Discovered: forgotten Japanese midget submarine base built for WW2 suicide missions
- The submarines would have been tasked with attacking the Allied invasion fleet that was expected to try to land forces on Kyushu
- Nearly all military sites were identified and razed by the Allied Occupation forces after Japan’s surrender in 1945
A military analyst described the discovery of the base, more than 75 years after Japan’s surrender, as “remarkable” and potentially a source of new information about the actions of the Japanese forces in the final stages of the war.
Some details of the base survived in Imperial Japanese Navy records but it had been largely forgotten by local residents after it was abandoned. Its erasure from local history has been helped by the small island having no residents and being rarely visited, although that changed when six members of the Sengoshi Kaigi Matsue historical group followed a vague report and visited the island for the first time in October, the Asahi newspaper reported.
Subsequent research indicated the base was designed to serve as a training facility for the crews of midget submarines that would be tasked with attacking the Allied invasion fleet that was expected to try to land forces on Kyushu. That mission was code-named Operation Olympic and was the first part of the broader Operation Downfall, which would bring about Japan’s final surrender.
Operation Olympic was scheduled to start in November 1945 but was cancelled when the US dropped atomic bombs on Hiroshima and Nagasaki in August that year. Japan announced its surrender on August 15 and its formal surrender was signed on September 2.
It is believed work on the base began in June 1945 as part of the last-ditch effort to protect Japan from invasion but the entire facility was never completed. It is unknown how many crew were trained or how many submarines were deployed.
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“To find something like this is extremely unusual in Japan and I have not heard of anything of a similar scale being found anywhere else here,” said Garren Mulloy, a professor of international relations at Japan’s Daito Bunka University and an authority on defence issues.
Mulloy said the discovery of the base was remarkable for a number of reasons, not least because it does not appear to have been identified and razed by the Allied Occupation forces after Japan’s surrender.
“GHQ was very thorough about these sorts of sites after the war because they were wary that the Japanese would try to squirrel away military equipment for use in the future, although we now know that did not happen,” he said.
“My guess would be that the Japanese gave up on this facility before the end of the war and they either forgot to mention it to the occupation authorities or did not think it was of any significance.”
Official records of the site are also likely to have been destroyed in the widespread burning of documents that took place across Japan between the announcement of the surrender and the formal signing, he said.
The base was likely forgotten as residents died or moved away over the following decades, while the island was never redeveloped, he said.
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It is, however, just the latest rediscovery of relics and remnants of the war across Japan. An island off Hiroshima in the Inland Sea still has the remains of buildings that were a top-secret facility for the manufacture of chemical and biological weapons used in China, while parts of a torpedo testing facility survive in Kagoshima, where pilots trained for the attack on the US fleet at anchor in Pearl Harbour in December 1941.
Unexploded bombs are frequently found on building sites across the country, along with smaller calibre ordinance in Okinawa, where there was fierce ground fighting in the latter stages of the conflict. In 2018, more than 1,400 guns and 1,200 swords were found buried beneath the playground of a school in western Tokyo. Schools often served as training facilities during the war and it is likely the weapons were simply buried after the surrender.
