How did the Japanese Pearl Harbor strike force cross the Pacific without being detected?
Short answerIt avoided shipping lanes and surveillance while American planners wrongly assumed Japan lacked the range and shallow-water attack capability for Pearl Harbor.
NotesJapan selected a northern route with little merchant traffic and no satellite surveillance or continuous long-range aerial search. The United States was not yet at war and expected the main Japanese attack to fall on the Philippines rather than Hawaii. American assumptions also held that the carrier force lacked the reach for Pearl Harbor and that aerial torpedoes could not operate effectively in its shallow water. The strike therefore exploited physical gaps in observation reinforced by confident but incorrect intelligence judgments.