I-400 Contingency

The I-400 class was Japan's attempt during the Second World War to marry an aircraft carrier with a submarine and unlike many concepts weapons developed during the conflict, actually lived up to expectations. However, the practicality was never fully exploited as Japan surrendered before its maiden voyage, not to mention the completion of the actual fleet itself (only 2 of 18).

Now, this is were I get into the swing of things. After much careful research, including having combed through several eye-witness reports and interviews, three known missions have cropped up for the I-400 class.

The first, code named: "Cherry Blossoms at Night", called for the use of the submarine fleet's arsenal of Seiran planes to wage biological warfare against the United States, more specifically the West Coast. Unit 731, Japan's wartime biological division, headed by Shiro Ishii, chose plague as their weapon of choice. The disease itself would be carried by infected fleas mixed together with flour inside of ceramic containers and dropped within high population centers--possibly even Army bases. Rats would contract the blight from the infested flour after contact with the fleas and hopefully spread the plague among the citizens. The operation was canceled however by General Yoshijiro Umezu, chief of the army general staff, who declared, “Germ warfare against the United States would escalate to war against all humanity.”

The second, (no code name), called for the use of the submarine fleet's arsenal of planes to attack the Panama Canal. Japan's intention was to damage if not destroy the Gaton Locks along with the channel itself in order to delay the United States' shipment of essential war material to the Pacific Theater. If successful, the attack would give Japan much needed breathing room. The submarines were to surface 100 miles off the coast of Ecuador, where they would launch their planes at night. The Seirans, painted to resemble U.S. colors, would fly northeast over Colombia, turn west over the Caribbean, then attack from the north at dawn, torpedoing the Gatun locks. After returning to their launch point, the pilots would ditch their planes and swim to their respective subs. The twist side of this scheme called for the pilots crash into the locks as Kamikaze.

The third, code named: "Operation Hikari", called for the submarine fleet's arsenal of planes to launch a Kamikaze style raid against the US naval anchorage at Ulithi Atoll, the staging ground for the coming invasion of the Home Islands. The two completed submarines (I-400 and I-401) were to rendezvous with the I-13 and I-14 after a brief recon of the target area. More that ten US carriers were moored at the atoll. Together, the submarines would launch their Seiran planes (painted to resemble U.S. colors) and fly at low altitude to avoid radar. In tandem, Kaitan suicide miniature submarines were also to be launched. The entire operation was to take place under a full moon. Afterwards the subs would then sail to Singapore for rearmament and refueling before the staging another attack elsewhere.

Now, Japan at first chose option no.1, later realizing its lethal consequences, then chose option no.2--though not before the fall of Okinawa set in and finally decided on option no.3, to strike back at the US carrier fleet and hopefully delay the inevitable invasion which never came.

What if any of the following operations were actually carried out by Japan? Obviously these suicide missions (no pun intended) would not bring ultimate victory for Japan, but what would be the result if one of said missions actually succeeded (even in highly unlikely)...?
 
Of the three, the best chance might be the last, though I doubt they would be able to do a lot of damage. If they went with the first one, then you may well see Halsey's words come to be true.

Japanese would be a dead language and Japan a wasteland.
 
Of the three, the best chance might be the last, though I doubt they would be able to do a lot of damage. If they went with the first one, then you may well see Halsey's words come to be true.

Japanese would be a dead language and Japan a wasteland.

Except I doubt that the US actually had the means to accomplish that.
 
Thanks for the input everyone, another question however: Would replacing the Seiran float-planes with Yokosuka MXY-7 "Cherry Blossom" suicide aircraft make much of a difference?? Still a losing battle, that much is true, but these flying bombs are near untouchable after the booster rocket is ignited... not mention a larger payload, so would a kamikaze raid based solely around these aircraft achieve better results than the planes actually intended for this mission? Specifically the third option?? I believe on a scale ratio, six MXY-7s could be fit inside a I-400 class sub compared to just three Seiran planes. That's a total of 112 kamikaze if, and this is a BIG if, had the Japanese successfully completed all 18 submarines as the fleet originally called for--the extra four planes belonging to I-13 and I-14, two Type AM class vessels.
 
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That was my thought. Combination of blockade, nukes, and maybe biological warfare like anthrax. Make it so that so surviving Japanese can try to rise up again.

A very DARK and extreme outcome if Japan had used Black Death against mainland US.
 
Thanks for the input everyone, another question however: Would replacing the Seiran float-planes with Yokosuka MXY-7 "Cherry Blossom" suicide aircraft make much of a difference??
Yeah, it'd make a major difference: the MXY-7 had no engines other than the rockets, and fired from altitude could apparently only expect to make about 23 miles. Moreover, I'm not at all confident in a rocket-powered floatplane version, so we'll need a deck-mounted launch stand or something, likely firing in "salvos". Launching from zero airspeed and sea level means it's possible that this operation would need to be conducted within sight of land, never mind under the regular patrols of shore-based aircraft and shore traffic. I think you're better off with more conventional aircraft that at least can manage a range ten times that where at least the subs have a chance of returning home for another mission.
 

TFSmith121

Banned
None of these missions are likely to be even remotely successful

The I-400 class was Japan's attempt during the Second World War to marry an aircraft carrier with a submarine and unlike many concepts weapons developed during the conflict, actually lived up to expectations. However, the practicality was never fully exploited as Japan surrendered before its maiden voyage, not to mention the completion of the actual fleet itself (only 2 of 18).

- snip -

What if any of the following operations were actually carried out by Japan? Obviously these suicide missions (no pun intended) would not bring ultimate victory for Japan, but what would be the result if one of said missions actually succeeded (even in highly unlikely)...?

None of these missions are likely to be even remotely successful in 1945, considering the US intelligence edge over Japan and the operational edge in terms of ASW, air defense, etc.

See USS England's cruise for an example of the ASW mastery the USN had by 1944, for example...

From Combined Fleet:

Japan started the war with 63 ocean-going submarines (i.e., not including midgets), and completed 111 during the war, for a total of 174. However, three-quarters of these (128 boats) were lost during the conflict, a proportion of loss similar that experienced by Germany's U-Boats. Most of the surviving boats were either dedicated to training roles or were recently completed and never saw combat. Of those which saw significant combat, the toll was very grim indeed. For example, of the 30 submarines that supported the Pearl Harbor attack, none survived the war.

Compared to German submarines, Japan's huge boats were relatively easy to sight visually and with radar, slow to dive, hard to maneuver underwater, easy to track on sonar, and easy to hit. Japanese hulls were also not as strong as those of German boats, and therefore could not dive as deeply nor survive such rough treatment. Also, they lacked radar until the first sets were installed in June 1944, and never had sets as good as the Allies possessed.

Compounding these deficiencies, Japan was at war with the United States and the United Kingdom, two nations embroiled in a vast conflict with hundreds of U-Boats in the Atlantic, and hence two nations which poured lavish resources into anti-submarine warfare (ASW) research and development. As an example of the fruits of this research, in June 1944 the US Navy sank the I-52 by using code-breaking to discover her schedule, finding her at night with radar-equipped carrier-based aircraft, tracking her underwater with sonobuoys dropped by those aircraft, and sinking her with acoustic homing torpedoes dropped by the same aircraft.

The Japanese could achieve none of these technological feats at that time.

And the first special mission is a) rather unlikely to work in any even remotely successful manner, and b) if it is discovered, gives the US full justification for weapons free (including both US chem-bio, nuclear, and HE/incendiary bombing) ofr Japan, including Kyoto and any other city that hasn't already been devastated.

There's one wonder weapon that made a difference in WW II; none of the Axis powers were anywhere close to it.

Best,
 
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