Book Review: Japan’s Secret War: Japan’s Race Against Time to Build Its Own Atomic Bomb (Robert K. Wilcox): WWII

8/12/2001 • World War II Reviews

‘Shortly after World War II had ended,” writes Robert K. Wilcox in the introduction to his reissued book Japan’s Secret War:Japan’s Race Against Time to Build Its Own Atomic Bomb (Marlowe & Co., New York, 1995, $12.95), “Americanintelligence in the Pacific received a shocking report: The Japanese, just prior to their surrender, had developed andsuccessfully test-fired an atomic bomb.”

Could that have happened? Did the Japanese possess a weapon on par with those developed by the U.S. government’sManhattan Project? Wilcox’s book gives convincing evidence that the Japanese were not just bystanders in the race to build anatomic bomb.

In the fall of 1940, the Japanese army concluded that constructing an atomic bomb was indeed feasible. The Institute ofPhysical and Chemical Research, or Rikken as it was known to the United States, was given the contract. A brilliant scientist,Dr. Yoshio Nishina, headed the top-secret project.

At the same time, the Japanese Navy was also diligently working to create its own “superbomb.” The project was dubbedF-Go.

One of the biggest problems facing both branches of the Japanese military was the scarcity of Uranium 235, or U-235. Thisisotope was present in minute amounts in natural uranium and was essential to the fission process. Another major obstacle waselectric power. The home islands of Japan generated very little in the way of electricity. Enter one Jun Noguchi, a Japaneseindustrialist, who offered a solution. A real visionary, Noguchi had built an industrial empire on the Korean peninsula, nearKonan. His factories churned out gunpowder, dynamite, nitroglycerin and magnesium. To achieve the massive amount ofkilowatts needed to run his industries, he had the Fusen and Chosin rivers, tributaries of the Yalu River, dammed. Then heconstructed hydroelectric plants to provide the electricity.

In addition, Noguchi, who was a graduate of Tokyo University with a degree in electrical engineering, was also making heavywater, water composed of heavy isotopes of hydrogen and/or oxygen. Heavy water could be used as a moderator in a nuclearreactor. He also realized the enormous value of the rich uranium fields on the Korean peninsula.

Did the Japanese use Noguchi’s facilities in Korea to manufacture the heavy water they desperately needed to build theiratomic bomb? In Japan’s Secret War, Wilcox states: “Box 2 of the SCAP [World War II Army intelligence files and recordsof occupation] records, Entry 224, mentioned that Noguchi’s company was making heavy water for Arakatsu [Dr. BunsakuArakatsu, head of Japan’s Imperial Navy atomic project at the end of World War II], and reported that Army investigatorshad impounded ‘360 cc’ of heavy water from his cyclotron lab….Former Noguchi employees, Saburo Tashio, director of oneof Noguchi’s labs on the mainland, and Masao Kubota…by the end of 1942, using glass electrolytic equipment, were able to produce 8 liters of 1.2 percent heavy water per month….In January 1944, 3 step constant volume continuous electrolysis equipment…was completed [and] by April 1944…it became possible to produce approximately 50 cc of 90 percent or purer heavy water per month.”

The preceding report concentrates only on the Japanese mainland. What of Noguchi’s plants near Konan? Those buildings,according to Wilcox, “were not subjected to Allied bombing.” Were they producing heavy water at a much faster pace?

Another interesting facet to the Japanese atomic bomb efforts is the apparent coverup by the U.S. government. Why? Whywere Japanese cyclotrons hastily destroyed at the end of the war? The U.S. military had dismissed the idea that the Japanesecould build an atomic bomb. Were American military and government officials embarrassed upon being proved wrong?

Army Major Joseph O’Hearn was one of the officers who oversaw the destruction of the Japanese cyclotrons. On November27, 1945, he wrote, “In the course of my recent mission…a number of factors…convince me that further investigation of thisfield is essential.” He further stated, “There are a number of other devices…existing and in some cases operating in laboratoriesthroughout Japan…related to Atomic Energy research….Certain Japanese scientists have stated quite openly that they arecurrently engaged in Atomic Energy research. They are using equipment…not visited by my party nor to my knowledge by anyother agency.” O’Hearn finally concluded, “My mission uncovered a hidden supply of uranium…but I believe the material…isUranium Oxide, from which Uranium can be readily separated.”

Despite all his research, Wilcox is still unable to prove beyond a doubt that the Japanese did use Konan as a base for makingheavy water and actually test-fired an atomic bomb just after the war’s end in the Sea of Japan. Some of the material that couldshed light on this subject is still classified or, sadly, has been destroyed. If grisly experiments, performed by Japanese doctorson Allied POWs in Manchuria more than half a century ago, could be hidden from the public with the knowledge andassistance of the United States, then why not atomic bomb development?

With all the hoopla surrounding American use of the atomic bomb to end the war against Japan, maybe the question should beturned around to ask if the Japanese would have used an atomic bomb against the United States if they had possessed it?Wilcox, in the epilogue to Japan’s Secret War, states quite emphatically: “The Japanese, in fact, tried to make the bomb [and] got farther than the Germans did. And certainly, as all the documents about their coming Defense of the Homeland indicate, theJapanese would have used the bomb in their defense had they been able.”

Wilcox adds that the Japanese “are not solely the victims of the bomb, as they have been portrayed for so long. They werewilling participants in its use, and only losers in the race to perfect it.”

Even a decade after I first read it, Japan’s Secret War is still spellbinding. It is intriguing and disturbing, and Robert Wilcoxdeserves high praise for his meticulous research. He has traveled the world to interview many of the participants and scouredarchives to unravel a mystery that is as relevant today as it was more than 50 years ago–nuclear proliferation.
Al Hemingway