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| ISBN-13: | 9781612515250 |
|---|---|
| Publisher: | Naval Institute Press |
| Publication date: | 03/01/2009 |
| Sold by: | Barnes & Noble |
| Format: | eBook |
| Pages: | 296 |
| File size: | 3 MB |
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Chapter One
Genesis:
German-Japanese
Cooperation
Japanese foreign minister Mamoru Shigemitsu's 1943 comment to his German counterpart, Joachim von Ribbentrop, subtly acknowledged a fact of which both men were already aware. Of the Axis powers, Germany was clearly the strongest industrially and economically, resulting in expectations that Germany would extend aid to its Japanese and Italian partners in those developmental areas in which they were deficient. As early as 1937, then-Captain Kojima Hideo, the Japanese naval attaché in Berlin, recognized the necessity of German aid for the Japanese war effort and proposed a protocol for the exchange of tactical and technical information and materials between the Japanese and German navies. However, primarily because of German fears that such an exchange would be one-sided, a definitive cooperative agreement was delayed until 1940.
On 27 September 1940 Germany, Italy, and Japan signed the Tripartite Pact, thereby committing themselves to mutual economic, political, and military support in the establishment of Axis hegemony throughout Europe and Asia. To ensure the solidarity of the alliance, Article 3 of the treaty called upon the allies to recognize each other's spheres of influence within the new order, by directing the signatories to "cooperate [in] their efforts" and to "assist one another ... when one of the three Contracting Parties is attacked by a power not involved in the European war or in the Sino-Japanese Conflict." Another thinly veiled reference to the potential involvement of the United Statesappeared in Article 4. Cognizant of the potential of American industrial prowess, Japan insisted upon a provision that called for military collaboration, resulting in the formation of a Joint Technical Commission that was to assemble "without delay."
The extent of Japanese and German concern over military and technical cooperation was evident throughout the various amendments to the treaty. In a notation marked "Strictly Confidential," the German representative, a General Ott, pledged that Germany would "use her industrial strength and other technical and material resources as far as possible in favor of Japan." In return, Tokyo promised to return Germany's former Pacific possessions then under Japanese mandate. In a supplementary protocol on military aid, the allies agreed to "exchange ... without delay all useful inventions and devices of war and to supply one another with war equipments, such as aeroplanes, tanks, guns, explosives ... together with technical skill and men should they be required."
Despite the enthusiasm that surrounded the signing of the Tripartite Pact, the Axis spirit of solidarity soon soured, as both Germany and Japan grew frustrated by a perceived lack of reciprocity. Former Reich war minister General Field Marshal Werner von Blomberg outlined the seriousness of the situation by complaining that "our relations with our ally Japan [are] more grotesque than anything in previous history," and he reminded his colleagues that Japan was "a country to which we have no spiritual bonds except some peculiar ss interpretation of the Bushido code of ideology." Furthermore, the Oberkommando der Kriegsmarine (OKM), or German Naval High Command, charged that Japan's offer of anchorages and ports for German auxiliary cruisers in the Far East "in no way justifies the prevailing view of a one-sided assistance on the part of Japan.... It is therefore necessary to challenge any such Japanese notions ... and to emphasize the absolute reciprocity provided for under the Pact." To guard against the assumed inequity, the OKM placed certain sensitive items that might be requested by the Japanese under the discretion of the Naval War Staff, who would subject such items as sonar and radar to strict guidelines. In addition, the staff would determine which new equipment, then under development, would be available for Japanese assessment.
In December 1940 the Japanese, alarmed by Germany's reluctance, dispatched a joint army and navy mission to Berlin to present their material concerns. In early February 1941 this joint committee, headed by Gen. Yamashita Tomoyuki (the future "Tiger of Malaya") and Adm. Nomura Naokuni, presented a "wish list" of Japanese requests, to which both the Kriegsmarine (German Navy) and German business interests were vehemently opposed; the navy demanded that any material aid afforded Japan must be used directly against the British in Asia, while German businessmen feared that their products would be turned against them by the Japanese in the postwar years. However, the doubts of naval and business leaders were not shared by either the Wehrmacht (German Army) or, more important, Adolf Hitler.
On 5 March 1941 Hitler issued Basic Order Number 24, which addressed the deteriorating relationship between Germany and Japan. The key provision of the order was item number 2, which stated that Japan's military potential must be strengthened "with all means available," particularly in technical matters. Hitler further directed all branches of the German military to comply with Japanese requests in a "comprehensive and generous manner" and stated that "while reciprocity is desirable, it should not stand in the way of negotiations." To accommodate the Führer's wishes, the Military-Economic Section of the Wehrmacht Armaments Office was appointed the responsible agency for the direction of German aid to Japan.
Despite the expressed wishes of Hitler, the OKM sought to stall German compliance with Japanese requests. The OKM pointed out to Ambassador Karl Ritter that since the wish list had been issued before Japan's official entry into the war, it would have to be reviewed and possibly amended in light of the changing logistics of transport. In addition, the OKM argued that Russia would refuse any request to allow traverse of the Trans-Siberian Railroad for the delivery of these items. As a result, no simple route of conveyance existed. It was determined that although there was no "secure means of transporting goods in quantity," it would be possible to transport "a few models with the relevant technical drawings and plans" needed to facilitate Japanese production of German equipment.
Notwithstanding internal resistance to the cooperation provisions of the pact, Germany nevertheless intended to honor the treaty and subsequently began sending blockade-running vessels to the Far East from Bordeaux during the fall of 1941. However, the Japanese were generally disappointed with the cargo. Whereas the original wish list reflected Japan's potential defensive weaknesses in its requests for large-caliber artillery, radar, tanks, submarine and aircraft components and models, and precision instruments and machine parts, the cargo consisted mainly of industrial chemicals and machinery. And however disappointed the Japanese were with the cargo, the Germans were even more disappointed with what they received in return. A top-secret OKM memorandum dated 27 May 1941 concurred: "The Japanese are unable to pluck up the courage to do anything in our interest that involves the slightest risk for them." On 29 December 1941 the chief of the Special Staff for Economic Warfare issued a memorandum to the German Foreign Affairs legation, which stated that "what has been received from the Japanese ... is very limited.... More must be demanded [particularly] the exchange of all war experiences in [Japan's] previous naval, land, and air operations." The Japanese reminded their ally that, in addition to supplies, they had provided refueling and rest stations for German blockade-runners, reciprocal actions that in their opinion placed Germany in Japan's debt. The OKM was not impressed, however, replying that "the material and technical support that Germany has received in the provision of anchorages and supplies" did not represent adequate compliance with the pact.
Although the Führer expressed his desire to allow the Japanese to study German munitions factories and research facilities, resistance to handing the Japanese carte-blanche access was substantial. During the spring of 1941, representatives of the Japanese military mission were offered the services of specialists in the "strategic, tactical, and technical spheres" of Germany's military and—thanks to what the Germans called "the maximum degree of openness on our part"—were guests at numerous briefings on the German war experience. In addition, the Japanese were escorted on "extensive visits to the front line as well as military-economic facilities" and given instruction on projects that previously had been highly secret.
The German High Command, while fully intending to comply with Hitler's wishes, also sought to guard Germany's armament secrets. On 3 April the chief of the High Command, Field Marshal Wilhelm Keitel, addressed the order and stated that while admission of Japanese officials to German manufacturing and development facilities must be allowed, every effort would be made to "prevent [the Japanese] from obtaining a deeper insight into German armaments than we minimally have to provide to them.... Secret processes which involve advantages for the German economy and technology in the long term must be kept out of consideration."
As the war progressed, Japan's demands on the Reich increased dramatically in disproportion to those Germany made on Japan. Initially the Germans complied, as evidenced by a 19 March 1942 decision to grant a credit of 10 million Reichsmarks to Japan in payment for war materials already delivered. However, by August the Japanese requests were of such magnitude that Ambassador Oshima Hiroshi advised Tokyo that "Japan must take into account Germany's diminished supply reserve of munitions," as well as the fact that certain German companies were switching their production from machinery to munitions, thereby causing the cancellation of Japanese machinery orders.
Despite the shift in Germany's military-industrial priorities, Japanese orders continued to pour in unabated, and Germany, though with trepidation, did its best to accommodate its partner. However, as the conflict on the Russian front began to deplete German war material, Reich officials informed Oshima that Japan must consider changing the nature of its requests to those services and items that Germany could afford to provide. Consequently, on 9 December 1942 Japan and Germany finalized yet another cooperative agreement, this one addressing technical cooperation. The two Axis powers pledged to "exchange certain patents, licenses, and drawings [and to arrange] the sending of engineers ... and technical experts, and the practical training of technical experts."
Japanese officials had long been taking notice of German developments and subsequently sought patent approval for the Japanese manufacture of armaments and equipment. In September 1942 the Japanese diplomatic mission in Berlin had requested that the Ordnance Branch of the War Ministry in Tokyo seek the patent rights to several new German inventions, including an improved filtering system for air raid shelters, a portable device for evacuating poison gas, an improved valve for diving pressure chambers, and an underwater siren, used by divers "to scare off dangerous fish." Armed with the December protocol, Japanese industrialists now had the promise of technical expertise as well as patent rights and could begin putting German methodology into Japanese production.
By 1943 Japan was requesting increasing amounts of military hardware while requests for goods of an industrial nature had dropped dramatically, an indication that the Pacific war was straining Japan's ability to develop effective weaponry to counter the advances made by the Americans. For example, whereas the Imperial Army had previously sought to acquire a German manufacturing technique to produce cartridge steel for use in large gun barrel linings, by late 1943 this objective had been abandoned in favor of a request for finished goods, such as German artillery pieces. German artillery constituted the bulk of the initial armaments shipped from Germany, the most popular being the 10.5- and 12.8-centimeter antiaircraft guns, the versatile 88-millimeter field piece, and the 75-millimeter antitank gun, in addition to light weapons such as machine guns and automatic rifles. Germany also began to send rudimentary technology to Japan, as evidenced by the Würzburg and Rotterdam radar systems. By the spring of 1944 Germany had widened the scope of its armament shipments, which now included naval innovations such as a 750-ton submarine pressure hull as well as a Tiger tank.
However, the greatest area of Japanese interest was the field of aviation. In 1940 General Yamashita's investigative commission opened negotiations with the Junkers Aircraft Company, ostensibly to formulate an agreement by which Junkers aircraft would be produced in Japan. However, by the spring of 1941 the talks had stalled, resulting in Junkers representatives traveling to Japan to try to revive the moribund discussions. The Tokyo talks were more successful and reached fruition on 20 September 1941 with Junkers agreeing to allow the Manchuria Manufacturing Company to produce Junkers aircraft. Manchuria was no stranger to the German manufacturing processes; by 1940, as part of a previous agreement with Messerschmitt, the company was producing "twenty-five medium bombers and twenty ME 109s per month." To facilitate their own venture with Manchuria, Junkers agreed to send 115 technical personnel and tons of industrial equipment to aid in the setup and debugging of the manufacturing process.
In Berlin, however, the Luftwaffe High Command disapproved of the contract, citing the difficulty of sending the unusually large complement of technicians and industrial equipment to Japan, opting instead to furnish limited "technical knowledge and production experience," which would be considered 10 percent of Germany's total investment. Thus, Germany and Japan established an active trade that focused on the transfer of aircraft and aircraft components to Japan in return for vital raw materials such as wolfram (tungsten) and rubber. Both the Imperial Navy and Army air forces took immediate advantage of the exchange; by late 1944 Japanese officials had requested and received models and designs of some of Germany's most effective aircraft, including the Focke-Wulf (FW) 190 and Messerschmitt (ME) 109 fighters, the ME 110, ME 210, Henschel (HE) 129 and Junkers (JU) 88 attack planes, and the JU 188, FW 200, ME 264, HE 177, and Dornier (DO) 217 bombers.
It is no surprise that upon Germany's development of turbojet aircraft, the Japanese soon requested models and designs to help buttress their waning presence in the skies over the Pacific. In November 1944 Messerschmitt agreed to a contract that would result in the shipment of various Messerschmitt aircraft, including the turbojet ME 262 and rocket-powered ME 163. In addition, Messerschmitt agreed to send the appropriate technicians and engineers to aid Japan in establishing mass production of the new aircraft. These missions would be divided into three shipments: the first would carry the propeller-driven ME 309, 209, and 264, the second the jets ME 163 and 262, and the third the heavy fighter ME 410 and the transport ME 323. In addition to the aircraft, the cargo was scheduled to include a pressure cabin, fire-control computers, Lorenz 7H2 bombsights, a B/3 and FUG 10 airborne radar set, and 25 pounds of bomb fuses.
While the Japanese continued their aggressive pursuit of German innovations and personnel, the Germans' lingering distrust of their ally severely hampered the program's chances of success. German officials were reluctant to allow the trade of copyright and patent rights and would not authorize Japanese procurement of certain German armament projects lest secrecy be compromised. This bottleneck became a major sticking point in German-Japanese relations, and after discussions with Ambassador Oshima Hiroshi, Hitler once again stepped in. While his military leaders had severe reservations about granting the Japanese too much access to Germany's armament secrets, Hitler demanded that "in the interests of the joint management of the war," armaments, weaponry, and "practical knowledge" must be afforded the Japanese "on the broadest basis." In addition, Hitler ordered that the Japanese be instructed "through our initiative regarding all weapons and devices which ... could be used to advantage in the common cause." As a result, in November 1944 the Axis partners initiated negotiations for a secret convention that would address the matters of both patent rights and invention security. By the end of the year the convention was ratified and, in addition to inventions, guaranteed security and patent rights for "findings, experiences, manufacturing methods, and manufacturing instructions."
In August 1944 the Japanese mission in Berlin alarmed Tokyo by revealing that upon the assumed defeat of Germany the American victors "intend to transport at least 20,000 German engineers to the United States.... This would increase the armament potential of America in a way that could have decided effects on Japan." As a result, Tokyo now specifically requested the transfer of German technicians and engineers, ostensibly to prevent their capture by the Allies. In addition, the Japanese requests concentrated on inventions of importance to the war effort, with only a few specialists originally scheduled to accompany the necessary material. On 16 November 1944 Germany agreed to this proposal in principle and began transferring technical information and personnel for the construction of state-of-the-art weaponry, such as aircraft, high-speed submarines, and new antiaircraft systems. By the end of the year Ambassador Karl Ritter had finalized a plan to send twenty-seven German technical specialists to Japan to facilitate the development of V-weapons (rockets) and turbojet aircraft. In concordance with Ritter's efforts, Japanese liaison officers combed Germany for "highly qualified specialists" who could be induced to move to Japan, an effort in which Japan would "not shy back from any expenses."
The way cleared for a resumption of material shipments to Japan, discussions began concerning specific missions. On 25 November 1944 the OKM initialized such a mission by informing the naval attaché in Tokyo, Adm. Paul Wennecker, that to ensure closer collaboration in technical matters German specialists "with most recent experiences" would be sent to Japan to serve as aides at the disposal of the Japanese. The OKM also noted that since the Japanese had bemoaned the lack of a technical staff for Wennecker, immediate steps were being taken to remedy that situation as well. The first appointment was that of Cdr. (Freggatenkapitän) Gerhard Falcke—a prominent naval architect and propulsion engineer who was highly regarded by Admiral Nomura and other members of the Japanese naval attaché mission in Berlin—as Wennecker's technical assistant on naval matters. In addition, Heinz Schlicke, a renowned researcher in radar and electronics, would accompany Falcke to aid the Japanese in his professional capacity and to serve as a technical interpreter.
Because Germany's naval war was limited to submarine and coastal actions, there was no opportunity for Kriegsmarine officers to gain the experience in fleet actions they would need to rebuild the German fleet. Consequently, on 3 December Grand Admiral Karl Dönitz announced that he planned to send a contingent of naval officers to Japan to benefit from the large-scale operations of the Pacific war. Two naval officers, Lt. Cdr. (Kapitänleutnant) Richard Bulla, a naval aviator instructed to study the success of the Japanese naval air force, and 1st Lt. (Oberleutnant) Heinrich Hellendorn, a specialist in shipboard antiaircraft gunnery, were directed to report to Tokyo. Dönitz had initially proposed that Bulla and Hellendorn be assigned as auxiliary officers to the Imperial Japanese Navy and serve under the command of Japanese officers. However, the German Foreign Office opposed the assignment, opting instead for Bulla and Hellendorn to be assembled into an independent technical staff, to avoid "politically undesirable contingencies." The Foreign Office explained its objection by pointing out that Japanese naval officers in Germany did not serve under the Kriegsmarine but rather under the Japanese embassy. Upon further consideration, Dönitz agreed and reassigned Bulla and Hellendorn as members of the German naval attaché's technical mission. In addition to Bulla and Hellendorn, Kay Nieschling, a military judge, was assigned to Tokyo to direct German military jurisdiction in Japan as well as to investigate the aftermath of the Sorge spy scandal. Bulla, Hellendorn, Falcke, Schlicke, and Nieschling were scheduled to depart Germany in late January 1945.
On 1 September 1944 Reichsmarschall Hermann Göring appointed Gen. Ulrich Kessler as Luftwaffe military attaché to Tokyo. Kessler, not entirely thrilled at the prospect of serving out the war in Japan, nevertheless accepted his mission. He was ordered to form a liaison staff and subsequently requested that "a considerable number of officers" accompany him to Asia to form an "Expanded Office of Air Attaché." Although not allowed his "considerable number," Kessler nonetheless was able to acquire the services of antiaircraft specialist Lt. Col. (Oberstleutnant) Fritz von Sandrart and radio and reconnaissance specialist Erich Menzel, who were to assist the Japanese in preparing adequate defenses for the home islands. In late December the general and his party were informed that they too would be departing Germany in January 1945.
Also scheduled for a January departure were two civilians, August Bringewald and Franz Ruf. Both men were employees of Messerschmitt, Bringewald as an engineer and Ruf as a manufacturing and procurement specialist, and they were assigned to "assist and arrange mass production of the ME 163 and ME 262 airplanes." Bringewald, who did not want to go to Japan, had been scheduled for an earlier departure; however, prior to leaving he had a premonition of disaster and subsequently requested that he be allowed to wait. Although his request for a delay was granted, his wish to remain in Germany was not, and he, along with Ruf, likewise prepared to depart Europe in January 1945.
Because of the difficulty of traveling to Japan from Europe, all of the personnel scheduled to leave Europe were combined into a single mission. German officials, particularly Göring, desired a January 1945 departure and determined that travel by air would be the quickest way. Three Junkers 290 transports were selected for the trip; however, this plan was discarded in deference to Japanese fears that the aircraft might be forced down into Soviet territory and thus jeopardize the fragile Japanese-Russian nonaggression pact. Finally, because the transport of individuals was not space-intensive, the decision was made to send the contingent to Japan via submarine.
The exchange of material between Japan and Germany was the result of a cooperative effort directed through distinct military and diplomatic channels. In 1943 Admiral Dönitz, while developing the command structure for East Asian operations, designated Paul Wennecker, German naval attaché to Japan, as area commander for all German naval activities in the Far East, including the supply exchange program with the Japanese. To help coordinate matters, two members of Wennecker's staff, Commander (Fregattenkapitän) Souchon and Commander (Korvettenkapitän) von Krosigk, were charged with consulting with Japanese military officials to determine which items would be included in the cargo inventory. In addition, the Japanese ambassador in Berlin, Oshima Hiroshi, maintained liaison with the Imperial Army and Navy and forwarded their most urgent requests through diplomatic channels in meetings with German foreign minister Joachim von Ribbentrop and, often, Hitler himself. This information was subsequently relayed to the Kriegsmarine Supply Office in Berlin, where the requests were processed and delegated to the proper procurement authorities, who in turn would direct shipment of the material to the French port of Bordeaux.
By the spring of 1945, even while preoccupied with its futile efforts to stave off impending defeat, Germany nevertheless continued to attempt last-minute shipments of contraband to Japan. In the Pacific, Japanese dependence on German assistance had reached desperate proportions. On 9 April 1945 Vice Adm. Abe Katsuo, Japan's representative to the Tripartite Commission in Berlin, reported to Tokyo that he and his staff, in an effort to "have the Germans contribute to Japan's prosecution of the war directly and indirectly by having them fight on as long as possible," had been trying to convince the Germans that the two countries "have a common destiny not only in this war, but in times to come." On 3 May, after a meeting with German foreign minister von Ribbentrop, Abe assured Tokyo of Germany's commitment to Japan, reporting that von Ribbentrop had "prayed that strenuous efforts might be made to increase ... cooperation with Japan more and more." However, the Axis partners were once again faced with the dilemma that had plagued the cooperative effort since the beginning of the war: the problem was not so much what to send as how to send it.
In 1940, when Germany and Japan signed the Tripartite Pact, the means of shipping the contraband of cooperation had been the least of their worries. During the first five months of 1941, for example, Germany had received 212,366 metric tons of commodities from Japan via the Trans-Siberian Railroad, while in return Japan received heavy machinery, armor plating, vehicles, and even aircraft. However, the 1941 German invasion of Russia closed this vital artery, forcing Germany to explore other means of transport. The obvious solution seemed to be transport by air.
On 11 December 1941 Germany, Italy, and Japan amended the Tripartite Pact with a "Military Agreement" defining each signatory's military sphere of operation. More important, however, the agreement called for the establishment of transport routes, preferably by air, among the three allies, as well as the restoration of preexisting shipping routes via the Indian Ocean, all of which would facilitate Japanese-German cooperation. However, air transport proved difficult, for the most logical route from Europe to Asia violated Soviet airspace, and alternative routes over India were too lengthy for existing aircraft to undertake. As a result, the bulk of Axis merchant shipping would be conducted by blockade-runners.
The surface vessels on which Germany and Japan were to rely were known as Yanagi transports. Between April 1941 and May 1942 the initial Yanagi missions, which carried scarce raw materials to Germany and machinery to Japan, resulted in six German vessels escaping the Bay of Biscay, while another twelve arrived in Bordeaux from the Far East. During the early stages of operations the British possession of the Enigma decrypting apparatus did little to deter the Yanagis; by June 1942 only three blockade-runners had been sunk, and one of these mistakenly by a U-boat. Britain's Ministry of Economic Warfare calculated that during the first six months of 1942, Axis blockade-runners had delivered 60,000 to 65,000 tons of rubber, wolfram, and other scarce commodities to Germany; if this figure reached the 100,000-ton plateau, Germany's needs for 1942 would be met. Despite the Admiralty's introduction of increased antishipping measures, the Yanagi missions did not suffer substantially.
The Yanagi missions declined in late 1942, when British interception of Japanese diplomatic decrypts provided advance information of ship movements. This information, in addition to successful Royal Air Force mining of the Bay of Biscay and the concentration of warships that accompanied the Torch convoys, severely disrupted the blockade-runners' effectiveness. By the end of April 1943 Germany had received only 28,500 tons of rubber, or less than one-third of what had been received the previous year, and Allied surface vessels and submarines had cost Germany over 55,000 tons of scarce resources like tin and tungsten. During the period from September 1942 to April 1943, seventeen merchantmen left French ports for the Far East; of these, three returned to port and four were sunk, with the remaining ten reaching Japan. However, during this period only five departed after December 1942. By November 1943 blockade-running was considered so dangerous that Ambassador Oshima recommended that ships' captains receive decorations before they sailed. As a result, the Special Staff for Economic and Commercial Warfare Measures reported to General Field Marshal Keitel that a review of shipping totals for 1943 indicated the "termination of surface blockade running."
In his 31 March 1943 report to Tokyo, Oshima described a conversation with Field Marshal Fritz Erich von Manstein, whom Oshima identified only as "MA." During this conversation von Manstein informed Oshima that "Germany regards it as exceedingly urgent that effective liaison be made between Japan and the Reich ... as it has recently gotten too hot for blockade-running ships, we think we are going to use submarines," and he indicated that plans were already under way to reconfigure older submarines to perform cargo-carrying missions. Oshima suggested that, in addition to cargo, the two allies might also consider exchanging personnel via submarine, to which von Manstein readily agreed. As a result, Germany planned to send three submarines to Japan in May 1943, to be followed by four more in June.
During prewar planning sessions, Admiral Dönitz had already proposed the deployment of U-boats on transport as well as attack missions. By 1941 the idea of an expanded role for U-boats had begun to intrigue even the Führer; in a 13 December meeting Hitler had informed Oshima that Germany desired to establish consistent channels of contact with Japan, and "if nothing more than people are concerned, we expect to accomplish this by use ... of submarines." However, Kriegsmarine commander-in-chief Grand Admiral Erich Raeder had refused to allocate funding to the development of large cargo-carrying submarines, opting instead' to finance construction of more surface vessels, and hence the submarine cargo mission was temporarily shelved as a low priority.
On 30 January 1943 Karl Dönitz succeeded Raeder as the head of the Kriegsmarine, and he promptly resurrected the submarine cargo plan by authorizing the reoutfitting of existing submarines to transfer goods and personnel from Europe to the Far East and back. Japanese possession of strategic Southeast Asian islands, all of which could be used as submarine bases, generated additional interest within the OKM as to the feasibility of U-boat voyages to the Indian Ocean and the transfer of equipment and cargo at sea. For now, the success of Germany's blockade-running program, along with the Kriegsmarine's need for combat submarines in the Battle of the Atlantic, precluded any attempt to initiate regular submarine service to the Far East. However, by the spring of 1943 Germany's blockade-running missions had been severely crippled; of the thirty-four vessels allocated to run the blockade, seven had turned back to Europe because of British pressure, while eleven others had been sunk by Allied hunter-killer groups.
By mid-1944 the Kriegsmarine could no longer guarantee German merchantmen safe passage to the Far East. Shipments between Japan and Germany suffered accordingly, but by no means did they shrink in importance. Indeed, as the war progressed, Japan became increasingly dependent on Germany for aid in the defense of the home islands. Transport had become not simply a matter of convenience to the Japanese but rather one of survival. A method of conveyance would have to be found, and given the scope and size of the requested shipments, the Axis partners had few options.
Because the principal barrier to German surface trade was Allied control of the sea, the Kriegsmarine had little choice but to enlist its U-boats, and by mid-1943 the bulk of trade from both Germany and Japan was being conveyed by submarines departing from German-occupied ports along the French coast. However, German submarines in their current configuration did not lend themselves to the cargo mission. Storage inside a U-boat was at a premium, with only 1 cubic meter (1.3 cubic yards) available for each metric ton of cargo; in general, most freight was bulky, requiring at least 3-4 cubic meters (4-5 cubic yards) per ton. In addition, while every available space on board was utilized for cargo, the submarine had to be packed with buoyancy in mind.
While the availability of U-boats of sufficient size and range was a primary consideration, any decision about which submarines to use would also have to take into account the type of cargo being transferred to the Far East. The Kriegsmarine's initial priority for its submarines was the delivery of its own equipment to German facilities in the Pacific, such as the submarine base at Penang. To provide the necessary room for these items, the OKM proposed that 80 to 100 tons of keel ballast be removed. However, stowing cargo in the keel compartments was no easy matter, because of the requirements of the submarine's balance and trim. Originally, iron tubes filled with mercury, along with bars of lead, both of which were in great demand by the Japanese, were successfully used to fill the keel spaces. However, with the depletion of German stocks of lead and mercury, other items would have to be found that could both satisfy the Japanese and provide the proper keel ballast for the submarine.
At first the OKM engineers attempted to fill the keel spaces with aluminum, which the Japanese had purchased in great supply, and optical glass. However, because of their light weight, both aluminum and glass could only be stored in the keel in relatively small amounts. To assure the appropriate weight for ballast, large amounts would have to be secured in the keel, leaving insufficient room for heavier items. German engineers next considered using specially machined bar steel, of which the Japanese had purchased and stocked several hundred tons. However, the steel was machined into bars 3-5 meters (9.8-16.4 feet) in length—too long to fit into the keel spaces. As a result, the Special Staff ordered that lateral compartments be built into the keel spaces to accommodate lengthy items. This upgrade was of sufficient success that all transport boats were reconfigured to include the lateral keel compartments; in addition to allowing the shipment of items of excessive length, the compartments could accommodate up to 30 tons of vital contraband such as rubber on the return trip to Europe.
In January 1943 Oshima had informed Hitler that the Japanese were considering the construction of freight-carrying submarines to avoid the dangers of surface transport. Impressed, Hitler now directed the Kriegsmarine to embark on a similar construction program for a fleet of Type XX U-boats with a carrying capacity of 500 tons. Scheduled for completion by mid-1944, twenty such submarines would, according to German estimates, be able to transport up to 20,000 tons of supplies from the Far East annually,so However, several factors doomed Hitler's ambitions. Allied antisubmarine countermeasures proved more than a match for the prototype of the new boats, and subsequent modifications were both ineffective and impractical. In addition, the Special Staff of the OKM determined that each cargo U-boat built would mean one less operational boat, and so the new cargo boats were deducted from the operational estimates for 1946. As a result, Dönitz was forced to cancel the building program, and alternative methods, such as the towing of underwater cargo containers and the use of Italian submarines, failed. The Kriegsmarine was forced to search for other options and eventually returned to a program of reconfiguration.
Germany's operational requirements for attack submarines meant that any undersea transfer of material to Japan would have to be handled by those boats that Dönitz could afford to spare from operations in the Atlantic. By 1943, because Germany's fortunes at sea depended heavily on the offensive U-boat campaigns in the Atlantic, only a few U-boat types remained available for cargo duty. The oceangoing Type IXD was originally used for the bulk of the long-range cargo missions, but the growing need for offensive-capable boats in the Atlantic saw increasing numbers of the IXDs leave the cargo mission. As a result, in July 1943 two Type IXD boats were joined by nine IXC boats and one XIV tanker to constitute the "First Monsun Group," or the Far Eastern cargo U-boat group.
The results of the Monsun missions were mixed, at best. In 1944, nineteen U-boats of the Second Monsun Group were dispatched to the Far East, each with storage in both the keel and hull spaces. The keel cargoes consisted of mercury, lead, steel, uncut optical glass, and aluminum; the hull spaces contained blueprints, drawings, and models of weapons and vehicles. By the end of the year eight of the U-boats had reached their destination, six had been lost, and the remaining were still en route. In other words, of the 1,801 tons of goods shipped from Europe, 755 tons actually arrived, 615 tons were lost at sea, and 491 tons were in transit. Of the twelve boats that left the Far East in 1944, three arrived in German-controlled territory, four were lost, and five were forced to return to their points of origination. The total delivery of these boats was 434.7 tons, 390 tons of which was rubber and tin.
Cognizant of the declining numbers of submarines adaptable to the cargo mission, Dönitz decided to utilize the 1,600-ton Type XB minelayer, of which only a few remained. These boats, which had previously performed the dual role of minelaying and refueling, would bear the brunt of Germany's material exchange during the latter stages of the war; by April 1943, nine Type IXD and XB U-boats had been assigned to Far Eastern transport duty, with expectations of two round trips per year. Still, the dearth of submarines concerned Dönitz: operational planning for 1945-46 depended on Far Eastern commerce to maintain material stocks at sufficient levels to defer the further use of the scarce U-boats for the cargo mission.
Even with the dubious results of the submarine cargo mission, the logistics of undersea cross-oceanic commerce were staggering, and it required special talents to coordinate the vital merchant exchange between Germany and Japan. Following the German occupation of France, Germany designated several French ports as points of origin and reception, naming Bordeaux as the headquarters for all of Germany's foreign trade. The organization that controlled Germany's blockade-running and, later, submarine commerce was known as the Marinesonderdienst-Ausland (MSt)). While Germany initiated the bulk of its commerce from the Bay of Biscay, Japan designated Kobe as its principal receiving port; indeed, by February 1942 traffic into Kobe was so heavy that the OKM assigned additional traffic-control personnel in the persons of Fritz Ernst Muff and Hans-Joachim Rohreke to assist the Japanese in coordinating it.
Earlier in the war the MSD had directed all of Germany's blockade-running traffic by coordinating the ships and their bills of lading with timely dispatches, all of which had to be organized in step with the fortunes of the war at sea. To ensure success, the MSD maintained liaison with the civilian and military shipping agencies of all of Germany's trading partners, as well as the operational and intelligence arms of the Kriegsmarine. In addition, the MSD provided training for officers who would need experience traveling in foreign seas. During the early days of the war, when German blockade-runners and auxiliary cruisers roamed the southern seas, many officers graduated from the MSD'S training school. One of them was a young junior ordnance officer, headed for sea duty aboard the raider Atlantis, named Johann Heinrich Fehler; another was an administrative officer named Becker who would one day head the MSD. Nevertheless, the MSD'S primary mission remained the direction of outgoing and incoming commerce and the establishment of efficient methods of transport through seas that were becoming increasingly difficult to traverse.
In consideration of the ninety-day trip to Japan, Germany and Japan designated the months of February, May, September, and November as the prime "season" for trade. In order to avoid enemy patrols and facilitate refueling at sea, a distinctive route was designated. A ship leaving from Bordeaux would proceed to longitude 21° west, then turn due south toward the Antarctic. As the vessel approached the tip of Africa, she would alter her course so as to shadow the coastline, proceed around Cape Horn, then continue on to either Kobe or one of five German Far Eastern bases. However, Allied advances in countermeasures, particularly in the field of radar, took a heavy toll on the existing transports, and the Cape Horn route was discontinued in late 1941. The new route, which led U-boats around the Cape of Good Hope, fared only marginally better. By the fall of 1943 the losses of transport U-boats nearly matched those of their surface predecessors; of twelve U-boats that departed Japan for Europe, only four reached Bordeaux.
The success of Germany's submarine service to the Far East was dubious. While the advantage of stealth did allow some U-boats to arrive in Japan when surface ships probably could not have, the overall effort was a case of too little too late. All of the material transported to Japan by all of the U-boats that survived the journey amounted to approximately one-eighth of the cargo that a single blockade-runner could have carried. By the spring of 1945 Germany's attempts to keep Japan fighting were being hampered as much by unreliable means of delivery as by the lack of materials to transport.
During his last weeks in Berlin prior to Germany's surrender, Vice Admiral Abe renewed Japan's requests that Germany send submarines to the Far East both to engage the American navy, which had all but annihilated Japan's own submarine and surface force, and to bring munitions and weaponry to help Japan stave off the anticipated American invasion of the home islands. On 5 April 1945 Abe sought to discuss the matter personally with Hitler but, unable to obtain an audience with him, met instead with Field Marshal Wilhelm Keitel and Foreign Minister Joachim von Ribbentrop, neither of whom could offer a commitment. In a 15 April meeting Dönitz informed Abe that Germany could no longer afford the fuel required to send U-boats to the Far East, and in any case the OKM considered the entire operation "a waste of time." Time was running out for the German Reich and, for that reason, also for the Japanese empire.
Abe returned to Dönitz for one last, desperate attempt to acquire help. Dönitz, who sympathized with his Japanese ally, could offer nothing more than before, once again citing the shortage of fuel. Although the refusal to dispatch more submarines was Germany's final official answer to Tokyo's requests, Dönitz did inform Abe that what little Germany could do had already been initiated: "There are only two or three submarines of the large type which can be sent to Japan," he said. "Of those, one is already on its way." The vessel to which Dönitz was referring was a Type XB former minelaying submarine, which had left Kristiansand, Norway, in March and was identified by the designation U-234.