The Kawanishi H8K was a flying boat used by the Imperial Japanese Navy Air Service during World War II for maritime patrol duties. The Allied reporting name for the type was "Emily". The Kawanishi H8K was a large, four-engine aircraft designed for long range and extended endurance on patrols or bombing missions typically flown alone over the ocean. The prototype first flew in January 1941, and H8K1s made their first combat sortie in March 1942. The robust H8K2 "Emily" flying boat was also fitted with powerful defensive armament, which Allied pilots had substantial respect for wherever this aircraft was encountered in the Pacific theater. Aircraft historian René Francillon called the H8K "the most outstanding water-based combat aircraft of the Second World War."