Medical scientists, on Ishii’s orders, drained the blood from POW’s bodies, replacing it with horse and monkey blood (in an effort to create “artificial” bloods). Japanese soldiers tied POWs to stakes and exploded germ bombs overhead, while timing their deaths with stopwatches. Medical examiners even dissected live POWs!

No abomination was indecent enough to halt the heightening fervor of experimentation. Prisoners-of-war and the surrounding population were deemed expendable by the Japanese who believed their loss wouldn’t be missed. The use of human guinea pigs was widely known within Japan’s medical community, but prompted no ethical outrage.

Ishii Goes Into Hiding After the War

When the war ended in August 1945, Ishii made arrangements to flee to Japan and to appoint Dr. Ryoichi Naito as liaison to the United States. He subsequently delivered a 12-page, handwritten, chain-of-command accounting of Operation BOEKI KYUSUIBU (Water Purification Unit) that admitted some of its practices and led directly to Japanese Emperor Hirohito.

As Pingfan was being dismantled and destroyed (so large was the production plant in the heyday of Unit 731, it had the potential for creating sufficient bacteria to kill the world’s population several times over), Ishii went into hiding with his specimens and research data.

Immunity For Program Data Suggested

Dr. Ryoichi Naito then contacted Lt. Col. Murray Sanders, a biological warfare specialist on the U.S. Scientific Intelligence Survey. Sanders recommended to Gen. Douglas MacArthur that, in exchange for their data, the Japanese researchers be granted full immunity from prosecution for war crimes.

Sanders wasn’t the lone voice for support. Other U.S. scientists supported his recommendation without regard to moral qualms or ethics. Some even suggested lying so as to prevent this information from falling into the wrong hands.

Meanwhile, China and the Soviet Union hounded the United States with requests to interrogate Ishii for war crimes. But on May 6, 1947, MacArthur sent this top secret cable to the U.S. War Department: “Experiments on humans were known. Confirmed by Ishii. If guaranteed immunity from war crimes, he can describe program in detail.”

Biological Data Pursued Over Prosecution

Three months later, on August 1, a combined State, War, Navy, and Coordinating Committee for the Far East report stated: “The value to the U.S. of Japanese biological warfare data is of such importance to ‘national security’ as to far outweigh the value accruing for ‘war crimes’ prosecution.”

To consummate the “deal,” the United States paid the equivalent of 250,000 yen for the excavation of eight thousand slides of human tissues and 60 pages of reports that Ishii had buried in mountainsides and hidden in temples. Returning American POWs were ordered not to discuss their ordeal with anyone.

And what of Ishii? He was a welcome guest at Camp Detrick, Md., where he lectured U.S. scientists and military personnel on the results of his human experimentations. He died in Japan of throat cancer in 1956.

All told, Unit 731 killed 12,000 White Russians, Chinese, Manchurians, and Mongolians in gruesome experiments. Another 200,000 Chinese perished in germ warfare “field experiments,” according to Sheldon Harris in Death Factories.

This article first appeared on the Warfare History Network.

Image: Wikimedia Commons.