US Navy breaks Japanese Code
25th May 1942: USN Crypto-analysts make crucial breakthrough that reveals Japanese plans to invade Midway and ambush US Fleet
In May 1942 the Japanese were supremely confident of their military capability in the Pacific. They had swept all before them and threatened Australia, Hawaii and perhaps even the west coast of America. Now they sought to bring the US Navy to battle and complete the task they had set out for at Pearl Harbor. A large force was now despatched to take the US base at Midway - and then attack the unsuspecting US Pacific Fleet when it sought to respond, in an action that would thoroughly weaken US forces for at least a year.
A very small group of US Navy officers would frustrate their plans. Led by Captain Joseph J. Rochefort at Station Hypo, the Combat Intelligence Unit, Pacific Ocean Areas, located at Pearl Harbor they had succeeded in penetrating the Japanese naval code and had read their whole operation order.