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Yes, the Germans and the Japanese did collaborate. No, it didn’t do much good.

The USS Sea south of Borneo the afternoon of April 23, 1945. The submarine’s skipper, Lieutenant Commander Herman E. Miller, had come to trust the uncannily accurate intelligence headquarters had been sending, Besugo was running submerged in the Java so as he pursued his latest intercept mission it did not surprise him to see an enemy sub—as predicted—on the surface. None of Miller’s veteran crew recognized the silhouette, but they could not mistake the vessel’s markings: a large red disc centered in a white rectangle on either side of the conning tower, and an enormous rising sun battle flag.

Miller spent 13 minutes maneuvering his sub into firing position. From 1,500 yards he fanned a six-torpedo spread. At impact his target vanished.When the Besugo surfaced, crewmen encountered a constellation of bubbles, the beginnings of an oil slick, and one man, badly injured but alive—though not at all who they expected. The new prisoner of war identified himself as Obersteuermann Karl Wisniewski, and said that the Americans had just sunk U-183.

The sequence that brought a U-boat to grief off Asia in the last days of the Reich began as a collaboration between Germany and Japan—a troubled arrangement that the Axis nations approached less as allies sharing strategic objectives than as criminals sharing burglar’s tools and booty. Japan sought advanced German weapons to turn against the Americans; Germany wanted raw materials Japan had looted. Neither trusted the other. By the time this pact of steel burned out, all that remained was a handful of U-boat sailors battling miserable odds far from home—spear-carriers implementing a policy that submarine warfare historian Allison W. Saville declared “misconceived, misdirected, and tragically wasteful.”


GERMAN PROPAGANDA PORTRAYED THE AXIS as a front united by treaties signed in 1936–37 and reinforced in 1942, but the signatories—Germany, Italy, and Japan—honored the terms they set only when it suited them or when forced. Still, powerful figures in Tokyo and Berlin saw sufficient shared interests— a “common destiny” was how one put it—to try to make the partnership practical, especially once both main Axis war economies were roaring in 1942. Japan was fencing off its conquests against the gathering American offensive; Germany was not only fighting in the Soviet Union but facing the wane of the “Happy Time,” as Reich submariners dubbed 1940–41, when U-boats ravaged Allied convoys in the Atlantic.

At the war’s start, the Japanese dismissed U-boats as puny, while the Germans thought Japanese subs too large and clumsy for combat. These opinions reflected contrasting underwater doctrines. Japan’s combined fleet concept yoked subs to broader Imperial Navy missions (see “Sundown at Torpedo Junction,” January/February 2013), so Japanese submarines were generally of massive displacement, designed to accommodate everything from battle to resupply to launching exotic weapons, with disruption of enemy commerce a secondary target.

The German navy’s primary job was disrupting commerce, and early on Admiral Karl Dönitz made tonnage sunk the sole criterion for U-boat success. Destroy freighters and tankers faster than the Allies could replace them, with acceptable U-boat losses, and Germany would win, Dönitz reasoned. “As long as opportunity to sink ships in the Atlantic existed I…refrained from accepting the Japanese offers [to collaborate],” he wrote in his 1958 memoir. But once the tide began to turn he changed his mind about working with Japan—though not in public. Dönitz’s 500-page memoir devotes only 42 lines to the subject.

By the end of 1941, U-boats had sunk more than 4.8 million tons of Allied shipping, but as 1942 advanced so did Allied defensive technology and tactics. Coupled with cracking German codes, these improvements were making the North Atlantic perilous for U-boats, forcing Dönitz to dispatch his submariners farther afield. Once he replaced his 770-ton medium-range Type VII boats with 1,050-ton Type IXs that could sail farther and stay out longer, Dönitz began to see the Indian Ocean as a combat arena in which Allied vessels supplying forces in Egypt, India, and Burma offered tempting targets. In time the Kriegsmarine extended its reach to the Pacific, where even Italy, by far the Axis junior partner, would wind up placing a few subs.

In 1942 Germany and Japan set up a trade exchange the Japanese called Yanagi (“Willow”). The Germans needed tin, rubber, tungsten, manganese ore, and other materials scarce in Europe but plentiful in regions Japan now ruled. Initially the Japanese wanted mercury, aluminum, steel, lead, and other highly refined materials to make versions of German technologies and homegrown weapons. As the fortunes of war changed, the Japanese shopping list tilted away from raw materials and toward ready-to-use munitions. In Willow’s first year some 18 surface vessels traveled between French ports along the Bay of Biscay and the Far East. Of those, 15 ships eluded the Anglo-American blockade to deliver approximately 65,000 tons of goods, enough to call the exchange operation a success.

In June 1942, Japanese submarine I-30 was dispatched from the Indian Ocean off Madagascar to the Kriegsmarine sub pens at Lorient, France, a voyage of nearly 18,000 miles from Kure on Japan’s southern coast. The crew brought news of impressive scores off east Africa. There, with other Imperial subs stalking ahead of an aircraft carrier raiding force, the I-30 had enjoyed rare permission to go after Allied supply vessels. The Japanese brought blueprints for an aerial torpedo and, for German electrical systems, 3,300 pounds of mica and 1,452 pounds of shellac. The visitors from the East enjoyed ample time to relax in Lorient, where some Japanese and German submariners autographed the roof beams in taverns.


THAT MONTH DÖNITZ DISPATCHED the first of two U-boat packs to prowl off east Africa. The first, code-named Eisbär (“Polar Bear”), sailed October to December 1942 and destroyed 216,164 tons of shipping. The second, Seehund (“Seal”), had more modest results in February–March 1943.

These forays encouraged Dönitz to send more subs east, and to expand beyond attacking. In February 1943, U-180 departed Germany on a special mission. Aboard was Indian nationalist Subhas Chandra Bose; he had broken out of jail in Calcutta, fled overland to Germany, lived for two years in Berlin, and now wanted Japan to help drive the British from India. Several hundred miles south of Madagascar, the U-boat met a Japanese submarine carrying two Imperial Navy sub specialists. The vessels swapped passengers and cargoes. U-180 returned to France on July 3 with the Japanese technicians and a load of Japanese weapons including a gun barrel and ammunition, 1,000 pounds of dispatches from the German embassy, and two tons of gold ingots to fund Japanese diplomatic activities in Europe.

After months of vexing negotiations, in April 1943 Japan agreed to provide Germany with bases in the East. The Japanese had not had an epiphany about Axis brotherhood: the Pacific War was straining their navy, and they were happy to let the Kriegsmarine set up shop if the Germans would take over Indian Ocean patrols. Dönitz recognized those waters as a last unprotected hunting ground for his wolf packs. A force designated Gruppe Monsun would operate from Japan’s westernmost naval station—on the island of Penang, off northwest Malaysia. A pier at George Town Harbor would become U-Stützpunkt Paul, the Kriegsmarine’s first and primary Pacific sub base. The pier could dock five U-boats and was served by rail spurs leading to machine and maintenance shops. Eventually 26 work sheds, including facilities with equipment to balance torpedoes for accuracy, adjoined the pier. Safe from Allied attacks, U-boat crews could dock their boats in the open air—unlike at bases in France, where the threat of Allied bombs forced subs to shelter in concrete-roofed pens.

Another transfer began on May 10, 1943, when U-511 sailed from Lorient carrying three German technicians plus mercury, a 3,000-horsepower Daimler Benz engine, and blueprints for a Type IX U-boat, which due to shortages was as close as the Kriegsmarine would come to the standard Japanese I-boat in size and range. The sub itself was a gift from Adolf Hitler to Hideki Tojo. U-511 stopped briefly on July 15 at Panang. From there, the U-boat sailed 3,000 miles to Kobe, Japan, to be recommissioned as the Imperial Japanese Navy’s RO-500. The crew of U-511 returned to Penang for duty as a standing reserve, along with technicians from other arriving Monsun subs.

Except for the conviviality between German and Japanese sailors at George Town’s harbor bars, Axis interactions at Penang tended to illustrate the old saw about twains not meeting. The Japanese generally left administration of conquered regions to the victorious service, so the Germans often faced Imperial Army hostility toward the navy—any navy. In one instance, after struggling into the harbor during a heavy storm, U-196’s captain tied up his boat at the first available pier. “But to our surprise,” an officer recorded, “we saw a Japanese army soldier go calmly to the bollard and unhook the line.” The U-boat crew had made the unforgivable mistake of docking at an army pier without permission.

War had made the cautious Japanese even more wary, leading to such constraints as prohibitions on the Germans at Penang independently contacting Berlin. “We could make our own messages and encode them, but we still had to use their transmitters,” recalled an officer who served aboard U-219. “We received from Dönitz directly, but not the other way around.”

Culture proved a constant stumbling block on both sides of the globe. German condescension toward Japanese gear led technicians to stick with their less reliable and shorter-range torpedoes rather than learn from the sophisticated liquid oxygen–powered Type 95, which could send an 890-pound warhead more than five miles. German and Japanese personnel might fraternize, but U-boat crews usually kept foreigners off their ships—a snub in Japanese sailors’ eyes. Japanese officers, accustomed to exchanging bows, bristled at receiving a standard service salute from a German. Dönitz worsened the muddle: failing to grasp how much the Japanese prized hierarchy, he let mid-grade German officers flounder at Penang amid status-obsessed and higher-ranking counterparts. “How strange these people were,” observed an officer on U-181. The two empires “really had no great sympathy for each other,” wrote Kurt Freiwald, who, after serving on Dönitz’s staff, commanded a U-boat in the Indian Ocean.

In the East the dysfunction went beyond the cultural to the practical. Japan could not provide critical supplies, forcing eastbound U-boats to dedicate scarce cargo space to spare parts and munitions. Rarely did Japanese lubricants and fuels meet Kriegsmarine specs. “The viscosity of the Asian oil was low,” engineer Dietrich Hille of U-181 recalled, and compared with thicker German mixtures it was so thin “you could easily check it with two fingers.”The long voyage took a toll on engines, Malaya’s climate played havoc with German torpedoes and electronics, and Penang was short on skilled laborers. Exhausted U-boat crews had to do their own repairs—if they could pry free tools and parts. Everything “must be begged in protracted discussions from Japanese stations,” an officer said. However, despite these aggravations and others like heat rash, skin infections, and the risk of malaria, U-boat men lived better than locals and the Japanese military, a pleasure that widened the divide.

Penang did have charms. The Japanese commandeered hotels and other facilities for German submariners. Men could occupy bungalows on palm-shaded streets dotted with soccer fields and bordered by beaches. Gardens sprouted potatoes, cabbage, and other European staples. Kriegsmariners frequented the Springtide and Elysee Hotels, the Penang Swimming Club, Mount Pleasure, Sakura Park, and Fraser’s Hill. A funicular climbed Penang Hill from George Town into the cooler highlands. At the Shanghai Hotel ballroom, if girls merely wanted to dance,“they got a certain kind of flower to wear,” U-861 commander Jürgen Oesten recalled. “But if they were willing to sleep with the boys then they wore a different kind of flower as a signal.”

“With unlimited freedom,” U-181 officer Otto Giese wrote, German submariners at Penang “felt as if they were in paradise.”


BUT PARADISE WAITED AT THE END of a fraught voyage. Simply to reach the eastern side of Africa, Monsun boats needed to refuel in waters closely watched by the Allies. As the first wave of 11 boats rolled out, their refueling tanker failed to break through the Bay of Biscay; the Allies sank its replacement, followed by one of two U-boats diverted from patrol to share their supply. Only five broke through to the Indian Ocean. There the crews chalked up a paucity of targets and the loss of another boat to bad luck, no more aware than the rest of the Kriegsmarine that the Allies had broken Germany’s naval codes. The inaugural Monsun patrols sank a disappointing 49,600 tons of shipping.

U-boats were hunting off east Africa at the end of August 1943 when a second Japanese submarine, I-8, reached Brest with manganese ore, other scarce metals, and sample Type 95 torpedoes. The I-8 also brought 50 Imperial Navy submariners for training, leavened with time off in Paris and other tourist spots. Following months of instruction and shakedown trials the Japanese sailors were to sail back with a brand new Type IX— with Dönitz’s grudging accession. He loathed parting with fresh boats, but Hitler insisted because the U-511 had had three patrols under its belt when given to Japan. Launched as U-1224 and designated RO-501 by the Imperial Navy, the new submarine departed Hamburg in March 1944. Allied watchers charted the boat’s progress and dispatched a hunter-killer group that sighted and sank it north of the Cape Verde Islands.

By the end of 1943, the Allies were sinking so many surface vessels that the exchange voyages went fully underwater. That November and December, Dönitz sent six more subs to join Gruppe Monsun in the Indian Ocean, where they scarcely fared better than his surface freighters. Only one U-boat reached the pen at Penang. Hectored by the Allies, the retreating Japanese were giving German submariners less grief. They agreed to set up a second stopover base at Batavia (now Jakarta), and to allow overhauls of German subs by Imperial Navy facilities at Singapore and on Java. U-boats needing battery charges had to sail to Kobe to join a queue at overburdened facilities at that Japanese port. Access to these harbors, which had accommodations similar to those at Penang, would be even more critical after March 1944, when Allied flyers sank the last German surface tanker in the Indian Ocean.

The Germans in Southeast Asia had been operating three fuelguzzling Italian cargo submarines when Italy surrendered in September 1943. The Japanese warily allowed them to keep shuttling around Southeast Asia, but distrust intensified as the war closed in on the Axis. As late as mid-April 1944 the Kriegsmarine was ordering U-boat captains approaching Penang to jettison unused acoustic torpedoes at sea to keep the top-secret tin fish away from Japanese eyes. The Imperial mission in Germany had thoroughly briefed Japan’s navy on the acoustic weapons, so all this precaution did was irk the Germans’ hosts.

France was the western terminus for most Axis sub exchanges, but after the Allies liberated the coastal areas following D-Day the operation moved to Kristiansand, a port in German-controlled Norway, extending the trip by several hundred miles.

To keep operating from Asian bases the persistent Dönitz had to unsnarl supply line kinks and balance pressure from Berlin and Tokyo to maintain the trade exchange, as well as endure punitive attrition. Of 16 U-boats to reach Penang or Batavia between 1943 and 1944, eight went on war patrol; four were lost. Two of the four surviving boats, along with the others already docked, were emptied and reloaded with tin, rubber, tungsten, quinine, and opium for the 90-day return trip and its perilous surface refuelings. Five boats made it to France past Allied sub-hunters along the route and even near Penang. Two Royal Navy sub flotillas based 1,300 miles away at Ceylon (now Sri Lanka) ranged at will, so unnerving U-boat skippers that on the final approach to George Town they habitually mustered most crewmen on deck wearing lifebelts, convinced a torpedo or mine would strike.


BY NOVEMBER 1944, JAPAN HAD CEASED offensive operations in the Indian Ocean. Many in the Kriegsmarine saw no point in continuing there, but Dönitz saw no choice: Hitler kept pushing the program, lobbied heavily by Ambassador Hiroshi Oshima and other Japanese higher-ups. Dönitz added cargo hauling to the U-boat mission, though a fighting sub could carry but a fraction of a surface freighter’s cargo and to accomplish even that had to be dismantled and reassembled in dry dock. Compounding the lunacy, Dönitz insisted that these heavily laden vessels hunt en route, inviting Allied attack.

In late 1944 Dönitz ordered an ambitious four-boat strike into Australian and New Zealand shipping routes, 5,000 miles from Batavia. To keep Japanese crews from attacking subs they might not recognize, the Germans informed the Imperial Navy. Regional commanders got word, encoded with ciphers the American military had cracked. On October 4 a Dutch sub ambushed U-168, on November 10 three American subs stalked and sank U-537, and unknown causes claimed U-196.

Only U-862, skippered by Commander Heinrich Timm, reached its hunting ground. Timm chased and lost a Greek freighter, and eight days later got a Liberty ship in his crosshairs. The SS Robert J. Walker fought back hard—its deck gunners detonated an incoming torpedo—but three fish hit, putting the Walker into the books as the only vessel sunk by a U-boat in the Pacific. Timm patrolled without further result until he received a recall order on January 17, 1945. En route back to Batavia he torpedoed the Liberty ship SS Peter Sylvester, whose February 6 demise marked the final sinking in the Indian Ocean of an Allied transport by the Axis.

By now B-29 crews based at Kharangpur, India, were bombing Penang. German subs shifted their base of operations to Batavia. Despite poor returns and immense and growing operational woes, trade continued between Germany and Japan, maintained by the increasingly desperate Japanese and the prideful Dönitz, who waited until April 15, 1945, to tell Japan’s senior military representative that further exchanges would be “a waste of time.” That day, a last U-boat departed Norway for the Far East with two Japanese aboard; when Germany surrendered on May 8, the U-234 was off Saint John’s, Newfoundland. Its crew surrendered there to the USS Sutton; the Japanese passengers killed themselves. Across Asia, the Japanese politely seized U-boats, absorbing them into the Imperial Navy but not deploying them, and interned their crews, often at Batavia where stores from the captured refrigerated steamer SS Nanking allowed the boatless submariners to live in modest comfort.


KARL DÖNITZ MAY HAVE BELIEVED his Indian Ocean adventure would tax the enemy and wound the Allies’ soft underbelly, but patrols there accomplished little and cost dearly. Dönitz sent 41 U-boats to join Gruppe Monsun: 22 were sunk en route, and another 9 were lost on patrol—31 U-boats sacrificed to sink 377,400 tons of Allied shipping.

The Japanese clearly came out ahead in the commodity trades. Experts and expertise from the Reich jump-started work on Japanese editions of the jet-propelled Me 262 and rocketpowered Me 163 fighters and other weapons such as integrated antiaircraft systems, while Germany got no more than 700 tons of raw materials—a fraction of the amount needed.

Through the treacherous voyages and patrols, discipline and esprit de corps kept U-boat mariners going. Assigned by his masters in Germany to refuel Japanese outposts, Captain Fritz Schneewind of U-183 agreed to fill his ballast tanks with oil at Batavia, making crash dives impossible. Schneewind could only run on the surface. To avoid friendly fire from Japanese units, he made sure his boat displayed clear Imperial markings. As always, Schneewind communicated in code—which Allied wizards read like a book. U-183 was two days into its mission when a torpedo from the USS Besugo killed Schneewind, his ship, and all of his crew except Obersteuermann Wisniewski.

German submariners operating in the East enjoyed idyllic interludes amid horrific times, but the supplies Japan provided were never enough to sustain the Nazi war machine, and the weapons and materiel Germany delivered were too few to make a difference for Japan. The sailors who died gave their lives for a policy born in the first rushes of victory, maintained for political rather than military reasons, and continued to the grim end out of desperation and hubris.


Originally published in the August 2013 issue of World War II. To subscribe, click here.