Soemu Toyoda
Koga was killed when his plane, a Kawanishi H8K ("Emily") flying boat, crashed during a typhoon between Palau and Davao while overseeing the withdrawal of the Combined Fleet from its Palau headquarters on March 31, 1944. His Chief of staff, Vice Admiral Shigeru Fukudome survived ditching in a second airplane off Cebu and was held captive by Filipino guerrillas, during which time Koga's battle plans found their way into Allied hands. His death was not announced until May 1944 when he was formally replaced by Admiral Soemu Toyoda.