A World at Arms (109 page)

In the final stages of the Pacific War, the intelligence gained by the Americans from reading Japanese codes played a major part.
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By that time, the heavy bombardment of Japan forced the Japanese to utilize the radio not only for messages to ships at sea but for all manner of other messages of which many might otherwise have been sent by secure routes. The sending out of the super-battleship
Yamato,
for example, was thus revealed to the Americans. Similarly, as reviewed in
Chapter 16
, the Japanese plan “Damocles” for a suicide airborne landing attempt on the Marianas was precluded, after its details became known, by the last great massed raids in early August, 1945, on the bases from which it was to have been launched. And the atomic bombs would be dropped on Japan when intercepts revealed to the Americans that the Japanese government had considered but rejected the advice of some of its diplomats that she surrender. Rather than save these weapons for the support of the invasion of the home islands, the Americans used them in an effort to get the Japanese government to reconsider its decision to fight on.

Signals intelligence, which played so large a role in the Allied campaigns of the Pacific War, was also of great significance in the war against Germany and Italy. In that theater, the lead was taken by the British who first had their real practice on German and Italian machine cyphers in 1937 during the Spanish civil war.
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The key steps toward the breaking of the German machine cyphers came from Polish pre-war intelligence, which was assisted by German cypher material sold to French intelligence and provided by the latter to Warsaw.
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In England (and earlier in France), the rather unproductive effort was thereafter successfully pushed forward, frequently helped by the errors made by German operators–especially in the German air force–in the use of the different enigma machine cyphers.
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Very important materials assisting the British in the breaking of German codes were seized from German submarines and weather and supply ships; similarly breaks into Italian codes were facilitated by material taken from Italian submarines and captured in the North African desert war.
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German diplomatic material provided to the ass by Hans Bernd Gisevius and Fritz Kolbe, who belonged to the internal opposition
to Hitler, was used to further work on codes in the fall of 1943;
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by that time the British cryptographers had also broken into the German “secret writing machine” (the
Geheimschreiber)
, a different encoding system from the enigma.
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The impact of these cryptographic successes on the war is still being assessed because, as in the earlier American official accounts, all reference to “special intelligence” had been ordered omitted from the published volumes of the British official history.
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There can be no doubt that the Allies were greatly assisted by the ability to read at least some Axis codes, beginning in 1940.
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Repeated reference to the use of information from what was called “ultra” is made throughout this book. By way of summary, the following may help clarify a difficult problem. During the campaign in the West in 1940, as during the German Balkan campaign in the spring of 1941, the British were simply not in a position to take advantage of what they learned.
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On the other hand, both in the Battle of Britain and in the Battle of the Atlantic, ultra information was of great significance. In the former it aided the proper use of the Royal Air Force, in the latter it helped the steering of convoys around submarines and occasionally in the destruction of the latter. As explained in
Chapter 7
, the use of ultra played an enormous role in the war at sea until 1945 with ever greater advantage to the Allies from the end of 1942 on.

In the Mediterranean and North Africa, code-breaking was important in the naval war, including the Battle of Matapan on March 28, 1941,
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the sinking of a high proportion of the Italian supply ships to Libya and later to Tunisia,
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and also to Montgomery’s campaign against Rommel from the fall of 1942 on. At first the Allied landings on Sicily, in Italy, and later in France were affected by the ability of the Axis to use secure land communication systems; but once battle was joined, the Axis used radio extensively and this opened up their messages to interception and decoding. Of the more spectacular examples, one could cite the Allied knowledge of the planned German offensive at Mortain in August, 1944. Considerable reexamination of many details of the operations in Italy and France and the Low Countries will still be needed before a final judgement can be made, but there can be no doubt that time and again ultra information played an important role in the deliberations of Allied commanders.

A further major advantage of ultra for the Western Allies was the information it provided them about the fighting on the Eastern Front. In view of the reluctance of the Soviet Union to share with its allies details about its own or the Germans’ operations, the decrypting of German radio traffic was the most important single source the British and Americans had on that portion of the war. This is a subject which
still awaits investigation in detail, but ultra at least provided the Western Allies with some idea of what was transpiring on the front where such a large part of the fighting was taking place.

From time to time ultra also provided clues to Axis subterfuges. Thus when in 1942 the Italians decided to conceal gasoline supplies for North Africa on hospital ships, the British learned of this ruse from decyphered messages and sank some of the ships.
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Similarly, decodes of Japanese radio traffic uncovered their attempt in 1945 to use a hospital ship as a troop transport.
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Given the significance of signals intelligence to the Western Allies, it is not surprising that both Churchill and Roosevelt followed it carefully. Churchill had a positive fascination for the subject and constantly insisted on being supplied with it.
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Roosevelt appears to have paid careful attention to it as well,
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and was absolutely insistent on maintaining civilian control as well as army and navy involvement.
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It must always be remembered, however, that there were constant limitations on the usefulness of signals intelligence. The factor of delay has already been mentioned. The repeated changes in machine settings, the need to provide cover-stories, and the problem of selecting out of the vast quantities of intercepts those of most immediate relevance for decrypting imposed limits on even the most efficient operation at Bletchley Park, the main British center, and Arlington Hall, the American equivalent.
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On the other hand, a long-term benefit of all the effort was the development of an entirely new computation device–the computer. There was a truly rapid evolution from the Polish Zygalski sheets and cyclometers to the huge British and American computers of 1944–45. Though using tubes where post-war models would utilize chips, the “Colossi” of World War II were indubitably the ancestors of the modern PC.

While all this was in progress, the Germans, like the Japanese, refused to believe that their wonderful machine codes could be broken. Each time they examined the possibility, each time there were hints, they preferred to retain faith in their inventions.
^f
Repeated investigations by the navy, which was especially affected by the possibility of its messages to and from the submarines at sea being read, invariably concluded that German communications were secure. At the international conference on signals intelligence held in Germany in the fall of 1978, a number of participants who had played active roles in the events described still found it hard to believe that their machine codes had indeed been read at least in part by the Allies.
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Those who are directly involved in the
making of codes and of secure telephone scramblers and related devices are always the last to believe that others–who are by definition not as brilliant as they are–could possibly have found a way to break into their wonderful devices.
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A procedure often used in warfare in the past and increasingly tied to signals intelligence in World War II was that of deception, that is, deliberately misleading the enemy about one’s intention in order to achieve or at least assist surprise and success at the actual point of attack. Certainly the successful deception operation of the Western Allies, in pursuading the Germans that the major landing was still to come in the Pas de Calais area, depended heavily not only on deceiving the Germans about real Allied strength and intentions but on the ability to monitor the success of this effort by reading German messages to their own headquarters and to the German agents, real and imagined, in England, who were in fact all under British contro1.
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Whether or not the simultaneous Soviet success in deceiving the Germans about the planned location of their 1944 summer offensive also included reliance on reading German codes is not known.

Deception efforts in Europe not only accompanied ground operations but were often attempted in air raids, usually to disguise the actual objective of a bombing attack or the direction from which it was coming. These attempts frequently failed, as in the first big American raid on the Ploesti oil fields and refineries on August 1, 1943; at times they succeeded in diverting the defenders, as in the British raid on the German experimental station for missiles and pilodess planes at Peenemünde on August 17, 1943.
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Perhaps the most serious Allied deception failure in Europe were operations “Starkey” and “Cockade,” two hopelessly bungled efforts in 1943 to make the Germans believe that there would be an Allied invasion of Western Europe that year, in the hope of diverting German forces from the Eastern Front.
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At times, even a successful deception could have reverse implications elsewhere. The total failure of the British attempt to seize islands in the Aegean in the fall of 1943 can be attributed in part to the stupidity of the Italians in the area, in part to the incompetence of the British command, and in part to the refusal of the Americans (for strategic reasons) to support the operation, but a contributing factor was the success of the Allied deception operation “Mincemeat,” the ploy with “The Man Who Never Was,” in diverting German reinforcements from Sicily to other locations, including the Aegean.
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In the Pacific portion of the war, deception was, of course, used at times by both sides. An example of how code-breaking can make a major
difference in this regard can be seen in the success of the Americans in making the Japanese believe before the Battle of Midway that several of their carriers were elsewhere,
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and the failure of the Japanese effort to fool the Americans by a diversionary operation against Alaska and the Aleutians. Whether or not the “Wedlock” operation, an American deception designed to make the Japanese reinforce the Kurile Islands in 1944 when their real target was the Marianas, succeeded is likely to remain contentious.
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One of the major weapons innovations of World War I, introduced by the Germans and imitated by the Allies, had been poison gas. The years between the wars had seen both efforts at international agreement to ban poison gas and continued production and experimentation with it. Aside from experimentation carried on in the Soviet Union with the approval of the latter, the Germans simply kept up with other powers in the 1920S and 1930s until major breakthroughs led to the development of nerve gases, beginning in 1936 and their production on an increasing scale during World War II.
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Tested on prisoners of war and on concentration camp inmates, the nerve gases, Tabun, Sarin, and Somar, also claimed some victims as a result of accidents and errors in the production process but were never employed at the front.

The decision by Hitler not to use the nerve gases, which was made in or about May of 1943, was made on the basis of several considerations. The one which we now know to have been false was the belief that the Allies also had nerve gases.
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Of great importance was the evident reality of great Allied air strength obviously capable of making good on the repeated public announcements that poison gas would be used in retaliation for any German use of it, either on the Eastern Front or anywhere else.
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An equally significant restraint on the Germans was their lack of gas masks of any sort for much of the country’s civilian population.
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The British built up substantial stocks of phosgene and mustard gas, both widely used in World War I. They had been willing to use this weapon in 1940 if the Germans succeeded in establishing a substantial beachhead in an invasion, a point discussed in
Chapter 3
. In 1944, Churchill would urge the use of gas either against the sites from which the V-1s and V-2s were about to be launched or elsewhere in retaliation for these new forms of indiscriminate bombardment, but contrary advice from his own military Chiefs of Staff and the objections of the Americans prevented any such employment of poison gas.
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The requests of the Soviet Union to its allies to threaten retaliation
in kind to any German use of poison gas on the Eastern Front were presumably based on a real concern. The Soviet Union had, it would appear, made some preparations of its own in this field but evidently intended to use gas only in retaliation. The opening of Soviet archives may bring new information on the subject, especially since the major German facility for the production of nerve gas, IG Farben’s plant at Dyhernfurth, fell into Soviet hands undamaged in 1945.

The United States built up a very large stock of the gases used in World War I for employment in case either the Germans or the Japanese turned to this weapon.
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Although the possibility of the use of gas in combat was considered in the preliminary discussions of the invasion of Iwo Jima and the Japanese home islands in 1945, such projects were always vetoed by the President or dropped by the military on their own.
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The shipment of chemical warfare shells to the theaters of war for use if retaliatory employment proved necessary led to the greatest loss of life in a gas accident during the war. A German air force bombing raid on ships in the harbor of Bari in Italy on December 2, 1943, led to the destruction of one ship (among seventeen) which carried 100 tons of mustard gas in bombs; over a thousand Allied personnel and Italian civilians being killed as a result.
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