Complex sentence: Probably the best-known incident involving a G4M during the war was the attack resulting in the death of Isoroku Yamamoto of T1-323 carrying IJN Admiral Isoroku Yamamoto by American P-38 Lightnings on April 18,1943.
Split into simpler sentences: Probably the best-known incident involving a G4M during the war was the attack resulting in the death of Isoroku Yamamoto. The G4M with tail number T1-323, which was carrying the IJN Admiral Isoroku Yamamoto, was attacked and shot down by American P-38 Lightnings on April 18,1943.