Operation K (K作戦 Kē-Sakusen) was a Japanese naval operation in World War II, intended as a reconnaissance of Pearl Harbor and disruption of repair and salvage operations following the surprise attack on 7 December 1941. It culminated on 4 March 1942, with an unsuccessful attack carried out by two Kawanishi H8K "Emily" flying boats. This was the longest distance ever undertaken by a two-plane bombing mission, and one of the longest bombing sorties ever planned without fighter escort.