Battle of Midway, 3-6 June 1942: Composition of U. S. Forces

United States Pacific Fleet and Pacific Ocean Areas

Adm. Chester W. Nimitz, USN, Commander in Chief

Carrier Striking Force

Rear Adm. Frank Jack Fletcher, USN

Task Force 17 (TF 17)

Rear Adm. Frank Jack Fletcher, USN

Chief of Staff, Capt. Spencer S. Lewis, USN

Task Group 17.5 (TG 17.5)

Carrier Group

Capt. Elliot Buckmaster, USN

USS Yorktown (CV-5) - Capt. Elliot Buckmaster, USN

Damaged by aircraft (bombs and torpedoes) from Japanese carrier Hiryu 4 June 1942, torpedoed by Japanese submarine I-168 on 6 June 1942, and capsized and sank on 7 June 1942.

Commander Yorktown Air Group (CYAG) - Lt. Comdr. Oscar Pederson, USN

Fighting Squadron 3 (VF-3) (including elements of VF-42) Lt. Comdr. John S. Thach, USN

25 Grumman F4F-4 (Wildcat)

Bombing Squadron 3 (VB-3) Lt. Comdr. Maxwell F. Leslie, USN

17 Douglas SBD-3 (Dauntless)

"Scouting Squadron 5 (VS-5)" (the temporarily redesignated Bombing Squadron 5) Lt. Wallace C. Short Jr., USN

16 Douglas SBD-3 (Dauntless)

Torpedo Squadron 3 (VT-3) Lt. Comdr. Lance E. Massey, USN (KIA)

12 Douglas TBD-1 (Devastator)

Task Group 17.2 (TG 17.2)

Cruiser Group

Rear Adm. William W. Smith, USN

USS Astoria (CA-34)

USS Portland (CA-33)

Ship Units, Cruiser Scouting Squadron 4 (VCS-4) and Cruiser Scouting Squadron 6 (VCS-6)

8 Curtiss SOC/Naval Aircraft Factory SON (Seagull)

Task Group 17.4 (TG 17.4)

Destroyer Screen

Capt. Gilbert C. Hoover, USN

Commander Destroyer Squadron 2 (ComDesRon 2)

USS Hammann (DD-412) - torpedoed and sunk by Japanese submarine I-168 on 6 June 1942.

USS Hughes (DD-410)

USS Morris (DD-417)

USS Anderson (DD-411)

USS Russell (DD-414)

USS Gwin (DD-433) (diverted to join Yorktown, arrived on 5 June 1942)

Task Force 16 (TF 16)

Rear Adm. Raymond A. Spruance, USN

Chief of Staff, Capt. Miles R. Browning, USN

Task Group 16.5 (TG 16.5)

Carrier Group

Capt. George D. Murray, USN

USS Enterprise (CV-6)

Capt. George D. Murray, USN

Commander Enterprise Air Group (CEAG) - Lt. Comdr. C. Wade McClusky, USN

Fighting Squadron 6 (VF-6) Lt. James S. Gray, Jr., USN

27 Grumman F4F-4 (Wildcat)

Bombing Squadron 6 (VB-6) Lt. Richard H. Best, USN

15 Douglas SBD-2/SBD-3 (Dauntless)

Scouting Squadron 6 (VS-6) Lt. W. Earl Gallaher, USN

17 Douglas SBD-3 (Dauntless)

Torpedo Squadron 6 (VT-6) Lt. Comdr. Eugene E. Lindsey, USN (KIA)

14 Douglas TBD-1 (Devastator)

USS Hornet (CV-8)

Capt. Marc A. Mitscher, USN

Commander Hornet Air Group (CHAG) - Lt. Comdr. Stanhope C. Ring, USN

Fighting Squadron 8 (VF-8) Lt. Comdr. Samuel G. Mitchell, USN

27 Grumman F4F-4 (Wildcat)

Bombing Squadron 8 (VB-8) Lt. Comdr. Robert R. Johnson, USN

19 Douglas SBD-3 (Dauntless)

Scouting Squadron 8 (VS-8) Lt. Comdr. Walter F. Rodee, USN

15 Douglas SBD-1, SBD-2, and SBD-3 (Dauntless)

Torpedo Squadron 8 (VT-8) Lt. Comdr. John C. Waldron, USN (KIA)

15 Douglas TBD-1 (Devastator)

Task Group 16.2 (TG 16.2)

Cruiser Group

Rear Adm. Thomas C. Kinkaid, USN

Commander Cruiser Division 6 (ComCruDiv 6)

USS New Orleans (CA-32)

USS Minneapolis (CA-36)

USS Vincennes (CA-44)

USS Northampton (CA-26)

USS Pensacola (CA-24)

Ship Units, Cruiser Scouting Squadron 5 (VCS-5) and Cruiser Scouting Squadron 6 (VCS-6)

20 Curtiss SOC/Naval Aircraft Factory SON (Seagull)

USS Atlanta (CL-51)

Task Group 16.4 (TG 16.4)

Destroyer Screen

Capt. Alexander R. Early, USN

Commander Destroyer Squadron 1 (ComDesRon 1)

USS Phelps (DD-360)

USS Worden (DD-352)

USS Monaghan (DD-354)

USS Aylwin (DD-355)

Destroyer Squadron 6 (DesRon 6)

Capt. Edward P. Sauer, USN

USS Balch (DD-363)

USS Conyngham (DD-371)

USS Benham (DD-397)

USS Ellet (DD-398)

USS Maury (DD-401)

Oiler Group

USS Cimarron (AO-22)

USS Platte (AO-24)

USS Dewey (DD-349)

USS Monssen (DD-436)

Task Force 7 (TF 7)

Submarines 

Rear Adm. Robert H. English, USN

Commander Submarine Forces, Pacific Fleet (ComSubPac)

Pearl Harbor, Territory of Hawaii

Task Group 7.1 (TG 7.1)

Midway Patrol

USS Cachalot (SS-170)

USS Flying Fish (SS-229)

USS Tambor (SS-198)

USS Trout (SS-202)

USS Grayling (SS-209)

USS Nautilus (SS-168)

USS Grouper (SS-214)

USS Dolphin (SS-169)

USS Gato (SS-212)

USS Cuttlefish (SS-171)

USS Gudgeon (SS-211)

USS Grenadier (SS-210)

Support Patrol

Task Group 7.2 (TG 7.2)

USS Narwhal (SS-167)

USS Plunger (SS-179)

USS Trigger (SS-237)

Task Group 7.3 (TG 7.3)

USS Tarpon (SS-175)

USS Pike (SS-173)

USS Finback (SS-230)

USS Growler (SS-215)

Patrol Wings, Task Force 9 (TF 9)

Rear Adm. Patrick N. L. Bellinger, USN

Shore-Based Air, Midway

Capt. Cyril T. Simard, USN  

Patrol Wing 1 Detachment (PatWing 1 Det)

Comdr. F. Massie Hughes, USN

Patrol Wing 2 Detachment (PatWing 2 Det)

Lt. Comdr. Robert C. Brixner, USN

32 Consolidated PBY-5 and PBY-5A (Catalina)

Torpedo Squadron 8 Detachment (VT-8 Det)

Lt. Langdon K. Fieberling, USN (KIA)

6 Grumman TBF-1 (Avenger)

Marine Aircraft Group 22 (MAG 22)

Second Marine Aircraft Wing

Lt. Col. Ira L. Kimes, USMC

Marine Fighting Squadron 221 (VMF-221) 

Maj. Floyd B. Parks, USMC (4 June 1942) (KIA)

Capt. Kirk Armistead, USMC (4-6 June 1942)

20 Brewster F2A-3 (Buffalo)

7 Grumman F4F-3 (Wildcat)

Marine Scout Bombing Squadron 241 (VMSB-241) 

Maj. Lofton R. Henderson, USMC (4 June 1942) (KIA)

Maj. Benjamin W. Norris, USMC (4-5 June 1942) (KIA)

Capt. Marshall A. Tyler, USMC (5-6 June 1942)

11 Vought SB2U-3 (Vindicator)

16 Douglas SBD-2 (Dauntless)

Seventh Army Air Force Detachment

Maj. Gen. Willis P. Hale, USAAF

Capt. William F. Collins, Jr., USAAF

2 Martin B-26 (Marauder)

2 Martin B-26B (Marauder)

Lt. Col. Walter C. Sweeney Jr., USAAF

13 Boeing B-17 (Flying Fortress)

Maj. George A. Blakey, USAAF

6 Boeing B-17 (Flying Fortress)

Midway Local Defenses

Capt. Cyril T. Simard, USN

Sixth Marine Defense Battalion (reinforced), Fleet Marine Force 

Col. Harold D. Shannon, USMC

Reinforcing Units

2d Raider Battalion, Company "C" (Sand Island) 

2d Raider Battalion, Company "D" (Eastern Island) 

Antiaircraft and Special Weapons personnel, Third Defense Battalion

22d and 23^rd Provisional Infantry Companies

Motor Torpedo Boat Squadron 1 (MTBRon 1) 

Lt. Clinton McKellar Jr., USN

Midway Island

USS PT-20 

USS PT-21 

USS PT-22 

USS PT-24 

USS PT-25 

USS PT-26 

USS PT-27 

USS PT-28 

Kure Island 

USS PT-29 

USS PT-30 

District Craft

Tamaha (YNT-12)

Island Patrols

French Frigate Shoals 

USS Thornton (AVD-11)

USS Ballard (AVD-10)

USS Clark (DD-361)

USS Kaloli (AOG-13)

Pearl and Hermes Reef 

USS Crystal (PY-25)

USS Vireo (ATO-144)

Lisianski

YP-284

Gardner Pinnacles

YP-345

Laysan

YP-290

Necker

YP-350

Midway Refueling Unit

Comdr. Harry R. Thurber, USN

USS Guadalupe (AO-32)

USS Blue (DD-387)

USS Ralph Talbot (DD-390)

Midway’s Operational Lesson: The Need for More Carriers

by Robert J. Cressman

The Japanese employing six aircraft carriers at one time, as they did in the attack on Oahu on 7 December 1941, proved a radical undertaking. The U.S. Navy’s carriers, by contrast, had never numbered more than two or three during infrequent maneuvers, and the war’s coming in 1941 found only three in the Pacific, Lexington (CV-2), Saratoga (CV-3), and Enterprise (CV-6).

Carriers had been a part of the U.S. Fleet since Langley (CV-1), nicknamed “The Covered Wagon” pioneered such operations in 1922, and forward-thinking naval officers employed them in the annual maneuvers, or Fleet Problems, with varying degrees of success. The war that descended with such suddenness on the Pacific Fleet on 7 December 1941, however, found that arm of the fleet relatively outnumbered by the Japanese. The six carriers whose planes had attacked Oahu outnumbered the U.S. Navy’s flattops two to one. The Japanese carriers were concentrated – the American were scattered: one on the way to Midway (Lexington); another at San Diego, preparing to return to Hawaiian waters (Saratoga); and the third returning from Wake Island (Enterprise).

The three U.S. carriers involved at Midway differed in experience and in how they operated. Yorktown (CV-5), the first Atlantic Fleet carrier to deploy to the Pacific, had been operating under wartime conditions in the Atlantic during much of 1941; her squadrons at Midway, however, came from two different air groups: her own (VB-5), and those from Saratoga. The latter warship had been put out of action by a submarine torpedo in January 1942 and had landed her squadrons on Oahu (VB-3, VT-3, and VF-3). Only VB-5 had served in Yorktown for any length of time, from the operations in the Atlantic in 1941 through the Marshalls-Gilberts Raids, Lae-Salamaua, and the Coral Sea.

Enterprise had been involved from 7 December 1941, when elements of her air group encountered Japanese planes over Oahu; she had then participated in the Marshalls-Gilberts Raids, and had attacked Wake and Marcus, and had rode shotgun for Hornet (CV-8), the second Atlantic Fleet CV transferred to the Pacific, when that carrier took Lt. Col. James H. Doolittle’s B-25s to bomb targets in Japan. Of her squadrons, VB-6, VF-6, and VT-6 had served since the beginning; VS-6 had taken heavy losses early in the war, and had been spelled during the Halsey-Doolittle mission by VB-3.

Hornet, only commissioned in October 1941, had come to the Pacific and immediately taken part in the Halsey-Doolittle Raid; she was easily the least experienced carrier of the three.

It must be remembered that carrier operations in the U.S. Navy were in a state of flux – the air groups learning as they went along, and in the crucible of combat. On 4 June 1942, Enterprise and Hornet, in Task Force 16 (Rear Admiral Raymond A. Spruance), launched their respective attack groups employing a “deferred departure” plan, which sent off the fighters first, then the scout-bombers, then the torpedo planes. All loitered about the ship until the entire group was airborne before setting out for the enemy en masse. As the Japanese steamed at the extreme range of their fighter and torpedo planes’ fuel capacities this left no margin for error. Hornet’s fighters launched first and wasted much of their fuel over the ship while the rest of the strike slowly got airborne, one aircraft at a time. None of the fighters ever returned to the ship, or sighted the enemy. Enterprise’s fighters attached themselves to the Hornet’s torpedo planes (the ill-fated VT-8), while Enterprise’s torpedo planes went unescorted. Hornet’s dive bombers did not find the enemy, VS-8 returning to the ship directly and VB-8 returning to the ship via Midway.

Yorktown, however, operated differently. Her attack group, less VB-5 which Rear Admiral Frank Jack Fletcher, Commander, Task Force 17, retained on board as a reserve strike and search group, launched according to a “running rendezvous,” the dive bombers taking off first, followed by the torpedo planes, with the higher speed fighter escort launching last. VT-3, VB-3, and VF-3 proceeded directly toward the target immediately after launch, with the torpedo squadron at low altitude, the dive bombers high, and the fighters closing in from behind. The group then merged together well along its base course, with all elements arriving over the enemy fleet simultaneously – Yorktown’s air group was the only one of the three to attack as a group. Their providential arrival simultaneously with that of Enterprise’s VB-6 and VS-6 spelled the doom of Akagi, Kaga, and Soryu.

The separation of Task Forces 16 and 17, meanwhile, proved detrimental when the only Japanese carrier that survived the initial destructive attacks, Hiryu, managed to cobble together the strike that stopped Yorktown and forced Rear Admiral Fletcher to transfer his flag and turn over tactical command to Rear Admiral Spruance. The Japanese carriers tended to separate during battle, each with their own screen, spreading out and lessening the impact of antiaircraft fire and dispersing the combat air patrol (CAP). The American carriers at Midway did likewise to a degree, so that TF-17 had fewer fighters and fewer antiaircraft guns afloat to defend Yorktown than would have been the case if Enterprise and Hornet were operating in company. Yet the need to concentrate the carriers, to put up a formidable combat air patrol and take advantage of the gunfire of the screening cruisers and destroyers with their 5-inch batteries (as well as the 1.1-inch, later 40-millimeter, and 20 millimeter guns in profusion) could not be fully realized until carriers were built in sufficient numbers to group several in one formation. Until the war construction programs of Essex (CV-9) class carriers and Independence(CVL-22) class small carriers would make themselves felt, one or two carriers and their respective screens would have to suffice.

Nevertheless, the employment of aircraft carriers at Midway proved crucial, for without them, ships of either side could find themselves at the mercy of an opponent’s planes. The destruction of the Japanese carriers on 4 June left one group of Japanese warships, detached to bombard Midway, totally unprotected, and when a collision damaged two heavy cruisers and impaired their speed, they could only proceed slowly, with two destroyers for a screen. Consequently, dive bombers from Hornet and Enterprise pounded Mogami and Mikuma, sinking the latter and inflicting further damage on the former.

America’s overwhelming capacity for production, something Admiral Yamamoto Isoroku feared at the outset of hostilities, eventually produced carriers in such numbers that task groups of four carriers (three CV-9 class and a CVL-22 class) would be the norm rather than the exception. Admiral Chester W. Nimitz, Commander in Chief, U.S. Pacific Fleet, had promised to “do the best we can with what we have.” Nimitz and his subordinates achieved victory with the weapon that had been forged since the 1920’s, the aircraft carrier and her embarked air group, that possessed the ability to project power over long distances, the power that aircraft carriers possess today of unprecedented utility.

Navy Cryptology and the Battle of Midway: Our Finest Hour

by Lieutenant Commander Philip H. Jacobsen, USN (Ret.)

(Editor's note: the following is the text of an address given by LCDR Jacobsen to a gathering of Naval Security Group personnel at San Diego in 2000. It has been edited slightly for clarity and to better suit this format.)

The Advent of U.S. Naval Cryptology

Although my part in the Battle of Midway was very small, I appreciate this opportunity to relate to you some of the more important achievements of my contemporary naval cryptologists that made the success of the Battle of Midway possible. As a current member of the Naval Security Group, you can take pride in the great accomplishments of your predecessors, not only related to the Battle of Midway but long before World War II as well as throughout World War II. There are not many naval cryptologic veterans alive today that were involved in providing the communications intelligence information that gave our inferior forces on land, sea and especially in the air the equalizer of knowing the composition of enemy forces, and when and where those huge Japanese forces would attack U.S. territory under Admiral Yamamoto's grandiose invasion plan.

This crucial communications intelligence information, when combined with the heroic actions of fighting forces under the brilliant command of Admiral Nimitz, led to the great U.S. victory in the Battle of Midway. We should keep in mind that intelligence itself does not win battles. However, I believe the lesson of the Battle of Midway is that good, solid intelligence can make the difference between winning and losing a crucial battle for our country. I hope you will keep this in mind in the future. What was the genesis of the naval cryptologic success at the Battle of Midway. So much was involved in building up dedicated experts in all the various fields of cryptology that it is impossible to point to one single source. Credit must be given to many individuals who operated under difficult conditions, extremely limited budgets, and poor promotional opportunities. This relatively tiny group of dedicated individuals accomplished much in their efforts over the years to keep abreast of the growing force of the Japanese navy and their ever increasing communications security precautions. With the Japanese instigation of war with the U.S., this cadre of technical experts made it relatively easy to expand into a large organization and to immediately provide increasingly vital intelligence to not only U.S. Navy operational forces but also to U.S. Army and Allied forces in the Southwest Pacific and Indian Ocean areas.

Attacking JN-25

Despite successes with prior Japanese naval and diplomatic codes, the high priority placed on the small group of naval cryptologists to provide decrypts of Japanese diplomatic communications precluded any significant decrypts of the current Japanese fleet code, JN-25B. Immediately after the Japanese attack on Pearl Harbor, Station HYPO in Hawaii under Commander Joseph J. Rochefort was given the authority to attack JN-25B. By early 1942, HYPO was producing some usable JN-25B decrypts. Station CAST at Corregidor, which was moved to Melbourne after the Philippines fell, and Station NEGAT in Washington soon followed with a number of important JN-25B decrypts. HYPO first reported an offensive action in the 'AK' or Hawaiian area which culminated in the ineffectual bombing of Oahu on the night of 4/5 March 1942. Rochefort determined that the long range Japanese seaplane was refueled by a submarine at the isolated island of French Frigate Shoals. This information would later play a vital part of the preparation for the Battle of Midway.

The Japanese Plan for Midway

The Japanese geographical designator 'AF' began to appear in partially decrypted messages as early as 4 March 1942. On March 13, Corregidor firmly identified 'AF' as Midway. Melbourne and Washington confirmed that 'AF' was Midway from subsequent decrypts, but for some unexplained reason Washington evaluated it as a communications designator, not a geographical designator even though Midway was obviously not a Japanese communications station. Decrypts in late April by Melbourne and Hawaii showed intentions of hostile Japanese action at Dutch Harbor and Kodiak in the Alaskan area. Beginning on May 1, activity in Japan proper reflected preparations for both the Midway and Alaskan areas and provided detail of Japanese planning and the size of the forces committed to each objective. As the Japanese ships departed their anchorages, communications intelligence provided information on their future disposition. Both Melbourne and Hawaii reported the pairing of Japanese Carrier Divisions 1 and 2 for exercise activity in home waters on May 3rd and 12th. In addition, HYPO provided a decrypted message of May 7, 1942 containing the complete agenda for an "aviation conference" on May 16 called by Vice Admiral Nagumo in Kagoshima, Kyushu. Also to be discussed was an "amphibious assault" and battle for "air superiority" together with a study of organizations for use in dive bombing, torpedo attacks, bombing, and strafing to wipe out local resistance. For some time the status of Admiral Kondo's powerful Second Fleet was clouded. Finally on May 8,1942, HYPO correctly associated the carriers of the 1st Fleet with several important 2nd Fleet elements and warned of a possible creation of a strike force organization under Vice Admiral Nagumo, Commander 1st Air Fleet, consisting of CarDivs 1 and 2, CruDiv 8, two battleships from BatDiv 3, and other 2nd Fleet elements. These early correct conclusions gave a major advantage to the planners in the U.S. Pacific Fleet. They were reinforced by Melbourne on May 9 by a decrypt ordering destroyer screens for many of the capital ships in the Striking Force and revealing a sailing date from Sasebo of May 21.

Troubles in Washington

On May 14, Admiral King directed Admiral Nimitz to declare a state of "Fleet Opposed Invasion" and gave Nimitz complete control of all military forces, including B-17s in the Hawaiian Islands. By May 16,  Admirals King and Nimitz were in almost total agreement concerning Japanese intentions toward Midway and the Aleutians. However, this view was in sharp contrast to the confusion that reigned between OP-20-G (Station NEGAT) and War Plans staff under Admiral Richmond K. Turner. Turner placed some ridiculous restrictions on what Station NEGAT could report. On May 16, Nimitz ordered Admiral Halsey [Task Force 16 with USS Enterprise and Hornet] to return to Hawaii, indicating the Japanese would probably make simultaneous offensives against Port Moresby, Dutch Harbor, and Midway where the main striking force would be employed. Two days later, all three navy cryptologic centers reported that the Strike Force's attack would be from the northwest from N minus 2 days until N day, while Hawaii and Melbourne added that the attack would be launched from fifty miles northwest of AF. While this did not solve the attack timing problem completely, Nimitz immediately sent messages to Halsey and Fletcher [Task Force 17 with USS Yorktown] to expedite their return to Pearl Harbor as well as ordering submarine search activity off Midway to an area fifty miles northwest of the island. An acrimonious relationship between Admiral Turner and his War Plans Division and OP-20-G continued, with Turner directing Commander Redman not to comment on certain intelligence evaluations and assume that Turner's views were correct. The record suggests that the analysts in War Plans and OP-20-G were so engrossed in their own activities that they sometimes overlooked information concerning the Imperial Fleet readily available from translations in OP-20-GZ and the daily reports of the Pacific centers. While the Pacific centers were convinced that the identity of AF was Midway because of its position in the "A" or American digraphs in the Japanese designator system, various persons at OP-20-G and in Washington thought it might be Johnston Island, Samoa, the U.S. West Coast or even Hawaii itself - HYPO was aware of this lack of agreement on AF in Washington. In order to rid themselves of this annoying backbiting, Rochefort approved a ruse that was probably thought up by Jasper Holmes, the author of Double Edged Secrets. Nimitz approved the message to be sent in the clear from Midway complaining of a water shortage. Rochefort let Melbourne make the first report of the decrypt from Tokyo Naval Intelligence advising of a "water shortage at AF." Even the naysayers in Washington could not argue with this confirming evidence.

Stealing the Enemy's Secrets

Additional information about a Japanese northern force prompted Nimitz to activate Task Force 8 under Admiral Robert A. Theobald. In spite of accompanying and subsequent accurate information about Japanese intentions in the Aleutians from decrypts, Theobald chose to treat such information as enemy deception and moved his forces out of the area to the Kodiak vicinity. That allowed the enemy to pound Dutch Harbor and occupy Kiska and Attu. From information of Japanese successes in determining carrier movements simply by monitoring air to ground communications, Nimitz ordered Halsey and Fletcher to maintain radio silence, particularly among the aircraft when coming in to land. He also warned MacArthur that the Japanese were intercepting air-to-ground contacts between Port Moresby and allied planes. Nimitz also implemented a MacArthur suggestion that two or three U.S. vessels in the South Pacific conduct radio deception to create the impression that our carriers were remained in that area. On May 22, a Melbourne decrypt revealed the word "Midway" in a request for photographs of the island that had been "handed over to you." Washington published a message from Nagumo to the 11th Air Fleet showing that his carriers had 33 aircraft on board that were destined to be the nucleus of land based aircraft in the new Japanese perimeter. Their loss was completely unnoted in accounts of Japanese carrier losses. The 25th of May began with HYPO's critical discovery of the Japanese date cipher. Now the U.S. possessed the means to determine the final ingredient of the Japanese plans - when the attack would take place. Application of this information allowed Rochefort to predict that the Japanese attack on the Aleutians would occur on June 3 and on Midway on June 4. Despite objections from his staff, Nimitz decided to base his final timetable on these dates. Melbourne applied this date cipher information to older traffic and alerted the Pacific Fleet that on the 22nd of May CruDiv 8 and the battleships Kongo and Kirishima were scheduled to depart the Inland Sea of Japan. Task Force 16 (Hornet and Enterprise) under Admiral Halsey returned to Pearl on the 26th and began a whirlwind of preparation for battle. The CINCPAC Bulletin of the 26th reported that the Northern Force had begun to depart Ominato and that all the Japanese carriers were probably at sea. Admiral Nimitz advised King how much he was dependent on communications intelligence and noted that they were only copying 60 percent of Japanese naval messages and only decrypting 40 percent of those copied. King attributed all of the Navy's progress in the Pacific to the success it was having from timely information from Japanese naval codes. Without this information King said, "disaster is probable."

Preparations for Battle

On the 27th of May, the Yorktown finally limped into port, showing the damage inflicted during the Coral Sea battle. This good news was offset by some bad news from Commander Rochefort's center: a new underlying code (JN-25C) and additive cipher had been introduced that rendered unreadable almost all the texts of JN-25 messages from the 27th on. However, some previously originated messages were still readable including one from the 5th Fleet that contained tactical call signs for the Northern Force, its Strike Force, and the Occupation force for 'AQ' and 'AO' identified as Kiska and probably Attu. Again, Theobald refused to believe this intelligence and kept his force near Kodiak. Another prior message concerned the "Ichiki Detachment" to command the 2nd Combined Landing Force, which was to occupy Midway's Eastern Island. A third message revealed the intended use of civilian engineers captured on Wake Island to be used in the rebuilding of Midway. Additional warnings that the carriers were at sea were also published. On May 30, U.S. task force commanders were alerted by HYPO that direction finding had located three submarines in northern waters and one west of Midway. That day, the Yorktown (Task Force 17) slipped out of Pearl but was detected by the ComInt unit aboard the Yamato, Admiral Yamamoto's flagship. However, due to radio silence restrictions, this information was not passed on to the Japanese carriers. NEGAT in Washington reported that the carrier Ryujo was at sea with the Northern Forces and that the Commander of the 6th Army Air Force was probably aboard the Akagi. An old message produced the important information that fighter pilots from the carrier Zuikaku had been transferred to the Northern Force, ruling out the possibility that the Zuikaku could be called on to support either the Aleutian or Midway campaigns. Another message determined that major participants were called to a conference aboard the Akagi on the 26th, which meant they were still in port on that date. Melbourne's analysis of air activity in the Marshalls on June 2 led them to conclude that the Occupation Force was approaching the Marshalls. However, Admiral King's headquarters report of that day contained serious errors. It estimated that BatDivs 2 and 1, CarDiv 4, and DesRon 3, parts of the Main Body, were still in the Bonins home waters area when in fact this force was approaching the western edge of the occluded front northwest of Midway. Perhaps, more importantly, the Office of Naval Intelligence chose this moment to report the presence of a fifth carrier, and identified the carrier as the Zuikaku. Fortunately, Admiral Nimitz and his intelligence staff had confidence in the information being generated by the centers in the Pacific, and this ONI estimate was not acted on or repeated to the task forces off Midway.

Predictions Confirmed

As predicted by HYPO, the Japanese offensive against the Aleutians began on June 3 with the carriers attacking Dutch Harbor. Shortly thereafter, Midway notified Nimitz that the Japanese "Main Body" was sighted at 2100Z by a patrol plane bearing 261 degrees and a distance of 700 miles from Midway. After a second sighting of a smaller group of warships and cargo vessels, Nimitz advised that the forces sighted were the attack and occupation forces, not the main body. HYPO's report of June 3 identified Admiral Yamamoto, CINC of the Combined Fleet as in overall command and correctly identified major commanders and functions of 2nd Fleet, 1st Air Fleet, and 5th Fleet.

Just after midnight on the morning of June 4, Nimitz realized he had not yet advised the task forces how far the "Main Body" was from Midway. In addition to repeating earlier reports on its course and speed, he concluded it was now 574 miles from Midway. At 0604 Midway time, a reconnaissance plane from Midway spotted two Japanese carriers and their escorts and reported "many planes heading Midway" from 320 degrees, distance 150 miles. Less than a half hour later, Midway was attacked by Japanese carrier aircraft. Nimitz was only able to muster 47 warships and 26 submarines against the Japanese fleet of 113 warships and 16 submarines. However, the U.S. was able to concentrate its forces at Midway with a slight advantage at the scene of the battle with three carriers, 22 escorts, 234 aircraft afloat and 110 at Midway versus four carriers, 17 escorts, 229 aircraft and 17 seaplanes for the Japanese. In addition, Admiral Nimitz and his task force commanders had advance knowledge of the identity of the Japanese objectives; virtually the entire Japanese Midway and Aleutian order of battle; the organization of the Midway forces into a Striking Force, Occupation Force, Invasion Force; the preliminary and final timetables of the Midway and Aleutian Striking Forces; the general direction from which each force would approach Midway, and the Midway Strike Force's plan of attack. All of that information was supplied by communications intelligence in time to influence decisively the provisions of Admiral Nimitz's Operation Plan 29-42. In addition, luck was on the side of American forces in several key instances. Partly due to poor Midway bomber group sighting reports, two of the U.S. carrier aircraft groups [from Enterprise and Yorktown] were fortunate to locate the enemy carriers after changing their original course, while Hornet's planes failed to make any contact. The late takeoff of the #4 search plane from the cruiser Tone prevented the Japanese from discovering the presence of U.S. carriers in time to make significant operational changes.

A Victory of Intelligence

The Americans lost only one carrier, one destroyer and 147 planes, while the enemy suffered the loss of four large carriers, all their aircraft, as well as one heavy cruiser and the damage to one heavy cruiser. These losses plus the rejection of the enemy invasion and occupation forces resulted in a huge victory for the U.S. Navy early in WWII. This great success after so much bad news from Pearl Harbor, the Philippines, and Southeast Asia was a great morale booster to the American people. After the battles of Coral Sea, Midway and the Aleutians, the invaluable contributions made by communications intelligence were recognized by senior naval officials in Washington and Honolulu. In their words, communications intelligence had given the United States a "priceless advantage" over the Japanese. In few battles before or since would any navy possess an enemy's order of battle, their plan of attack, and their timetable, all of which had been provided to the U.S. Navy's high command by the communications intelligence units in Hawaii and Australia under the direction of Commander Joseph J. Rochefort and Lieutenant Rudolph Fabian, respectively.