In 1940, Germany, Italy, and Japan signed the Triple Alliance Treaty, and the three focal points of World War II officially formed the Axis of the Three Kingdoms. As allies, although Germany and Japan are thousands of miles apart, for common purposes and ideals, the two sides still try to maintain strategic ties and military and scientific and technological exchanges, the most important of which is "willow transportation".
<h1 class="pgc-h-arrow-right" data-track="2" >What is "willow transport"? </h1>
Before the outbreak of the Soviet-German war, the Soviet Union maintained a friendly relationship with Germany and Japan on the "surface". At this time, Japan's contacts with Germany could be done magnificently through the Trans-Siberian Railway in the Soviet Union. For example, in March 1943, Japanese Foreign Minister Yosuke Matsuoka visited Germany and Italy through this route. The purpose of Matsuoka's visit was to confirm the possibility of a Soviet-German war and to complete the adjustment of Japanese-Soviet relations. Matsuoka then took a train along the Trans-Siberian Railway through Moscow to Berlin and Rome. On the way back, Matsuoka and Molotov signed the Treaty of Neutrality between Japan and the Soviet Union at the Kremlin.
In 1941, Germany invaded the Soviet Union, which led to the direct interruption of land communications between Japan and its European allies. In order to maintain the necessary strategic exchanges, there is only one choice between Japan and Germany and Italy, and that is to go all the way by sea. Due to the Allied blockade of the sea, and the fact that the Suez Canal had been controlled by the British, there was only one sea route left between Germany and Japan, which was quite expensive in time and labor, that is, from the port of the Bay of Biscay under German occupation, through the Atlantic Ocean, bypassing the Cape of Good Hope, passing through the Indian Ocean, and reaching Japan-controlled Singapore. With the collapse of the main fleet of the German and Japanese navies, this important task had to rely heavily on more concealed submarines to complete, and the Japanese "I"-type submarines naturally became the main force of this series of secret transport tasks due to their high displacement and long range.
In the German-Japanese submarine exchange, the operation from Germany to Japan is called "willow transport" (which is mainly the name of the Japanese side), and the transportation materials are mainly new weapons and their drawings, industrial products, and technical data; and the operation from Japan to Germany is called "anti-willow transportation", and the materials are mainly rare mineral deposits such as insect paint and mica urgently needed by Germany, plus Japan's advanced HNA technology.
< h1 class="pgc-h-arrow-right" data-track="6" > the maiden voyage of the "Willow Plan", and the I-30 successfully visited Germany. </h1>
In April 1942, the I-30 ocean-going submarine (Cruise B) of the 8th Submarine Squadron of the Japanese 1st Ship Squadron was cruising alone in the Indian Ocean, waiting for an opportunity to attack Allied ships. At this time, The Boat Elder Fujinobu was given the task of carrying out the "Yanagi" plan. The I-30 returned to Penang to load the supplies it needed to carry and headed straight for the European coast. After 2 and a half months of arduous sailing, cleverly dodging the tracking of British anti-submarine patrol aircraft, the I-30 sailed smoothly into the Bay of Biscay on the west coast of Spain. When Germany received the telegram from the I-30, it immediately sent 8 Junkers-88s and 4 destroyers to escort them. Soon the I-30 sailed into the Important German Submarine Base, the French port city of Lorient in the Mediterranean.
Marshal Raeder, commander-in-chief of the German Navy, shook hands with Captain Ito Shinobu of the I-30
The arrival of the I-30 excited the German high-level, including The Commander-in-Chief of the Navy, Admiral Raeder, the Commander of the Submarine Force, Admiral Dönitz, and the Japanese Naval Attaché to Germany, Tadao Yokoi, all came to Lorient to welcome the arrival of the I-30, and even Hitler made an exception to receive Ito Shinobu himself and awarded him the Iron Cross of the Navy.
Of course, the cargo carried on the I-30 did not disappoint everyone, including engineering drawings of germany's scarce 3300 pounds of mica, 1425 pounds of shellac and the extremely important Type 91 aviation torpedo, plus a prototype of the E14YI seaplane. In return, German engineers conducted a detailed study of the I-30 submarine, and they found that although the boat surpassed the German submarine in terms of endurance, the engine noise was too loud and could be easily detected by the escort fleet. To show their generosity, the Germans specially installed a new passive sonar for the I-30, as well as a more superior 88 mm anti-aircraft gun.
On August 22, the I-30 submarine returned to Japan with a set of design drawings and samples of Germany's most developed long-range early warning radar aircraft, bomber bomb delivery system, as well as 100 million yen worth of industrial diamonds and 50 Enniger code machines. After two months of sea travel, the I-30 finally arrived safely in Singapore on October 13.
As a maiden voyage, the I-30 seemed to have done a pretty good job, but by the time he returned to Japan, Endo's good fortune seemed to run out. After being refueled, the I-30 accidentally struck and sank while returning to its home port, Kure Port( an important Japanese military port. Although most of the crew was able to escape, all the strategic supplies that had been painstakingly transported back were lost.
The I-30's failure, while frustrating, was the first attempt at the German-Japanese underwater lines of communication. Subsequently, at the suggestion of German Field Marshal Manstein, the underwater communication line between Germany and Japan began to be normalized.
U-511 submarine of the German Navy
On May 10, 1943, the U-511 submarine belonging to the German Navy, carrying the most advanced all-electric propulsion torpedo and the blueprints of the Messerschmidt Me163 rocket interceptor that Japan dreamed of, departed from Lorient, France, and arrived in Kure Harbor, Japan, on August 7, becoming the first German submarine to reach Japan. (After completing the transport mission, the U-511 submarine did not return to Germany, but as the biggest gift of the trip, the accompanying supplies were handed over to the Japanese Navy for research purposes.) ）
The commander of the First Submarine Detachment of the German Navy, Winter, received the I-8 captain Yuda Sadatoshi
Just one month after the departure of the U-511 submarine, the modified I-8 submarine also sailed out of Kure Harbor, Japan, and after passing through the island of Tsukishima, the target was still set at Lorient, France. The I-8 was loaded with a large number of cargo, including powerful samples of the Type 93 acid torpedo and a full set of engineering drawings, plus quinine, lead, rubber and other materials that the Germans urgently needed. After successfully sailing into the Atlantic, the I-8 was entangled by British air patrol aircraft, but the experienced captain took the timely change of course and changed the destination to Brest. The British plane did not know the deception, so that the Japanese boat successfully escaped. On 22 August, the I-8, escorted by German warships, finally staggered into Brest.
On October 5, the I-8, which had successfully completed its mission, was on its way home, and it was already loaded with various weapons drawings sent by Germany, including Zeiss artillery sights, Maybach 12-cylinder 700 hp tank engines, chronometers, samples of various individual weapons, and other supplies. After a month and a half of thrilling sailing, the I-8 successfully returned to Kure Harbor, and all the crew were personally received by the Minister of Naval Order, Yuji Nagano.
<h1 class = "pgc-h-arrow-right" data-track="19" > the success of the U-511 submarine and the I-8 submarine, both Germany and Japan benefited a lot, but due to the negligence of secrecy, the Allies gradually realized the importance of "willow transport", so they began to spend a lot of energy to find submarines on both sides of the mission. With the American codebreaker genius Herbert. Oliver Yardley deciphered the most complex high-level radio code of the Ministry of Foreign Affairs in the Japanese cryptography system, and the movement of Japanese submarines began to be mastered by the US military. </h1>
The I-34 submarine was hit by a torpedo
The I-34 was followed by the I-8 to Europe, but it was not as lucky as the I-8. Shortly after its departure, the U.S. military secretly reported its whereabouts to the British Navy, and the British submarine Taurus successfully ambushed the I-34 in the Atlantic.
The Japanese were not alarmed by the sinking of the I-34, but attributed it to an accident, after which the Japanese sent the I-29, which was experienced in combat, to Europe. The I-29 was full of precious metals such as gold, tin, and lead, plus the technical information of the "Akagi" aircraft carrier specially requested by the German side, and carefully sailed all the way to Lorient, although the British got the news in advance, the I-29 slipped under the eyes of the British under the command of captain Kiri Ying Ichisho.
On March 11, 1944, the I-29 arrived in Lorient and waited for a long time for the Germans to provide them with design drawings for the IXC/40 ocean-going attack submarine, new sonar decoys, a full set of information on the Me262 jet fighter, a physical WHK509A rocket engine, and a large number of top-secret documents, and a box containing uranium-235 compounds was also loaded on the submarine by four German agents.
The Atlantic Ocean was already buzzing, but the I-29 sailed safely into the Indian Ocean and into Singapore in July. After learning that the I-29 carried uranium-235 through the japanese army's telegrams, the US military could not help but take a breath of cool air. In order to ensure the sinking of the I-29, the US military not only sent 3 submarines to intercept, but also sent a large number of reconnaissance aircraft and anti-submarine aircraft to assist the attack. On the way home, the I-29 had clearly relaxed, and instead of hiding its whereabouts, it chose to surface and sail to Japan with all its might.
Just as the I-29 was traveling to the Bashi Strait between Taiwan Island and Luzon Island in the Philippines, the US Navy submarine "Sawfish", guided by a reconnaissance aircraft, launched a torpedo attack on it and successfully sank it. As for the strategic supplies carried on the boat, it sank into the Pacific Ocean with the I-29.
The sinking of the I-29 caused a huge blow to the "Willow Transport", and at the same time, the gradual deterioration of the battlefield situation also made Germany and Japan no longer have the strength to complete this "submarine" exchange.
Photo of U-234 surrendering to U.S. forces
On the eve of the fall of Nazi Germany, at Hitler's personal behest, the German Navy's U-234 submarines carried out the last transport mission of the Willow Transport.
In this mission, the U-234 boat not only carried Germany's newly developed Hs-293 gliding guided bomb, 540 kilograms of uranium oxide and a large number of Germany's top military technical data, but also carried a top German aeronautical engineer, a radar expert and 2 Japanese scientists who had been sent to Germany to study.
However, the Luck of the Japanese was so bad that germany surrendered just as the U-234 boat sailed into the Indian Ocean. Realizing that everything was over, Captain Feller decisively chose to surrender to the Allies, and the U-234, along with the supplies on board, became all the Allied trophy.