Eavesdropping On The Rising Sun

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Convinced that their encryption was immune to compromise, the Japanese continued to use it throughout the war, giving us a critical window into their high councils. Coupled with our Navy's success in breaking the systems used by the Japanese fleet, our work with Purple provided us with a powerful push toward victory and guaranteed a well-funded future for signal intelligence.

I was only involved with Purple for a short time and was then moved to a quieter front, working on "back traffic" in a shipping code that had expired. It was still useful for accumulating strategic data on Japan's logistical problems and also for identifying sea routes that became hunting grounds for our submarines, but I wanted to get a little closer to an actual scene of war. I managed to finagle a posting to New Delhi in the China-Burma-India (CBI) theater in August 1943.

By the time another translator and I reached New Delhi, after a long and slow passage over the Pacific, another six months had passed. Hardly had we unpacked our barracks bags than news arrived that our soldiers had captured a main Japanese army code- book. The timing was perfect in the CBI. The Japanese had launched an invasion of India, hoping to trigger a widespread revolt against the already expiring British rule. At the same time, a joint British, American, and Chinese task force began a campaign to retake northern Burma from its Japanese conquerors. Behind their advancing front followed thousands of U.S. Engineer Corps troops. They built a remarkable highway known then as the Ledo Road, which twisted over unmapped mountains, across monsoon-swollen rivers, and through dense jungle, providing a critical land connection between India and China.

The first ripe fruit of the code- hook's capture appeared in early March 1944 in the form of a midnight announcement from the Japanese high command in Burma that their 15th Division had started across the Chindwin River along the border between India and Burma. Someone rushed the information over to British headquarters. From then on, most traffic relating to the invasion was diverted to the British cryptanalytic offices, but a flood of information from Burma came our way.

The messages came as fast as our own decoders could process them, and occasionally too fast for the Japanese code clerks themselves. We knew this because we'd sometimes intercept a "service message," or request that a sender repeat a garbled "key." Only my buddy and fellow translator Guy Henle and I were there as translators, because Arlington Hall had anticipated a far more limited CBI operation. For a couple of weeks the two of us worked more or less around the clock, pulling both day and evening duty. We alternated evening shifts so we could grab a little sleep. A third translator, our former classmate Frank Tenny, was rushed out to us by air, and eventually others followed. But for a brief spell in the fierce humidity of the New Delhi spring and summer of 1944, I was absorbed completely and happily in important work. Amid the routine administrative messages devoted to changes of assignment or reorganizations of command structures, there were reports of troop strength and movement. The latter were hurried across the street to G-2 (intelligence) and relayed to Gen. "Vinegar Joe" Stilwell, commander of the frontline units. After a visit to headquarters, our section chief came in beaming one morning to announce that the top brass had ordered us all to "keep it coming."

One night Guy and I spotted a message that kept repeating the non- Japanese word "gu-ra-i-da." We quickly figured out that it meant "glider," the Japanese substituting "r" in place of "1," which doesn't exist in their language. As we translated more of the message, we started to tingle with excitement: it delineated exactly where a small armada of troop- and equipment-carrying gliders had landed inside Japanese-controlled territory—and specified how they were initiating defensive responses. The message also spelled out the name of the American commander of the operation as "fu-ri-pu ka-ku-ran." Both of us repeated fu-ri-pu quickly aloud and came up with "Flip."

"My God," I yelled. "Flip? Flip Corkin!" That was a character in Terry and the Pirates , a favorite comic strip of mine. Corkin was a wise cracking, savvy, and heroic fighter pilot, modeled on Philip Cochrane, a real-life friend and college classmate of the strip's author, Milton Caniff. By 1944 Cochrane—"ka¬ku-ran"—had become a colonel in the Army Air Forces. So the message was the hottest of hot stuff—the Japanese had enough information to prepare a counterstrike against an ongoing airborne operation; because their intelligence had gotten hold of the name of its commander, they might have even more damaging knowledge. We hustled over to the night duty officer, who woke up our section chief He immediately took the translated message to the upper echelons of command.

Our small unit had picked up the first Japanese reaction to Operation Broadway, one of the war's most daring undertakings, in which the Allies built a base far behind Japanese lines in Burma. Gliders towed by paratroop-carrying transport planes had landed engineers, earth-moving equipment, and covering infantrymen in a tiny cleared zone in the jungle. They laid down an airstrip large enough to supply and defend a base of support For British guerrilla units. Known as "Chindits," these special forces inflicted enough damage on Japanese transport and communications to fatally sap enemy fighting strength in Burma.