that U.S. losses in ships and personnel would have been very high.

The document also makes the assumption that virtually everything that the Japanese had left that floated would have been used in kamikaze attacks. This would mainly have been the suicide boats, midget submarines and possibly even some swimmers who would have explosives strapped to their bodies. As far as large ships, the Japanese didn't have many left at all.

An estimation of the ground forces that would have awaited an American invasion.

They are making an assumption that kamikaze usages would eventually decrease, but that is doubtful. The Japanese didn't have much of any good fighter planes or pilots left by late 1945, so pretty much everything they had and everyone they had would have been used in kamikaze attacks.

Another estimation of what Japanese planes would be left. Other reports I have read indicate that there actually were a lot more than that.

An examination of the types of planes that would be left.

More on the probably kamikaze attacks. The problem (for the Japanese) of using the baka bomb, or the manned flying rocket bomb, was that they had to be carried out to a launching area by slow and clumsy bombers. These were easily shot down by U.S. pilots, and not very many baka bombs even had a chance to launch, much less try to hit a target.

The document is making an assumption that virtually all the kamikaze planes available would be used in the Kyushu attack, and that almost nothing at all would have been left to defend the Tokyo plain area if that area had been invaded according to the original plan.

What ships the Japanese Navy had left would have set sail in suicide attacks, but most likely would have been sunk long before they ever would have posed a danger to the assault force.

---

Main Index
Japan main page
Japanese-American Internment Camps index page
Japan and World War II index page