  operation hailstone (known in japan as  torakku-tÅ kÅ«shÅ«, lit. "the airstrike on truk island") was a massive naval air and surface attack launched on february 16â17, 1944, during world war ii by the united states navy against the japanese naval and air base at truk in the caroline islands, a pre-war japanese territory. ==background==  truk was a major japanese logistical base as well as the operating "home" base for the imperial japanese navy's combined fleet. some have described it as the japanese equivalent of the us navy's pearl harbor. the atoll was the only major japanese airbase within range of the marshall islands and was a significant source of support for japanese garrisons located on islands and atolls throughout the central and south pacific. the base was the key logistical and operational hub supporting japan's perimeter defenses in the central and south pacific. to ensure air and naval superiority for the upcoming invasion of eniwetok admiral raymond spruance ordered an attack on truk. vice admiral marc a. mitscher's task force 58 had five fleet carriers ({{uss|enterprise|cv-
History_of_the_Federated_States_of_Micronesia Pacific_Ocean_theatre_of_World_War_II