The Action of 13 November 1943 was a submarine engagement of World War II. It resulted in the sinking of the Japanese Navy's Kaidai Junsen Type B1 submarine I-34 in the Strait of Malacca by the British Royal Navy submarine HMS Taurus. I-34 which was on a Yanagi Mission; an underwater convoy secretly shipping goods between Japan and their German allies.
The Japanese submarine I-34 under commander Irie Tatsushi, departed Kure on the first leg of a "Yanagi" mission to Nazi-occupied France. At the time she was the third Japanese submarine to undertake such a mission. Code-breakers at Hut 7 in Bletchley Park however intercepted and deciphered radio traffic transmitted in diplomatic code concerning I-34's mission between Tokyo and Berlin. The message was then relayed to the submarine operating in the area: HMS Taurus under the command of Lieutenant Commander Mervyn Wingfield operating from a base in Ceylon.
On the morning of the 11 November I-34 departed Seletar for Penang. Before the submarine would have entered the South Atlantic the Germans had planned to refuel I-34 in the Indian Ocean from a supply ship. When she departed I-34 was carrying a cargo of tin, tungsten, raw rubber and opium.
On the morning of 13 November 1943, 30 miles (48 km) off Penang the officer of the Watch on Taurus sighted the large submarine I-34 running on the surface at fourteen knots despite a rain squall at the time. Wingfield soon matched and fired a spread of six torpedoes and of these one managed to hit I-34's starboard side just below her conning tower and soon sank rapidly. Eighty-four crew members were killed and only fourteen survivors managed to escape the wreck and were rescued by a Malay junk.
The following day a Japanese subchaser CH-20 from Penang attacked Taurus in the morning. Wingfield had to dive deep and in the shallow sea but soon after Taurus's bow got stuck in the soft muddy seabed. However after a pattern of depth charges were dropped over Taurus the explosions shook her free. Wingfield went to periscope depth, surfaced and engaged with his deck gun severely damaging the subchaser. Thirteen were killed including the captain and another seventeen wounded but before any further action could follow a Japanese aircraft came into view and forced Wingfield into an emergency dive which endangered the sub with almost a ton of water. Taurus however escaped with only minor damage and managed to make it back to her base at Ceylon.
Following the loss of I-34 the Imperial Japanese Navy diverted all Europe-bound submarines away from Penang. I-34 was the first Japanese submarine to be sunk by a Royal Navy submarine.