The Japanese submarine I-34 under commander Irie Tatsushi, departed Kure on the first leg of a "Yanagi" mission to Nazi-occupied France.

Code-breakers at Hut 7 in Bletchley Park deciphered radio traffic transmitted in diplomatic code concerning I-34's mission between Tokyo and Berlin.

[1] On the morning of 13 November 1943, 30 mi (48 km) off Penang the officer of the watch on Taurus sighted the large submarine I-34 running on the surface at 14 kn (26 km/h; 16 mph) despite a rain squall.

Due to the shallow water in the region, when Wingfield tried to evade the attack by diving, Taurus' bow became stuck in the soft, muddy seabed.

Thirteen members of the crew 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 submarine, which had taken on almost a ton of water.