Economic cooperation: the transfer of raw materials

Collaboration between belligerents does not necessarily imply direct military cooperation, even though this epitomizes wartime relations. Indeed, from a Japanese viewpoint, the essence of the pact with Germany, at least during the first two years of its existence, was first and foremost political, and only then economic, military, and ultimately also ideological.Footnote ⁷ Its immediate objective was to facilitate Japan’s plans for expansion in Southeast Asia, thereby securing the region’s Western colonies and utilizing their resources for its own needs. To this end, Japan needed to deter the United States from waging a two-front war, and consequently to avoid confrontation altogether. At the same time, it had to establish its own paramount position in the region vis-à-vis Germany, and thus to prevent the latter from taking over the Southeast Asian colonies belonging to the European countries it had just seized.Footnote ⁸ Germany set similar objectives with regard to its plans for expansion, although it placed a greater emphasis on the economic aspects of the alliance. It conceived it as a means of harnessing substantial cooperation with Italy and Japan, and thus allowing Germany to match the Anglo-French economic potential, all the more important in case of active American or Soviet involvement.Footnote ⁹

With these political ends in mind, it is important to note that the signing of the Tripartite Pact between Germany, Japan, and Italy on 27 September 1940 did not initially lead to a breakthrough in either military or economic relations between Japan and its allies. Similarly, the Pact did little to diminish the mutual suspicions and tense relations between Tokyo and Berlin. Only a few years earlier, and despite the Anti-Comintern Pact signed between Japan and Germany on 25 November 1936 (Italy joined a year later), the two countries were on the opposing ends of a titanic struggle in China, and as late as the outbreak of the Second Sino-Japanese War in the summer of 1937, Germany still served as Nationalist China’s major weapons supplier.Footnote ¹⁰ In February 1938, however, the Nazi regime became convinced that Japan could provide it with greater economic opportunities than war-torn China, and so put an end, at least officially, to its pro-China policy, and recognized the Japanese-controlled puppet state of Manchukuo.Footnote ¹¹ The conclusion of the Tripartite Pact two years later and Japan’s entry into the war in December 1941 strengthened Japanese–German relations. Nevertheless, Tokyo, like its ally, kept its strategic cards close to its chest, and remained unswerving in its determination to prevent Berlin from obtaining free access to the vast Chinese market and to Southeast Asia’s raw materials.

During the first years of the war in Europe, economics and the settlement of economic disputes formed the crux of Japanese–German relations. Upon the German conquest of the Netherlands and France, and even more so after the Japanese takeover of Southeast Asia almost two years later, the two nations were still grappling with various forms of economic discord, especially over their respective rights to exploit the natural resources of the French and Dutch colonies in Southeast Asia. However, as the fighting in Europe continued, economic issues (notably shortages of certain raw materials) became a growing motive for improving relations between the two nations. During their negotiations, both sides had pressing needs that could not wait for the conclusion of the imminent agreement. Tokyo required certain military technologies and some raw materials that its main European ally already possessed, and also needed new markets for its Southeast Asian products in order to keep the local economies alive. Berlin, in contrast, was desperate for certain raw materials that its Asian ally monopolized in Southeast Asia. These materials included, among others, tungsten, which was used for hardening metals (in items such as turbines and armour-piercing munitions) and for making wear-resistant abrasives; tin, which was used in alloys, as a solder, and for plating steel containers meant for food preservation; bauxite, for the production of aluminium used in various forms of military equipment such as tanks and industrial machinery; and, most significantly, natural rubber.Footnote ¹²

Rubber had been used in all complex weapon systems since the early twentieth century, and thus became an indispensable raw material for wartime economies. Its military importance, alongside its growing scarcity in Germany and its availability in the newly gained territories of the Japanese empire, made natural rubber the prime raw material present in the economic exchanges carried out by these Axis powers during the war, as well as providing an indirect impetus for the enhancement of their military cooperation. Before the Second World War, Germany was a world leader in the development and production of synthetic rubber, primarily from coal and limestone, and later from natural gas too.Footnote ¹³ Synthetic rubber was nonetheless the product of an emergency, produced because of the insufficient and unstable supply of natural rubber, and as a rule inferior to the latter. However, the production of synthetic rubber did not meet Germany’s projected and actual military demands. Critically, it was also inadequate for the production of high-performance engineering and military components.Footnote ¹⁴ For instance, synthetic rubber tyres with large cross-sections tended to crack, especially at low temperatures. Hence, natural rubber remained an essential material for the production of many military articles from gas masks to large tyres.Footnote ¹⁵

Natural rubber had one major disadvantage, however, as far as the European Axis countries were concerned. It could not be produced in Europe or in any other territory occupied by Germany or Italy. Extracted mostly from the tropical Pará rubber tree, it was mainly produced in Southeast Asia (85% of world production in 1939). Its largest producers were British Malaya (present-day Malaysia and Singapore), with 39% of world production, and the Dutch East Indies (present-day Indonesia), with 38%.Footnote ¹⁶ Although Germany was not the only industrialized country dependent on the importation of Southeast Asian rubber, Adolf Hitler was all too aware of the German war machine’s precarious dependence on foreign raw materials and so had aspired to economic autarky since his rise to power.Footnote ¹⁷ It was with this fear of deprivation and scarcity in mind that he forged close relations with IG Farben, the single German producer of synthetic rubber. Through a long list of contracts for the rearmament of the German war machine, the company (by then the world’s third largest synthetic rubber producer) soon became ‘an instrument and an agency for the policies of the Nazi government’.Footnote ¹⁸

A few years earlier, IG Farben had formed a cartel with Standard Oil, and by 1935 German chemists had succeeded in producing the first of a series of synthetic rubbers known as Buna rubbers (through the polymerization of butadiene with styrene).Footnote ¹⁹ Nonetheless, Buna production remained very low, and so Germany’s rubber plants relied on stocks of raw materials sufficient for more than two months’ worth of production.Footnote ²⁰ This state of affairs did not last long. In 1937, the year that German imports of natural rubber reached their zenith, the Nazi regime embarked on a Four-Year Plan under the direction of the commander-in-chief of the Luftwaffe, Hermann Göring. The plan aimed for national autarky, and included the increased production of Buna as one of its main goals. Yet, despite growing production, the availability of natural rubber remained one of Hitler’s concerns well into the war.Footnote ²¹ Undeniably, his apprehension was quite warranted, since until 1940 Western democracies monopolized no less than 93% of the world’s production of natural rubber, and this situation had not changed substantially a year later, despite Germany’s sweeping victories in Europe.Footnote ²²

Concerned by the supply of vital raw materials during 1940–42, German strategists paid increasing attention to the economic potential of Europe’s colonies in Southeast Asia, and surveyed the various options available for transporting their vital raw materials.Footnote ²³ Natural rubber was given particular consideration. Since the outbreak of the war, the Axis powers had been short of this material owing to the Allies’ control of its production, but in 1940 Germany managed to get hold of large stockpiles of natural rubber in France that solved their shortage temporarily. In addition, Germany, and to a lesser extent Italy, was able to import strategic raw materials, including rubber, from Southeast Asia via the Trans-Siberian Railway. In the spring of 1941, however, Germany terminated the use of this important overland route because of its advanced plans for an invasion of the Soviet Union (Operation Barbarossa). From April 1941 onwards, German blockade-runner (Blockadebrecher) merchant ships and a few Italian vessels replaced the Soviet trains. Until the end of the year, these ships had to load rubber imported from Southeast Asia at ports under Japanese control, most notably Dairen (present-day Dalian) in north-eastern China, and Kobe in Japan.Footnote ²⁴

A major turning point in the German quest for Southeast Asian rubber occurred on 7 December 1941, with the Japanese onslaught on Pearl Harbor and the subsequent outbreak of the Pacific War. In the following months, Japan took over both Malaya and the Dutch East Indies, the world’s leading exporters of natural rubber. Hitler’s could not conceal his delight at the abundant ‘rubber, oil, zinc, tungsten, and a number of other products’ which fell suddenly into Japanese hands, remarking that ‘Japan will be one of the richest countries in the world. What a transformation!’Footnote ²⁵ The joy over the presumably easy access to rubber was short-lived as the Allied powers did their utmost to prevent Germany and Italy from obtaining natural rubber and other raw materials. Soon, a bitter struggle for the procurement of natural rubber began to take shape on both sides.Footnote ²⁶

Loading their cargo directly in Southeast Asian ports, blockade-runners remained the only means for transporting rubber and other raw materials to Germany. They usually circumnavigated Africa and carried back from Asia badly needed materials for the European Axis powers’ war effort. Known in the Imperial Japanese Navy (Dai-Nippon Teikoku Kaigun, henceforth IJN) by their code name Yanagi-sen (‘willow ships’), between 1941 and 1944 these ships delivered 43,983 tons of natural rubber to the German and Italian war industries. They also carried 68,117 tons of other essential materials, mostly from Southeast Asia, such as tungsten, tin, and quinine, and altogether about two-thirds of the German annual requirement for these items.Footnote ²⁷ These figures nonetheless conceal a dramatic development. Although by mid 1942 Germany and Italy had unlimited access, at least in theory, to natural rubber, shipping it safely to Europe became extremely dangerous.Footnote ²⁸ This situation prompted increasing cooperation between German and Italian commercial representatives in East Asia, but their options were limited.Footnote ²⁹ While the only viable route was now via the sea, the Allies’ blockade became so effective, especially after the introduction of the Checkmate System on 8 June 1943, that fewer and fewer Axis blockade-runners succeeded in reaching Europe.Footnote ³⁰ By late 1942 and early 1943, only one of the six ships that left for Europe reached its destination.Footnote ³¹ As the toll of using surface ships became unbearable, this route was virtually terminated by the end of 1943.

Transporting raw materials by submarine now became the only feasible option. While German strategists began to consider the use of older submarines for cargo-carrying missions in March 1943, the IJN had already examined this route a year earlier.Footnote ³² On 22 April 1942, the I-30, a large 3,717-ton (submerged) Type-B1 cruiser submarine, under the command of Commander Endō Shinobu, departed from Penang, Malaya, with a vital cargo for Germany.Footnote ³³ When the submarine arrived in Lorient, France, on 5 August 1942, it delivered 1,500 kg of mica and 660 kg of shellac for use in electrical capacitor devices and military pyrotechnics, respectively.Footnote ³⁴ Holding a banquet dinner for the newly arrived crew in the Grand Hall of the former French naval arsenal, the German authorities at the port were mindful of the importance of the visit. Endō, along with a few members of his crew, even travelled to Berlin, where Hitler himself awarded them a medal.Footnote ³⁵

The Führer’s token of respect for the crew was by no means casual. Before the war, the long-lasting racial bias against East Asians in Germany, much as in other parts of Europe, had revealed itself in everyday acts of discrimination against Japanese (euphemistically referred to occasionally as ‘honorary Aryans’) residing in the German Reich.Footnote ³⁶ By the summer of 1942, however, Hitler seemed to have somewhat overcome his prejudice and suspicion towards the Japanese, or had at least become, as the historian Ernst Presseisen noted, ‘enough of a politician not to let his ideology get in the way of his diplomacy’.Footnote ³⁷ In a reception Hitler held for the Japanese ambassador to Berlin, Lieutenant General Ōshima Hiroshi, seven days after the outbreak of the war in the Pacific, he confessed that ‘for Germany [and himself] the entry of Japan into war is a great relief’.Footnote ³⁸ What was at stake was obviously more than natural rubber and a few other raw materials, although economics still remained a prime element in German–Japanese relations. As both parties regarded the exploitation of Southeast Asia as a major issue in their long-term planning, German–Japanese negotiations over the region’s colonial resources took longer than initially expected.Footnote ³⁹ The fact that relations between the two allies were far from firm did not ease the negotiations.

On 20 January 1943, however, Japan and Germany consolidated their economic relations in a long-awaited agreement entitled Abkommens über wirtschaftliche Zusammenarbeit (Agreement on Economic Cooperation).Footnote ⁴⁰ This finally secured Germany preferential treatment in Greater East Asia while confirming Japan’s economic hegemony over the European colonies it occupied.Footnote ⁴¹ On the German side, the achievement was the brainchild of a single individual: Germany’s economic envoy in Japan, the state councillor (Staatsrat) Dr Helmuth C. H. Wohlthat (1893–1973). Two years earlier, when Tokyo began to ask for technological aid, Berlin was not blind to the sudden opportunity to press for the long-coveted preferential status in China, and dispatched Wohlthat to negotiate. Arriving in Tokyo on 22 April 1941 as the head of Berlin’s economic delegation, he was attached to the German embassy. This ‘Wohlthat Mission’ was not intended to last long but, in the wake of the attack on the Soviet Union two months later, he was forced to stay in the Japanese capital until the end of the war.

As the chief economic negotiator (Wirtschaftssachverständiger) in the Japanese empire, Wohlthat was in charge of promoting the commercial status of the Third Reich in Greater East Asia, and gaining access to essential raw materials found in the entire region under Japanese control.Footnote ⁴² It was not until August 1943, however, that another outstanding economic dispute between the two nations was finally resolved with Wohlthat’s mediation. This concerned the compensation that Japan was to pay to IG Farben for disclosing new technical data on the production of synthetic oil.Footnote ⁴³ Thereafter, the flow of raw materials from Asia to Germany and military technology to Japan became relatively smooth, although losses en route grew alarmingly large. In addition, on 25 September 1943, the Imperial General Headquarters–Government Liaison Conference decided, partly because of Wohlthat’s involvement since 1941, to modify its previous policy of systematically ousting German trade from its occupied territories, and to compensate German firms for the losses incurred in Japan’s onslaught on Southeast Asia.Footnote ⁴⁴

Thereafter, the availability of raw materials no longer bothered the European Axis powers, but rather their safe transport to Europe. In early 1943, it became evident that the Allies controlled the surface of the Atlantic Ocean and were implementing an ever more successful blockade in those waters and in the Indian Ocean. German shipyards, on the other hand, were reaching an all-time record of a monthly average of 23.3 submarines commissioned through 1943 (a total of 279 vessels).Footnote ⁴⁵ Submarines thus seemed to hold the key for the transport of vital raw materials. In January 1943, Ambassador Ōshima met Hitler and reported on Japan’s plans to build particular cargo-carrying submarines.Footnote ⁴⁶ Although it took another seven months before a second Japanese submarine reached Europe, the news exerted an undeniable impact. Dazzled by Ōshima’s report, Hitler instructed his navy to build a fleet of transport U-boats, and consequently, during the same year, thirty relatively large Type XX U-boats were laid down.Footnote ⁴⁷

Believing that the Anglo-Saxon nations could only be overpowered ‘at sea’, Grand Admiral Karl Dönitz, the newly appointed commander-in-chief of the German Navy (Kriegsmarine), remained hesitant.Footnote ⁴⁸ He preferred to employ his U-boats against Allied convoys and thus advised Hitler on 20 February 1943 to first use a number of large and slow-diving Italian Navy (Regia Marina) submarines for freight-carrying missions to Southeast Asia. In exchange for more advanced German Type VII U-Boats, Italy allocated seven submarines for the mission, the first of which left Bordeaux on 11 May 1943 carrying tank blueprints, bomb prototypes, and gun ammunition, as well as a small quantity of raw materials (mercury and steel). Under the code name ‘Aquila’, five of these vessels left France for the Indian Ocean, although, ultimately, only three reached Southeast Asian waters.Footnote ⁴⁹

The Italian submarines were only a vanguard. Starting in the latter half of 1943 and until the German capitulation, the three Axis powers’ submarines sailed to Asia and back, each carrying a small cargo of up to 160 tons in their narrow hulls.Footnote ⁵⁰ Like their predecessor merchantman blockade-runners, they usually offloaded or loaded their valuable cargo at Southeast Asian ports, and did not fare much better than the former. Among the tens of German and Italian submarines that were sent to the Indian Ocean and the four Japanese ones that left for Europe, only a fraction succeeded in making their way back or surviving the war. In 1944 alone, nine of the twelve submarines that left for Europe were sunk or forced to return. Altogether during 1944–45, these submarines carried 2,606 tons of vital raw materials (mainly tin, rubber, tungsten, quinine, and opium, in descending order) from Asia to Europe and 2,070 tons (made up of mercury, lead, aluminium, glass, and steel) in the opposite direction. In fact, due to the high ratio of losses en route to Europe, no more than 611 tons of materiel (23.4% of the total carried) arrived in Europe – considerably less, ironically, than the materiel (869 tons or 42% of the total) which managed to arrive in Asia.Footnote ⁵¹

No less telling is the fact that, of this very limited amount of raw materials reaching Europe, only 434 tons arrived in time to be used by the German war industry.Footnote ⁵² This bottom-line figure, as much as the heavy toll in human lives and submarines exacted for it, reveals the futility of using submarines as cargo vessels from Southeast Asia during the final two years of the war. Germany and Japan were not blind to this futility. But as the economic exchange was merely one aspect of the Axis cooperation in the region, the operation of submarines seemed to be a sound investment.

Naval cooperation: submarine warfare and technology

The inter-Axis connections in the Indian Ocean reached their peak in naval combat cooperation. However, this could only be attained once Japan entered the war against the Allies. Indeed, four days after the outbreak of the Pacific War, representatives of the three Axis empires convened to ensure operational cooperation. Their first objective, curiously, was to agree on the division of their respective zones of operation rather than on cooperation (see Figure 1).Footnote ⁵³ On 15 December 1941, Ambassador Ōshima delivered a draft proposal to the German Foreign Minister, Joachim von Ribbentrop. The proposal considered the Indian Ocean as the nucleus of Axis combat cooperation. This vast sea (and the Asian continent in general) was divided into two zones: Japan was to control the area lying to the east of longitude 70º E, while Germany and Italy were to control the area lying to the west of it, although the proposal also stipulated that ‘each side may carry out operations across the above agreed boundary, according to situation’.Footnote ⁵⁴ The Indian subcontinent was supposed to fall into Japanese hands, but Ōshima, in a reception held in his honour by the Führer a day earlier, stated that ‘it will be most advantageous if Japan attacked India from the east and German troops threatened India from the west’.Footnote ⁵⁵

Figure 1 Japanese and German proposals for the division of their respective operational zones, December 1941. Source: Gerhard L. Weinberg, Visions of victory: the hopes of eight World War II leaders, Cambridge: Cambridge University Press, 2005, p. xxiv. Reproduced courtesy of Cambridge University Press.

Hitler responded positively to Ōshima’s grand strategy, mentioning plans for the advance of German troops into Iraq and Iran via the Caucasus in the spring of 1942, and in that way threatening India.Footnote ⁵⁶ Those plans, however, never materialized. In a similar vein, less than a year earlier, Italy had lost Italian Somaliland to Britain, and thereby its only hold in the Indian Ocean. It was thus the case that no Italian or German army unit would ever reach the Indian Ocean after December 1941. In the naval sphere the situation was different, however. Both the Regia Marina and the Kriegsmarine were in a better position to deploy their own units in the region, but the choice was limited. By then, their surface warships were on the weaker side and mostly relegated to defensive roles in their home waters. Thus inter-Axis combat cooperation had to rely exclusively on submarine warfare.

What made submarines such a devastating weapon during the two world wars was their capacity to sink merchant ships efficiently and almost clandestinely, and thereby to suffocate the supply lines of an entire nation. This quality made submarine warfare, both by the Kriegsmarine and the United States Navy, extremely successful in the Atlantic and the Pacific Oceans, respectively, and this was what made the inter-Axis cooperation in the Indian Ocean in 1943 so attractive. Submarines were especially suited for operation in this ocean, where until then the British Royal Navy had the upper hand, and where Allied cargo ships carrying vital materials from India and Persia and circumnavigating Africa could enter the Atlantic virtually undisturbed. Although the advantage of submarines in this arena was apparent, during the first two years of war in Europe, the military ties between Germany and Japan, much like their political relations, had been strained and distrustful. When a Japanese joint army and navy mission visited Berlin in December 1940 and submitted its procurement list of advanced German military technology, both high-ranking naval officers and industrialists expressed their strong opposition.Footnote ⁵⁷

The arrival of the I-30 in Lorient in August 1942 heralded the onset of a new and more intensive stage in German–Japanese military relations. This turning point was not the outcome of its brave voyage per se, but of a changing geopolitical situation – the German onslaught on the Soviet Union about a year earlier and the subsequent Japanese takeover of Southeast Asia – that facilitated the submarine’s departure in the first place. With the shutdown of the Trans-Siberian route, and even more so with the sudden Japanese appropriation of Europe’s Asian colonies, Germany needed Japan enough that it began to take the wish list of its Asian ally seriously. As optimism on the eastern front faded away, the need for Japan intensified. Any further Japanese action, either on land against the Soviet Union, or at sea against the Anglo-Saxon countries, was desirable. This was not necessarily the Kriegsmarine’s view, which initially did not support the Führer’s willingness to provide Japan with cutting-edge technology in return for its cooperation. Ironically, the Kriegsmarine’s initial opposition notwithstanding, the resulting flurry of military relations involved the participation of none other than members of the two navies.

The Kriegsmarine’s attitude towards cooperating with Japan did not change instantly. Despite Hitler’s insistence on compliance with the Japanese demands and on the departure of German blockade-runners to East Asia in the autumn of 1941, both navies were initially disappointed with the content and quality of the items the other party dispatched. By the time that the I-30 left for Europe, the IJN was still reluctant to reveal its advanced Type 95 oxygen-propelled torpedoes. Consequently, these torpedoes were removed from the submarine and replaced with fourteen older-model torpedoes. Apart from a small amount of raw materials, the I-30 carried the blueprints of the Type 91 aerial torpedo.Footnote ⁵⁸ This supply of armaments thus supplemented an earlier stock of Japanese torpedoes provided to the Kriegsmarine.Footnote ⁵⁹ Before its voyage back on 22 August, the I-30 was loaded with a number of advanced German weapon systems, including guns, bombs, torpedoes, and radar.Footnote ⁶⁰ The homeward voyage was faster, and, little more than six weeks later, the submarine entered Penang for refuelling. Five days later, it hit a British mine off Singapore and began to sink rapidly. Most of the crew was saved, along with some of the equipment, but not the radar. This disaster did not further impede the exchange of military technology, however. In January 1943, and against the view of the Kriegsmarine, Hitler decided to present Japan with two advanced Type IXC U-boats, hoping that the IJN could improve its submarine technology, escalate its warfare against Allied shipping, and tip the war in favour of the Axis powers.Footnote ⁶¹

The early summer of 1943 turned out to be a honeymoon in German–Japanese naval relations, which mostly materialized in the Indian Ocean and in a few Southeast Asian ports. Hitler’s first offering, the submarine U-511, left for Penang on 10 May 1943, carrying the Japanese naval attaché in Berlin, Vice Admiral Nomura Naokuni. Reaching Kure, Japan, on 16 September 1943, it was handed to the IJN and renamed RO-500, while the German crew returned to Penang.Footnote ⁶² The second submarine, U-1224, was initially employed as a training ship for Japanese crews, and was eventually transferred into Japanese service on 15 February 1944, being renamed RO-501. During its voyage from Europe to Penang, it was sunk in the Atlantic Ocean on 13 May 1944.Footnote ⁶³ A month earlier, the Japanese submarine I-8 had entered Brest, France, with a load of tin, as well as two blueprints of the once highly classified Type 95 submarine torpedo.Footnote ⁶⁴ In late 1943, two more Japanese submarines reached Europe and returned to Japan.Footnote ⁶⁵ The cargo submarine I-52 was the final Japanese vessel to carry out such a mission. Leaving Japan on 22 March 1944 with 2 tons of gold, it stopped over in Singapore where it was further loaded with 228 tons of tin, tungsten, and molybdenum, 54 tons of raw rubber, and 3 tons of quinine. This voyage was never completed, as the I-52 was sunk by an American bomber on 23 June 1944 while rendezvousing with a German submarine in the mid Atlantic.Footnote ⁶⁶

The importance of these technological exchanges notwithstanding, it was combat activity that made the Indian Ocean a true hub of Japanese–German cooperation. As before, Ambassador Ōshima played a major role in facilitating more intensive relations. On 11 December 1942, he met with Foreign Minister Ribbentrop to discuss the situation in Stalingrad. Dismissing the situation as no more than a tactical setback, Ribbentrop urged the ambassador to persuade Japan to launch a naval offensive in the Indian Ocean. He insisted that fulfilling this wish of Hitler’s was more crucial than a Japanese attack on the far eastern Soviet border.Footnote ⁶⁷ By then, the Indian Ocean was not an unknown territory to the Japanese Imperial Navy. Earlier, in late March 1942, Japanese naval forces had ventured out into this very ocean, when the Southern Expeditionary Fleet raided Allied convoys off the east coast of India and bombarded coastal installations near Calcutta, while a carrier strike force under the command of Vice Admiral Nagumo Chūichi raided Colombo and Trincomalee.Footnote ⁶⁸

Japanese submarines, too, had operated in the Indian Ocean. In April 1942, for example, a five-vessel unit left Penang for a hunting mission along the East African coast. What started as an uneventful cruise came to an unexpected peak when this force, using midget submarines, damaged the old British battleship HMS Ramillies and sank a tanker in the harbour of Diego-Suarez, Madagascar.Footnote ⁶⁹ In June of the same year, however, Nagumo’s strike force lost four fleet carriers in the Battle of Midway, in what became a stinging blow to the IJN’s pride and morale. Nevertheless, between August and November 1942, the five Japanese submarines operating in the Indian Ocean succeeded in sinking ten cargo ships totalling close to 60,000 tons, whereas in early 1943 the three remaining submarines in the arena sank eight cargo ships.Footnote ⁷⁰ Hence, although Ribbentrop urged Ōshima to act, the temporary diversion of substantial Japanese naval forces from the Indian Ocean became virtually indefinite. From this point onwards, Germany had to take the lead if it wanted to fend off Allied shipping in the Indian Ocean.

German submarines did operate in the Indian Ocean before this time, but they were few in number and had no permanent base, relying instead on provisions provided by auxiliary cruisers and supply ships. This state of affairs came to an end, however, on 30 November 1942, when the tanker Altmark and the auxiliary cruiser Thor were set ablaze in Yokohama. As early as February 1942, the then Vice Admiral Dönitz, commander of Germany’s submarines, had contemplated the use of a local port in Southeast Asia as a naval base for his submarines.Footnote ⁷¹ Almost a year later, in early 1943, it was the IJN’s turn to make an offer and launch a new course of inter-Axis naval collaboration in the Indian Ocean and Southeast Asia. The first step in this direction occurred on 26–27 April 1943, when the German U-boat U-180 and the Japanese submarine I-29 met at a prearranged point south-east of Madagascar and exchanged military technology and passengers. While the former carried blueprints for jet engines and V-2 rockets, as well as the Indian nationalist Subhas Chandra Bose (see Figure 2), the latter brought plans for advanced torpedoes and two IJN personnel, who were bound for Germany in order to observe U-boat construction.Footnote ⁷²

Figure 2 Subhas Chandra Bose, his adjutant (on his right), and the crew of the Imperial Japanese Navy submarine I-29, on board the submarine. Source: Wikimedia Commons, https://commons.wikimedia.org/wiki/File:19430428_japanese_submarine_crew_i-29.png (consulted 25 March 2017).

Another milestone in inter-Axis naval relations transpired two months later, when Penang became the home port for an embryonic submarine unit known as the Monsoon Group (Gruppe Monsun).Footnote ⁷³ Although the port of Sabang, off the north-western tip of Sumatra, was offered at first, Penang was eventually made the Kriegsmarine’s main naval base in the Indian Ocean. This former British seaplane station and wartime base of the IJN’s 8th submarine group was chosen for its strategic location and available facilities. Thereafter, it would serve as a point of departure for submarines hunting for Allied shipping in the Indian Ocean, and for submarines transporting raw materials and military technology to either Europe or Japan’s home islands.

Apart from Penang and a terminal port in Kobe, Japan, the Monsoon Group was to frequent and rely on several additional bases in the region, chiefly Batavia (present-day Jakarta) and Surabaya (a large submarine base previously belonging to the Royal Netherlands Navy), both on the island of Java, and the former British Royal Navy base in Singapore on the southernmost tip of the Malay Peninsula (see Figure 3). These bases were largely self-supporting, and the German crews, often bored and homesick, maintained rather limited ties with the local Japanese authorities, and suffered from a high rate of malaria.Footnote ⁷⁴ Penang was the exception, but relations there were not warm either, as friction with the local Japanese authorities over fuel, supply, and overall authority was rife.Footnote ⁷⁵

Figure 3 The Indian Ocean and Southeast Asia: Inter-Axis military cooperation, 1942–1945. The map shows more than 90% of the Allied cargo ships sunk in these waters. Most of the U-boats were sunk in the Atlantic Ocean, on their way to or from Southeast Asia, and so do not appear on this map. The location of the sunken cargo ships and submarines was determined using the following web resources: ‘Location of shipwrecks by year’, Wikipedia, https://en.wikipedia.org/wiki/Category:Lists_of_shipwrecks_by_year; ‘Ships hit by U-boats in WWII’, Uboat.net, http://uboat.net/allies/merchants/; ‘U-boat fates’, Uboat.net, http://uboat.net/fates/; ‘Japanese submarines lost during World War II’, Wikipedia, https://en.wikipedia.org/wiki/Category:Japanese_submarines_lost_during_World_War_II (all consulted 31 March 2017). Source: Rotem Kowner.

During the final two years of the war, these Southeast Asian ports and the adjacent waters of the Indian Ocean were the only arena in which the three Axis powers operated together.Footnote ⁷⁶ Of the navies of the two European Axis powers, the Kriegsmarine was indisputably the leader. Its first submarine, the U-511, arrived in Penang on 17 July 1943 and the second one, the U-178, on 27 August. Commander Wilhelm Dommes, the latter’s captain, became the commanding officer of the fledging local submarine unit, which operated in the region until Germany’s surrender almost two years later. The number of submarines operating in the arena increased gradually, given that attacks on other submarines were strictly forbidden in order to avoid incidents between these vessels. On the day that Germany surrendered, six German and ex-Italian submarines remained in East Asian ports (the U-219 and U-195 in Batavia, the U-862 and U-181 in Singapore, and the UIT-24 and UIT-25 in Kobe). They were all taken over by the IJN and used for a further three months, until Japan’s surrender, with an unremarkable record of service during this time.

By May 1945, the Kriegsmarine had assigned no fewer than fifty-seven submarines to the Indian Ocean, some dispatched more than once. Although not all arrived in Southeast Asian ports and many were sunk, their contribution should not be underestimated. Altogether, these submarines’ patrols, mostly off the south-eastern coasts of Africa and Madagascar, and around the southern coasts of India, succeeded in sinking 151 Allied ships and carrying 935,000 tons of vital raw materials and supplies.Footnote ⁷⁷ Incredibly, these figures are only slightly lower than those achieved anywhere by the entire IJN force of 171 fleet submarines throughout the war.Footnote ⁷⁸

Ideological kinship: anti-Semitic policies

The unique inter-Axis nexus in the Indian Ocean was also expressed in the willingness of the Japanese naval authorities to adopt special measures upon German instigation. On 18 January 1943, for example, the crew of the IJN cruiser Tone massacred sixty-five survivors of the British SS Behar in the Indian Ocean. After the war, eight commanding officers of warships involved in that and other massacres were convicted of war crimes. In their defence they insisted that they were merely following their superiors’ orders, but the highest authority tried, Vice Admiral Nakazawa Tasuku, maintained that the orders had come from the Germans.Footnote ⁷⁹ Indeed, the incident dates back to early 1942, when Hitler told Ōshima that the Axis Powers should kill captured crews of Allied merchant ships. On 20 March 1943, the chief of staff of the Japanese Sixth Fleet issued an additional massacre order to the submarines operating in the Indian Ocean, which they followed for the first time in December, culminating in the massacre of the survivors of the Dutch SS Tjisalak and the American SS Jean Nicolet on 26 March and 2 July 1944, respectively, by the crew of the I-8 submarine.Footnote ⁸⁰

The Japanese–German ties in the region also manifested at a deeper ideological level, non-existent elsewhere, that materialized in special measures against the local Jewish population. Prejudice and discrimination towards Jews, a cornerstone of Nazi ideology, surfaced in the profuse use of anti-Semitic propaganda and in the imposition of exceptional measures against Jewish communities in Southeast Asia. Historically speaking, the ‘Jewish problem’ emerged in Japan at a rather late point.Footnote ⁸¹ It began to bud in the early 1920s, when Japanese officers stationed in Siberia came across anti-Semitic literature and Japanese diplomats faced a torrent of reports and queries on Jewish issues. That decade also witnessed the publication of blatantly anti-Semitic literature in Japan, much of it translated from European sources.Footnote ⁸² With Hitler’s rise to power, a growing number of Japanese Army officers, radicals, intellectuals, and ordinary Germanophiles began to adhere to Nazi ideology and give credence to its anti-Jewish propaganda.Footnote ⁸³

By the late 1930s, the Japanese government was still vacillating between the desire to exploit the economic power of international Jewry for the sake of developing Manchuria, and the anti-Jewish negative attitudes precipitated by its Axis partners.Footnote ⁸⁴ In the context of isolationist anxieties in Japan, however, the Führer’s view that the Jew ‘now incites the nations against Japan as once he did against Germany’ seemed more than relevant.Footnote ⁸⁵ Jews were now becoming a target of scapegoating. During 1943, Southeast Asia witnessed a rise in anti-Semitic propaganda that was greater in intensity than in any other place in the Japanese empire. This seems partly to have been due to German incitement and the intensive inter-Axis collaboration that took place in the region. Although the Jewish population in the entire region was trifling (about 5,000 people, living mainly in Batavia, Surabaya, Singapore, and Manila), it did not take long for it to become the target of fears and repugnant propaganda.Footnote ⁸⁶

In Southeast Asia, and in Java in particular, the Japanese attraction to anti-Semitic ideology tended to be associated with the exchange of raw materials and the consolidation of naval cooperation with Germany. The first half of 1943 saw intensive German activity in the region, including visits by high-ranking officials.Footnote ⁸⁷ At the same time, the Japanese authorities in Java, the most populated area in the region, began to run an anti-Semitic campaign based on German propaganda. The harbinger of this campaign was Major Murase Mitsuo, the deputy head of the Sixteenth Army’s Kempeitai (the military police of the Imperial Japanese Army). His anti-Semitic speech to propaganda officials in Batavia on 4 April 1943 was echoed in the same month by pronouncements of similar content in the local Indonesian press.Footnote ⁸⁸ This rhetoric was not necessarily directed against members of the local Jewish communities, who by that point were largely incarcerated in either POW camps or internment camps. Instead, the campaign targeted ‘Jewish world control’ while addressing the local Muslim population, whose economic situation was deteriorating rather than improving under Japanese rule.

Germany’s ideological impact was exerted by its representatives both in Tokyo and in the ex-colonies. Among those advocating anti-Jewish policy in Southeast Asia, the most high-ranking figure was probably state councillor Wohlthat, whose personal background may also account for this aspect of his activities. As a former director of Göring’s Four-Year Plan, he had dealt, inter alia, with programmes for the resettlement of German Jews (notably the Madagascar Plan and the Rublee–Wohlthat Agreement) and the utilization of their property.Footnote ⁸⁹ Considering these earlier assignments, it is hardly surprising that the state of the local Jews was also discussed during visits by German officials to Java. Owing to the limited number of Jews and to the fact that most of them had already been incarcerated, the Jewish problem was obviously a minor issue in the German itinerary. Nonetheless, their treatment was not ignored during the negotiations and the eventual economic settlement. (It should be noted here that the destruction of Europe’s Jewry was in full swing at the time of Wohlthat’s visit, and the Jews of the Netherlands, where Wohlthat had served earlier, were certainly no exception.Footnote ⁹⁰ )

Other Nazi officials in East Asia had been pursuing the very same policy of persecution since the early 1940s, although they had to resort to persuasion for lack of soldiers. During the entire course of the war, they urged Japan to treat the Jews in any of its territories in a harsher manner and preferably eliminate them.Footnote ⁹¹ The most notorious such case is that of Shanghai, where German officials were active in exhorting and inciting the Japanese to pursue an anti-Semitic policy against some 27,000 Jews, mostly refugees from central Europe, who had swarmed into the city before the outbreak of the war in Asia.Footnote ⁹² Although the extent to which German instigation was decisive remains uncertain, the Japanese authorities in the city were evidently responsive to these pressures.Footnote ⁹³ In an unprecedented act carried out on 18 May 1943, the authorities forced some 20,000 ‘stateless’ Jews to relocate into a ‘designated area for stateless refugees’ (Japanese shitei chiku, but often referred to as a ‘ghetto’), while leaving free several thousand other Jews, mainly those of Middle Eastern (‘Baghdadi’) and Russian origins.Footnote ⁹⁴

In Southeast Asia, and in Java in particular, Nazi ideological pressure was even more effective. In the summer of 1943, in fact, German officials made use of an additional pretext for persecuting the Jews residing in Java and the Malay Peninsula.Footnote ⁹⁵ With the establishment of German naval bases in this region, both Baghdadis and Jewish citizens of neutral countries, who, like many Eurasians, were not interned, could theoretically constitute a security problem. By gathering sensitive information about the movement of German vessels and transmitting it to the Allies, they were capable of endangering the entire German–Japanese economic-technological exchange and military cooperation apparatus.Footnote ⁹⁶ Aware of the risk, in August 1943 the Kempeitai arrested a ring of Eurasians suspected of reporting the movement of Navy units in Surabaya, and a month later detained some 350 Jews, along with a number of Dutch freemasons and missionaries.Footnote ⁹⁷ But with the scale of Berlin’s interests in Southeast Asia growing, and following Wohlthat’s involvement, the eventual Japanese response with regard to the local Jews was far-reaching. In mid August 1943, shortly after the visit by German officials and the arrival of the first German submarine at its new base in Penang, the military authorities in Java completed the internment of the entire Jewish community on the island (and practically in the archipelago as a whole).Footnote ⁹⁸ Here, unlike any other place in the Japanese empire, they arrested all those registered as Jews, including members of two groups that were not directly associated with the Dutch regime: Jews of Axis nationality and those of Baghdadi ancestry. In addition, the Japanese authorities began to segregate Jewish detainees from non-Jewish detainees.Footnote ⁹⁹

The relatively large community in Singapore, where about 850 Jews of mostly Baghdadi origin had lived before the war, was not spared either. On 5 April 1943, the Kempeitai arrested as many as 103 men, who made up about one-sixth of the wartime community. The remaining members, including women and children, were left unharmed but were eventually arrested too, along with a small number of Eurasians, on 25 March 1945.Footnote ¹⁰⁰ In contrast, the Philippine Jewish community was not arrested en masse during the war, despite a number of incidents of anti-Semitic propaganda, deliberate abuse, and occasional visits by German officials in Manila from January 1943 onwards.Footnote ¹⁰¹ Comprising some 2,500 members on the eve of the war, of whom a little more than half were refugees from Germany and Austria, the community was not treated in a uniform fashion. The Japanese authorities did incarcerate about 250 members of the community who held Allied citizenship, much like other ‘enemy alien’ civilians, but tended not to distinguish between German Jews and other German nationals. All things considered, one may indeed attribute the fate of this community to the Philippines’ location outside the nucleus of inter-Axis collaboration.

All in all, circumstantial evidence and testimonies indicate that Nazi officials instigated, and successfully pressurized the Japanese government and local authorities to mete out, harsher treatment to the Jewish communities in Southeast Asia. There were undoubtedly additional motives for this Japanese conduct stemming from local circumstances.Footnote ¹⁰² But the fact that such pressure was not as effective in any other part of the Japanese empire tells us much about the scale and potency of the broad inter-Axis cooperation in this region.

The Indian Ocean as the nucleus of inter-Axis cooperation: motives and implications

During much of the war, independent policies, isolated theatres, the departmentalization of technological knowledge, and divergent military objectives characterized the relations of the European and Asian Axis powers. In mid 1943, this situation changed rapidly when Southeast Asia became the only place where Japan, Germany, and Italy ever collaborated militarily. This cooperation was a far cry from any fantasy that Hitler held of joint rule of the world, but it was the closest approximation to his wartime vision of a global strategy. The inter-Axis cooperation in the Indian Ocean developed cautiously and in a piecemeal manner. While geopolitical motivations were predominant, the Japanese consent for the deployment of German U-boats in the Indian Ocean, and Southeast Asian ports in particular, was also spurred by the pursuit of advanced technology, whereas Germany’s willingness to share its technology stemmed at first from the need for raw materials. Military collaboration emerged relatively late; ideological synergy came last and remained on the back burner.

The Japanese wartime collaboration with Germany – and, to a much lesser extent, with Italy too – was mainly focused on the area around the Straits of Malacca and the Java Sea. It was not, however, by mere chance that this region became the nucleus of unprecedentedly intensive Axis cooperation. Located at the westernmost part of the Japanese empire, more than 6,000 kilometres from Tokyo, this region monopolized a vast supply of vital raw materials and controlled crucial sea lanes separating the Indian and Pacific Oceans. This liminal zone on the edge of their empires allowed the two leading Axis powers to overcome their mutual suspicion and so accomplish at least some degree of collaboration.

In such a remote zone only naval forces could operate easily. No wonder, then, that naval needs gradually took control of the cooperation, although both sides remained uncertain about it for quite some time. In the late 1930s, in fact, the IJN was tepid if not hostile to an alliance with Germany, fearing that it might hasten a conflict with the Soviet Union.Footnote ¹⁰³ Even before its surprise military strike on Pearl Harbor on 7 December 1941, leaders of this service were concerned about the possibility of the Battle of the Atlantic entangling the Kriegsmarine in a war with the United States Navy.Footnote ¹⁰⁴ Nonetheless, both navies regarded the Anglo-Saxon naval forces as their main enemy and opposed, to varying degrees, a war with the Soviet Union. Apart from this geopolitical vision, they also shared an inter-service rivalry with the Army (and in Germany with the Luftwaffe too), which resulted in a struggle for budgets, manpower, and materials.Footnote ¹⁰⁵ Thus, the combat cooperation in the Indian Ocean and the exchange of military technology was also used to reinforce the position of each force in its domestic rivalry, and to offset budget constraints.Footnote ¹⁰⁶

The Italian participation in this inter-Axis cooperation was, however, little more than symbolic. Indeed, after losing the last grip on its East African colonies in November 1941, Italy’s naval and imperial aspirations became necessarily restricted to the Mediterranean Sea, where for a while it did well in keeping the Royal Navy busy and even weakened.Footnote ¹⁰⁷ Nonetheless, 1943 was a year of defeats. In May, the Allies finally overpowered the Axis armies in North Africa; two months later, on 10 July, a combined force of American and British Commonwealth troops landed in Sicily. By the time that the Japanese–German military cooperation in the Indian Ocean showed signs of consolidation, Mussolini’s regime was fighting for its last breath, and was neither interested nor able to invest elsewhere. With the Italian leader’s downfall in September 1943, the Tripartite Alliance became an alliance of two, although a limited number of Italian submarine crews kept fighting in the region until the end of the war.

Submarines became the means and raison d’être of Axis collaboration in the Indian Ocean. This is intriguing since no other type of warship embodied the differences between the two navies with greater clarity. Whereas the Kriegsmarine excelled in producing and operating submarines, the IJN was utterly deficient. This contrast, however, was not new. Within less than two decades of its great victory over Russia in 1905, the IJN had advanced spectacularly, to the point of becoming the world’s third largest navy in the interwar era. But size and power were not the sole determinants of naval excellence. Whereas in 1905 the IJN relied on British-constructed warships, less than two decades later it boasted the indigenous production of just about any kind of warship. Submarines, however, remained the Japanese Achilles’ heel, and throughout the first decade of the interwar era Japan relied on German technology and expertise to address this deficiency.Footnote ¹⁰⁸

In December 1941, Japan led naval development in several aspects, such as carrier tactics, carrier-borne naval aviation, and torpedoes, but not in submarine warfare. The IJN possessed sixty-five fleet submarines of various qualities and modernity, but none was considered without peer. Hence, when a Japanese legation under Vice Admiral Nomura arrived in Berlin in 1941 to explore various options for military exchange, submarine construction was the focal point of its naval interest.Footnote ¹⁰⁹ That said, in hindsight the primary problem with the Japanese submarines was not necessarily technological but rather a matter of doctrine. Despite the spectacular use of U-boats in the First World War and the first years of the Second World War, the IJN stubbornly ‘failed to conceive of its submarines as commerce raiders’.Footnote ¹¹⁰ Admittedly, Japanese naval theorists on the eve of the war had offered several persuasive arguments advocating the use of submarines for other purposes, but by 1943 it was evident that their initial plans for a decisive battle against an American force of battleships were anachronistic.Footnote ¹¹¹ By then, the deployment of U-boats in the Indian Ocean not only facilitated the concentration of IJN surface ships in the Pacific arena, but also provided a window into recent German submarine technology and tactics.

A critical analysis of the Axis Powers’ cooperation in the Indian Ocean suggests that it played a limited role within their war efforts. Italy gained almost nothing from the cooperation, since it was too brief and, apart from limited access to certain raw materials, was overshadowed completely by the military crisis at home. Japan certainly gained more, but eventually the raw materials and cutting-edge military technology that it received from Germany were of little use. Crucially, at this late stage of the war, the German assistance exerted almost no impact on Japan’s capacity to defend its shipping against American submarines and to shield its home islands from strategic bombings. Moreover, the Kriegsmarine’s use of Southeast Asian bases hardly contributed to the Japanese war effort, since it targeted supply to Britain’s home islands with little relevance to the Asian Pacific theatre. What Japan needed was assistance in anti-submarine warfare and doctrinal change in its own use of submarines against Allied shipping in the Pacific, but in these two aspects the German presence contributed nothing.

Germany was the party that benefited the most from the inter-Axis Indian Ocean cooperation. This explains its willingness to risk tens of U-boats far from their Atlantic comfort zone, and to share some of its most classified technological innovations with a seemingly undependable ally. Owing to the submarines’ eventual debacle in cargo missions and the insubstantial use of Japanese military technology, the most important aspect of this collaboration for Germany was the use of Asian ports as submarine bases. The U-boats’ success in sinking close to one million tons of vital raw materials in the Indian Ocean and adjacent waters was a spectacular achievement, no doubt, but a future analysis may determine whether these submarines could not have contributed equally or even more significantly had they stayed in the Atlantic Ocean. The activity of the U-boats in the region could hardly be considered collaboration. While the Japanese provided the bases, fuel, and provisions, by mid 1943 it was only German vessels that operated in this vast ocean. Similarly, it was Hitler who took personal interest in this activity, whereas in Japan the maintenance of the alliance and the consequent cooperation remained under the auspices of Ambassador Ōshima in Berlin. In fact, throughout Japan’s four-year war in the Pacific, not one Japanese leader ever met with a German or Italian counterpart, and no high-level coordination ever took place between Japan and its European allies. In such circumstances, even the limited accomplishments of the Indian Ocean cooperation can be regarded as a triumph.

The historian Bernd Martin has observed that, overall, the Axis attempts at cooperation ‘were successful only when they were hopelessly engaged in a strategic defensive’.Footnote ¹¹² Indeed, by 1943, Hitler’s vision of inter-Axis cooperation and joint rule was a lost cause, since each power desired things the other could not provide: Germany wanted Japan to wage war against the Soviet Union, whereas Japan needed Germany’s help in its struggle against the United States. Such collaboration was so unrealistic that neither of the two nations discussed it explicitly. Instead, they compromised on a limited degree of cooperation, which was expected to serve as a catalyst for the existing exchange of indispensable raw materials and cutting-edge military technology. Both parties were fully aware that its strategic importance was restricted and far from crucial. And yet, even the limited results of the inter-Axis cooperation in the Indian Ocean tell us a great deal about the horrendous potential it could have had, had Japan and Germany overcome their mutual suspicions and coordinated their efforts two or three years earlier.