The Unauthorized History of the Pacific War

If Seth and I were to define the two main thrusts of our podcast “The Unauthorized History of the Pacific War,” it would be (1) to correct some of the mythology that has emerged over decades, and (2) to see what lessons might be gleaned that could be important were war to break out in the Pacific again.

In my view, our subject for today falls into the second category, because it’s about the impact of strategic alignment and chains of command on operational success.

Station Hypo was one of three main stations the Navy used to listen to and break Japanese naval codes. Hypo was the phonetic word for the letter “H,” which stood for Hawaii since Station Hypo was the code breaking office located in the basement of the Hawaii Naval District commander’s building in Pearl Harbor. As an aside, I visited those rooms when I was commodore in Pearl, and they were being used to store furniture for the Pearl Harbor shipyard headquarters building, but we will leave that for another potential future discussion on what’s happened to all these historic sites over the decades.

But germane to this conversation, in the early months of the war the Naval District Hawaii commander reported, not to Admiral Nimitz, but to Admiral King directly. That would be corrected in the coming months, but since Station Hypo supported combat operations in the Pacific, Admiral Nimitz certainly thought of it as one of his assets, while Admiral King’s staff in Washington saw it as solely and completely theirs, to include Station Hypo’s brilliant leader, Commander Joe Rochefort.

This led to a chain of command problem that would ultimately lead to Rochefort’s dismissal as head of Station Hypo, even after his incredible success leading to our victory at Midway.

To help us unpack all of this, to include how Station Hypo fed both King’s and Nimitz’s strategic picture, we are proud to host the chief historian of the Navy and Director of Naval History and Heritage Command, retired Rear Admiral Sam Cox.

Admiral Cox, welcome.

Station HYPO:

• What was HYPO?
• Initially known as Fleet Radio Unit Pacific, or FRUPAC
• Hawaii location for the Navy’s cryptanalysts who monitored radio intel of the Japanese.
• HYPO was one of two major stations for Allied radio intel, the other being in Melbourne, Australia.
• Under the command of DC, not Nimitz, or Kimmel for that matter.
• Conspiracy theory that HYPO never had a PURPLE machine, and therefore was unable to read Japanese traffic pre-Pearl Harbor.
• NOT TRUE. Purple was the diplomatic code, not the Naval code so HYPO had no reason to have the PURPLE machine in the first place. It would not have helped them in any way.
• HYPO’s mission after Pearl Harbor, was to decipher the Japanese JN-25 code.
• Prior to Pearl, HYPO was to decipher flag officer’s code and weather codes
• Washington worked on JN25 initially
• How much of the code was readable?
• Prior to Pearl, they had successfully broken a part of the code, only 10% before the attack.
• Who was HYPO’s CO and what kind of a man was he?
• Joseph Rochefort was a Naval enlistee, who never graduated high school. He enlisted in 1918, lied about his age and was later commissioned an Ensign in 1919. Spent several years at sea as well as a year in Tokyo as a language officer.
• He began work in Cryptanalysis in 1926
• Rochefort was assigned as head of HYPO in March 1941 by Intel officer Laurance Safford.
• Brilliant man who had a knack for solving crossword puzzles and figuring out different types of word puzzles.
• WAS NOT an eccentric as has been shown in movies.
• YES, he wore a smoking jacket while at work, only because it had pockets for his pipe and tobacco
• YES, he wore slippers at work because the concrete floors of the “dungeon” hurt his feet while he paced around trying to figure out messages.
• HYPO was different than most Naval assignments of the era...how so?
• Many of the staff of codebreakers were handpicked men by Rochefort
• Not much in the way of military discipline
• There was no real system of work, the men were allowed to play their hunches in order to decrypt the information and if that included throwing false messages around to confirm something so be it.
• There was quite a bit of guesswork involved.
• Men worked round the clock. Rochefort himself rarely went home, often slept on a cot in his office. Most men worked 12 hour shifts, 7 days a week.
• How was the JN25 code eventually “broken” what was the process?
• There were over 50,000 five-digit numeral groups to decipher
• Codebreakers didn’t necessarily break the code as they actually started to see patterns in the messages and began to plug and play if you will, the dif...

• Nimitz Pre War
• Who was he and where did he come from?
• Texas Hill Country, Fredericksburg
• Too poor to go to college, worked his tail off to go to Naval Academy
• Spent time in Japan before the war
• Nimitz was a submarine officer in his early years
• Commanded a DD in the Philippines
• Commanded a cruiser division and battleship division
• XO of SC, CO Chicago
• Highly experienced in the realm of command
• Nimitz Upon Assignment as CINCPAC
• 56 Years Old currently occupying the office of the Bureau of Navigation
• Whose decision was it to promote Nimitz to the position?
• FDR
• He had been offered the job before December 41 and turned it down for fear of upsetting senior officers.
• He was junior to some 50 other Admirals
• He feared that taking the job and leapfrogging them would have created resentment and made it more difficult to do the job.
• Nimitz the Leader
• What kind leadership style did Nimitz utilize?
• He was a people person
• Never cussed, raised his voice or dressed men down in public
• He gave his subordinates a lot of autonomy and assumed they knew their jobs until they proved they did not
• If that occurred, he spoke in low tones, was blunt but not rude or insulting
• Always looked after his men and took care of them
• Nimitz the Executive
• Juggled personalities of subordinates and his boss extremely well
• Dealings with King
• Dealings with subordinates
• Turner
• GEN Smith
• Halsey
• Towers
• JO Richardson
• MacArthur
• Spruance and Nimitz relationship
• Nimitz handled the various personalities in the Pacific in check much as Ike did in the ETO.
• Was very similar to Ike in terms of Supreme Commander, even though, Nimitz was no Supreme Commander
• What did Nimitz inherit in December 41 and how did he go about fixing the problems?
• Inherited a shattered command
• Devastated morale
• Staff, fleet and populace
• Fear of a Japanese invasion
• When he landed in Pearl on Xmas Day he asked about the relief of Wake
• When told it fell and was abandoned, he fell silent
• Didn’t take command immediately. Worked with Admiral Pye to get the lay of the land, latest issues and intel.
• Took command on December 31, 1941 aboard USS Grayling (SS-209) fittingly
• Nimitz’s Strategy 1941-42
• Be cautious, yet forceful and hit them where they least expect it
• Strike back was essential
• (Set the stage for next episode about the Hit and Run Raids)
• Nimitz’s biggest gamble
• Midway
• Recognized the role of intel and believed in it, believed in his people and their skills
• Nimitz’s Legacy
• Developed and implemented the island hopping strategy that won the war.
• Inherited a shattered fleet, trusted his subordinates, built his leadership teams and won when it was absolutely necessary.