Robert Wilcox’s Third Edition of Japan’s Secret War has just been released and it is a blockbuster. The new edition explains how Japan’s World War II effort to build an atomic bomb formed the foundation for today’s North Korean nuclear program. Wilcox might have added that Japan was also a vital resource for the Soviet Union who took control over Korea down to the 38th parallel in 1945.

The Russians knew exactly what they were looking for, and they got it. Korea, until the end of the war annexed by Japan since 1910 (a deal blessed by President Theodore Roosevelt) was the most important part of Japan’s atomic bomb program. The allies, especially the United States, did not know that. The Russians did.

While it can’t be proven today, I believe that the Russian spy in Tokyo, Richard Sorge, hanged by the Japanese in November 1944, provided vital information on Japan’s atomic bomb program to his NKVD bosses. No doubt it was his information that gave Lavrentiy Beria, the NKVD head, the scientific information he needed to pursue the bomb, and Stalin put him in charge of the project (showing clearly that the Soviets depended on the flow of intelligence for their A-bomb effort).  Stalin also took advantage of Truman’s invitation to intervene in Mongolia and Korea almost at the end of the war.  As Wilcox points out, the toughest fighting was when the Russians took control of the Konan (Hungnam) area where Japan’s nuclear work was centered in Korea.

Japan had (at least) two major atomic bomb programs, one run by the Japanese army and headed by Yoshio Nishina of Japan’s Institute of Physical and Chemical Research (RIKEN) and the other run by Bonsaku Arakatsu who ran the navy’s F-Go atomic bomb project. Both men were top physicists, and Nishina had strong connections to Albert Einstein, Ernest Lawrence at the University of California and Niels Bohr (whom Nishina again visited after the end of World War II).

It was the navy project that used Korea for uranium enrichment and thorium processing. North Korea is rich in monazite, an excellent source for thorium. Thorium in a nuclear reactor can be changed to the element protactinium and then through chemical processing to uranium (U-233). (This appears to be what the Germans were doing, too. As Paul Frame points out, Auer Gesselshaft, “a German chemical company involved in securing and processing uranium,” had taken over the French thorium company Terres-Rares during the Nazi occupation.”

The US only learned about the Korean thorium in 1946, and by that time Konan was under Russian control. But there were strong enough indications about the Konan area for the US Air Force to send a camera-equipped B-29 named Hog Wild to fly over Konan on August 29, 1945 – 14 days after Japan surrendered. Russian Yak fighters shot it down and it crash-landed.

In 1950 at the time of the Korea War, the US Air Force bombed Konan and destroyed the thorium processing facilities there.

As Wilcox explains, much of the most critical bomb-making in Korea was done in caves, just as North Korea is doing today (perhaps using some of the same caves). The US had no ability to destroy the caves, and in the fighting during the Korean War, some of the toughest battles took place around the Chosin Reservoir. There UN forces were thrown back and defeated and were finally rescued at the port of Konan (Hungnam) between December 15 and 24, 1950.

Much of the evidence about Japan’s atomic bomb program is still classified, and those Japanese scientists and military men Wilcox interviewed were far from candid in their accounts of Japan’s atomic bomb program.

If the US ever declassifies critical documents, the history of atomic bomb development, the looming crisis that was headed off by the atomic bombing of Hiroshima and Nagasaki, will finally be revealed.

Wilcox’s new third edition should be required reading for policymakers today.

Robert K. Wilcox: Japan’s Secret War: Third edition Revised and Updated (New York: Permuted Press, 2019)