Yanagi missions

The , or more formally the , were a series of submarine voyages undertaken by the Imperial Japanese Navy (IJN) during the Second World War, to exchange technology, skills and materials with Japan's Axis partners, principally Nazi Germany. These voyages had to run the gauntlet of the Western Allies naval superiority in the Indian and Atlantic Oceans; of the five westbound voyages, three arrived safely, with two submarines sunk ''en route'', while of the three successful vessels only one completed her return voyage, with two sunk before reaching home.

The ''Yanagi'' missions were matched by several reciprocal voyages by German U-boats, though these were outside the ''Yanagi'' scheme, as were several blockade-running cargo voyages to and from the Far East.

The ''Yanagi'' missions

The ''Yanagi'' missions were:

In April 1942 departed Kure, Japan with a cargo of mica and shellac, and plans of the Type 91 aerial torpedo; after missions in the Indian Ocean with other IJN submarines, she detached in June to proceed to Lorient, arriving there in August 1942. She departed France later that month carrying German military technology, including plans for and a complete set of a Würzburg radar, eight torpedoes and five torpedo data computers, anti-tank guns, diamonds, 20mm anti-aircraft guns, and fifty Enigma machines, and arrived at Singapore in October. However, she struck a British mine on leaving Singapore for the last stage to Japan. Some equipment was salvaged, but most was lost.

In June 1943 departed Kure with plans of the IJN's Type 95 torpedo, a reconnaissance aircraft and submarine equipment, and collected a cargo of tin, rubber and quinine at Singapore. She also carried a spare crew of 48 men from Kure tasked with bringing back a German U-boat, ''U-1224'', which the '' Kriegsmarine'' had transferred to the IJN for examination and reverse engineering. The ''I-8'' rendezvoused with the German submarine ''U-161'' from Lorient who transferred two German technicians who installed a radar detector. She arrived at Brest in August. ''I-8'' departed France in October 1943 with a variety of German technology, including: bomb and anti-aircraft gunsights, marine chronometers, a Daimler-Benz torpedo boat engine, electric torpedoes, machine guns, and penicillin, arriving at Kure in December after a round-trip voyage of .

In October 1943 departed Kure for Singapore. At Singapore, she picked up a cargo of tin, tungsten, rubber and opium. She departed Singapore on 11 November but was intercepted and sunk on 13 November in the Straits of Malacca by the British submarine HMS ''Taurus''.

In November 1943 departed Kure for Singapore to pick up a cargo of tin, tungsten, zinc, rubber and quinine. She departed Singapore in December 1943 for Nazi-occupied France, and reached the Bay of Biscay in March 1944. She was escorted by German warships and aircraft and came under heavy attack by Allied aircraft, but arrived safely at Lorient. ''I-29'' departed Lorient in April 1944 with considerable German technology, including a Walter rocket engine and plans for the jet-powered Me 262 and the rocket-powered Me 163. She arrived at Singapore in July, but was sunk with her cargo en route to Japan in the Luzon Strait by the American submarine USS ''Sawfish'' on 26 July 1944.

In March 1944 left Kure with a cargo of metals, including gold, and a team of technicians who were to study German anti-aircraft techniques, stopping at Singapore to pick up other cargo, including rubber and opium. ''I-52'' reached the South Atlantic and successfully rendezvoused with ''U-530'' from Lorient on 23 June to embark a German liaison officer, two radio operators, the current German naval code and a Naxos radar detector. However, that night she was detected by radar-equipped Grumman TBF Avenger aircraft from an American hunter-killer group centered on the escort carrier USS ''Bogue'', which dropped sonobuoys and "Fido" homing torpedoes, sinking ''I-52'' with all hands (95 crew, 14 passengers and the three German sailors) near , west of the Cape Verde Islands. It is believed that on her return voyage to Japan she would have been carrying uranium oxide.

''I-52's'' voyage was the last ''Yanagi'' mission undertaken by the IJN.

Reciprocal voyages

The German U-boat arm made several reciprocal exchange voyages, though these were outside the ''Yanagi'' scheme; they also made a number of blockade-running voyages, also separate from the ''Yanagi'' missions.

From February to June 1943 sailed to the Indian Ocean from Kiel, meeting with ''I-29'' in the Mozambique Channel. ''U-180'' transferred Subash Chandra Bose, future leader of the Indian National Army, and received two tons of gold picked up from Penang in payment for German goods so far received.

In May 1943 sailed for Japan from Lorient, arriving in Kure in August. Code-named 'Marco Polo I' she was transferred to the IJN as an exchange in submarine technology, and was commissioned by them as ''RO-500''.

In February 1944 , code-named 'Marco Polo II', was transferred to the IJN at Kiel, commissioned as ''RO-501'' and set sail under a Japanese crew, to rendezvous with ''I-8'' to refuel, and proceed to Penang with precious metals, uncut optical glass, and blueprints and models for building Type IX U-boats and Messerschmitt Me 163 ''Komet'' rocket planes. She was intercepted and sunk west of the Cape Verde islands by USS ''Francis M. Robinson'' of the hunter-killer group on 13 May.

On 5 December 1944 sailed from Bergen, Norway to deliver parts and plans for Me 262s and 1,857 flasks containing 65 tonnes of mercury under Operation Caesar. She ran aground and had to return to Bergen, which suffered a British bombing raid on 12 January 1945 that delayed repairs. ''U-864'' sailed again on 6 February 1945, but was detected and sunk by the British submarine HMS ''Venturer'' in the Norwegian Sea in the action of 9 February 1945, the only time one submarine was sunk by another while submerged.

In March 1945 sailed from Kristiansand for Japan with 1,210 tons of uranium oxide, an Me 262 jet fighter, and plans for new electric torpedoes, the last attempt to be made, but she was overtaken by the German surrender and was taken into custody by the USN off Newfoundland.Blair vol II p692-4

Notes

References

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External links

''Yanagi missions''
at history.net; retrieved 26 September 2018
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Imperial Japanese Navy