Battle of the Philippine Sea

The Battle of the Philippine Sea (June 19–20, 1944) was a decisive naval battle of World War II which effectively eliminated the Imperial Japanese Navy's ability to conduct large-scale carrier actions. It took place during the United States' amphibious invasion of the Mariana Islands during the Pacific War. The battle was the last of five major "carrier-versus-carrier" engagements between American and Japanese naval forces, and involved elements of the United States Navy's Fifth Fleet as well as ships and land-based aircraft from the Imperial Japanese Navy's Mobile Fleet and nearby island garrisons.

The battle was nicknamed the Great Marianas Turkey Shoot by American aviators for the severely disproportional loss ratio inflicted upon Japanese aircraft by American pilots and anti-aircraft gunners. During a debriefing after the first two air battles a pilot from the USS Lexington remarked "Why, hell, it was just like an old-time turkey shoot down home!" The lopsided outcome is generally attributed to American advantages in pilot and crew training and tactics, war technology, and ship and aircraft design, which the Japanese could not match over the course of the war. Though at the time the battle appeared to be a missed opportunity to destroy the Japanese fleet, the reality was that the Imperial Japanese Navy had lost the bulk of their carrier air strength and would never recover.

Background
With the death of Admiral Isoroku Yamamoto on 19 April 1943, Admiral Mineichi Koga had succeeded as Commander in Chief of the Combined Fleet. Under his direction, the Imperial Japanese Navy sought to engage the American fleet in a single decisive battle in early 1944.

From the start of the conflict, the Japanese war plan had been to discourage America by inflicting such severe and painful losses on her military that the public would become war weary and the American government would be convinced to allow Japan to keep her conquests in east and southeast Asia. Though at a numerical disadvantage from the outset, and an industrial disadvantage that would add to that disparity over the course of time, the Japanese high command believed they could fight the U.S. Navy in a single, decisive engagement, the Kantai Kessen, which would allow them to defeat the Americans. However, their ability to fight and win such a battle was slipping away. Imperial Navy aircrew losses suffered over the course of the earlier carrier battles at Coral Sea, Midway, and in the long Solomons campaign of 1942-43 had decimated the Japanese Navy's ability to project force with their carriers. As the Guadalcanal campaign was largely fought by the Imperial Navy, losses suffered there drastically reduced the number of skilled carrier pilots available to fill the carrier air groups. Losses suffered in the Solomons could be absorbed, replaced and made good by the US Navy, but not by the Japanese. It took nearly a year for the Japanese to reconstitute their airgroups following the Solomons campaign. Their initial plan was to engage the U.S. Pacific Fleet in early 1944, whenever it launched its next offensive, but the decisive battle necessarily had to be delayed. Meanwhile, American material production capacity, aircrew training and technological advances made a Japanese victory increasingly difficult to achieve. By the end of 1942, the Allied navies had overcome most of the technological edges Japan's ships and planes had held at the start of the war. Furthermore, by mid-1943 mass production of ships and improved aircraft began to tip the balance of forces in the favor of the Allies. Allied educational training practices similarly adapted to new developments, along the way totally revising fleet operations with parallel developments in both the Combat Information Center and in their doctrine, training, and practices to get the most out of the new communications and sensor technologies.

In 1944, the Fast Carrier Task Force, under Admiral Marc Mitscher (known as Task Force 58 when part of Admiral Raymond Spruance's Fifth Fleet and Task Force 38 when led by Admiral William F. Halsey as part of the Third Fleet), began a series of softening-up missions aimed at weakening Japanese land-based airpower to limit Japan's ability to interfere with future amphibious invasions. With the possible exception of Admiral Mitscher, few commanders realized how powerful Task Force 58 had become. Though initially undertaken with trepidation, the raids proved to be successful beyond anything US planners had imagined, and changed the manner in which the war would be pursued.

The Japanese commanders saw the Marianas island group in the central Pacific, including Guam, Tinian, and Saipan, as the inner circle of defense. Land-based fighter and bomber aircraft on these islands controlled the sea lanes to Japan and protected the home islands. In late 1943 Japan's 'outer' defensive ring was punctured at the costly Battle of Tarawa, and in early 1944 the U.S. fleet continued on through the Marshalls in a steady progression across the islands of the Central Pacific. The Imperial Staff calculated the Marianas would be next to come under similar attack. American control of the Marianas would put the Japanese home islands within effective range of American bombers. If the Marianas came under attack, the Japanese navy could wait no longer. This would be their time to bring the US Navy into the long awaited decisive battle.

Though US planners, particularly Admiral Spruance, were wary of the Japanese trying to attack U.S. transports and newly landed forces, the Japanese were looking to engage and defeat Task Force 58, the major fighting unit of the US Navy. The Japanese had a number of advantages they hoped would turn the battle in their favor. Though outnumbered in ships and aircraft, they planned to supplement their carrier airpower with land-based aircraft. In addition, the Japanese aircraft had superior range, which could allow them to engage the American carriers beyond the range of American aircraft. Furthermore, with island bases in the area, the Japanese hoped to launch at distance, have their aircraft attack the US fleet and then land on island airfields. They then could shuttle back and attack again on the return flight. Thus the U.S. fleet would be in the position of receiving punishment without being able to deliver it. Lastly, the area was dominated by the easterly trade winds. Aircraft in those days needed a head wind blowing across the flight deck to enable the aircraft to launch. The easterly trade winds that dominated the Central Pacific seas meant that aircraft carriers would necessarily have to be steaming eastward to launch and recover aircraft. This meant that a fleet located to the west of the Marianas would necessarily be in position to initiate and break off the battle, placing the initiative in the hands of the Japanese.

In March 1944, the Commander of the Combined Fleet, Admiral Mineichi Koga, was killed when his aircraft flew into a typhoon and crashed. A new Commander-in-Chief of the Combined Fleet, Admiral Soemu Toyoda, was appointed. He continued the current work, finalizing the Japanese plans known as "Plan A-Go", or "Operation A-Go" The plan was adopted in early June 1944, then within weeks quickly put into place to engage the American fleet now detected heading for Saipan.

Initial stages
On June 12, 1944, U.S. carriers started a series of air strikes on the Marianas, convincing Admiral Toyoda that the U.S. was preparing to invade. This move came as a surprise; the Japanese had expected the next U.S. target to be farther to the south, either the Carolines or the Palaus, and had protected the Marianas with only 50 land-based aircraft. From June 13-15, American carriers conducted airstrikes while surface forces engaged in shore bombardment operations against the Marianas in preparation for the coming battle. On June 15, 1944, the first American troops went ashore, which marked the start of the invasion of Saipan.

Since control of the Marianas would place the Japanese home islands in range of the new American B-29 Superfortress strategic bombers, the IJN decided that the time for the long-awaited Kantai Kessen (decisive battle) had arrived. Toyoda immediately ordered a fleet-based counterattack, which would commit nearly all of the Japanese navy's serviceable ships to the coming engagement.

The Japanese fleet, commanded by Vice-Admiral Jisaburo Ozawa, consisted of three large fleet carriers (Taihō, Shōkaku, and Zuikaku), two converted carriers (Junyō and Hiyō), four light carriers (Ryūhō, Chitose, Chiyoda, and Zuihō), five battleships (Yamato, Musashi, Kongō, Haruna and Nagato), 13 heavy cruisers, 6 light cruisers, 27 destroyers, six oilers, and 24 submarines. The main portions of the fleet rendezvoused on June 16 in the western part of the Philippine Sea and completed refueling on June 17.

Ozawa commanded this force from his newly commissioned flagship, Taihō. In addition to extensive command facilities, reinforced torpedo blister, and large air group, Taihō was the first Japanese carrier to possess an armor-plated flight deck, designed to withstand multiple bomb hits with minimal damage.

At 1835 of 15 June a Japanese carrier and battleship force was sighted coming out of the San Bernardino Strait by submarine USS Flying Fish. An hour later USS Seahorse spotted a battleship and cruiser force steaming up from the south and located 200 miles east of the Philippine island of Mindanao. The submarine force was under orders to report sightings first, before attempting to attack. Thus Flying Fish waited till nightfall, then surfaced to radio in its report. Admiral Spruance, commander of the U.S. 5th Fleet was convinced that a major battle was at hand. He consulted with Admiral Chester Nimitz at Pacific Fleet Headquarters in Hawaii. He subsequently ordered Task Force 58, which had separated and sent two of its carrier task groups north to intercept aircraft reinforcements from Japan, to reform and move west of Saipan into the Philippine Sea. Admiral Jesse B. Oldendorf's force of eight older battleships and nearly two dozen smaller escort carriers were to remain near Saipan to support the landings and protect the invasion fleet. Task Force 58 was commanded by Vice Admiral Marc Mitscher aboard his flagship, USS Lexington of Task Group 58.3. Spruance, who exercised overall command of the U.S. 5th Fleet, flew his flag aboard the heavy cruiser USS Indianapolis, which was sailing in the outer defensive ring of Task Group 58.3.

Task Force 58 was made up of five task groups. Deployed in front of the carriers to act as an anti-aircraft screen was the battle group of Vice Admiral Willis Lee. Task Group 58.7 (TG-58.7), contained seven fast battleships (Washington (flagship), North Carolina, Indiana, Iowa, New Jersey, South Dakota and Alabama), and eight heavy cruisers (Baltimore, Boston, Canberra, Indianapolis, Wichita, Minneapolis, New Orleans, and San Francisco). Just north of them was the weakest of the carrier groups, Rear Admiral William K. Harrill's Task Group 58.4 of one fleet carrier and two light carriers: (Essex, Langley and Cowpens). To the east, in a line running north to south, were three groups, each containing two fleet carriers and two light carriers: Rear Admiral Joseph Clark's Task Group 58.1 (Hornet, Yorktown, Belleau Wood and Bataan); Rear Admiral Alfred Montgomery's Task Group 58.2 (Bunker Hill, Wasp, Cabot and Monterey) and Rear Admiral John W. Reeves's Task Group 58.3 (Enterprise, Lexington, San Jacinto and Princeton). These capital ships were supported by 13 light cruisers, 58 destroyers, and 28 submarines.

Shortly before midnight on June 18, Admiral Chester W. Nimitz sent Spruance a message from Pacific Fleet Headquarters in Hawaii indicating that a Japanese vessel had broken radio silence. The message intercepted was an apparent dispatch from Ozawa to his land-based air forces on Guam. A "fix" obtained by radio direction-finding gave a solution for the origination of the message at approximately 355 miles (562 km) west-southwest of Task Force 58. Though Mitscher considered whether the radio fix was part of a Japanese deception, as the Japanese were known to send a single vessel off to break radio silence, to mislead their adversaries about the actual location of the main force.

Mitscher realized that there was a chance of a night surface encounter with Ozawa's forces. Arleigh Burke, Mitscher's Chief of Staff and a former destroyer squadron commander, assumed Lee would welcome the opportunity, but discovered that Lee in no uncertain terms did not favor such an encounter. Experienced in the confusion that had been common place in the night actions of the Naval Battle of Guadalcanal, Lee was not enthusiastic about a night engagement with Japanese surface forces, believing that his crews were not adequately trained for such an action. Shortly after learning of Lee's opinion, Mitscher requested permission from Spruance to move Task Force 58 west during the night to reach a launch position at dawn that would allow for an maximum aerial assault on the enemy force.

After considering for an hour, the reply back came refusing Mitscher's request. Mitscher's staff was disappointed with Spruance's decision. On the situation, Captain Burke later commented: "We knew we were going to have hell slugged out of us in the morning. We knew we couldn't reach them. We knew they could reach us." Spruance's decision was influenced by his orders from Nimitz, who had made it clear that the protection of the invasion fleet was the primary mission of Task Force 58. Spruance had concerns that the Japanese would attempt to draw his main fleet away from the Marianas with a diversionary force, while slipping an attack force in to destroy the landing fleet. Locating and destroying the Japanese fleet was not his primary objective, and he was unwilling to allow the main strike force of the Pacific Fleet to be drawn westward, away from the amphibious forces. Mitscher accepted the decision without comment.

Spruance's decision in this matter, although subsequently criticized, was certainly justified; by this point in the war, it was well known that Japanese operational plans frequently relied on the use of decoys and diversionary forces. However, in this particular engagement (and in sharp contrast to the subsequent Battle of Leyte Gulf), there was no such aspect in the Japanese plan.

Before daybreak Spruance had suggested sending bombers to crater the airfields on Rota and Guam, but the contact-fused ordnance was largely used up, and Mitscher hoped to use the armour-piercing ordnance on the Japanese fleet. He ordered Spruance not to launch such strikes. As the morning broke, Task Force 58 launched search aircraft, combat air patrols and anti-submarine patrols, and then turned the fleet west to gain maneuvering room from the islands.

Early actions
The Japanese had already launched their morning search patrols using some of the 50 aircraft stationed on Guam, and at 05:50, one of these, a Mitsubishi Zero, found TF-58. After radioing his sighting of U.S. ships, he attacked one of the destroyers on picket duty and was shot down.

Alerted, the Japanese began launching their aircraft on Guam for an attack. These were spotted on radar by U.S. ships. A group of thirty F6F Hellcats were dispatched from the Belleau Wood to deal with the threat. The Hellcats arrived while aircraft were still launching from Orote Field. Minutes later, additional radar contacts were seen, which were later discovered to be the additional forces being sent north from the other islands. A huge battle broke out; 35 of the Japanese aircraft were shot down, for the loss of a single Hellcat. It was a pattern that would be repeated throughout the day. At 0957 large numbers of bogeys were picked up approaching the fleet. Mitscher said to Burke "Get those fighters back from Guam". The call "Hey Rube!" was sent out. The fleet held steady until 1023, when Mitscher ordered Task Force 58 to turn into the wind on course east-southeast, and ordered all fighter aircraft aloft, deployed in several layers of combat air patrol (CAP) to await the Japanese. He then put his bomber aircraft aloft to orbit open waters to the east to avoid the danger of a Japanese bomb strike into a hangar deck full of aircraft.

Japanese raids


The recall had been ordered after several ships in TF-58 picked up radar contacts 150 mi to the west around 10:00. This was the first of the raids from the Japanese carrier forces, with 68 aircraft. TF-58 started launching every fighter it could, and by the time they were in the air, the Japanese had closed to 70 mi. However, the Japanese began circling to regroup their formations for the attack. This 10-minute delay proved critical, and the first group of Hellcats met the raid, still at 70 mi, at 10:36. They were quickly joined by additional groups. Within minutes, 25 Japanese aircraft had been shot down, against the loss of only one U.S. aircraft.

The Japanese aircraft that survived were met by other fighters, and 16 more were shot down. Of the 27 aircraft which now remained, some made attacks on the picket destroyers USS Yarnall and USS Stockham but caused no damage. Between three and six bombers broke through to Lee's battleship group and commenced their attacks, one of which scored a direct hit on the main deck of USS South Dakota, which killed or injured over 50 men, but failed to disable her; USS South Dakota was the only American ship damaged in this attack. Not one aircraft of Ozawa’s first wave got through to the American carriers.

At 11:07, radar detected another, much larger attack. This second wave consisted of 107 aircraft. They were met while still 60 mi out, and at least 70 of these aircraft were shot down before reaching the ships. Six attacked Rear Admiral Montgomery’s group, nearly hitting two of the carriers and causing casualties on each. Four of the six were shot down. A small group of torpedo aircraft attacked Enterprise, one torpedo exploding in the wake of the ship. Three other torpedo-aircraft attacked the light carrier Princeton but were shot down. In all, 97 of the 107 attacking aircraft were destroyed.

The third raid, consisting of 47 aircraft, came in from the north. It was intercepted by 40 fighters at 13:00, while 50 mi out from the task force. Seven Japanese aircraft were shot down. A few broke through and made an ineffective attack on the Enterprise group. Many others did not press home their attacks. This raid therefore suffered less than the others, and 40 of its aircraft managed to return to their carriers.

The fourth Japanese raid was launched between 11:00 and 11:30, but pilots had been given an incorrect position for the US fleet and could not locate it. They then broke into two loose groups and turned for Guam and Rota to refuel. One group flying toward Rota stumbled upon Montgomery’s task group. Eighteen aircraft joined battle with American fighters and lost half their number. A smaller group of nine Japanese dive bombers of this force evaded U.S. aircraft and made attacks on the USS Wasp and the USS Bunker Hill, but failed to make any hits. Eight of these aircraft were shot down in the process. The larger group of Japanese aircraft had flown to Guam and were intercepted over Orote Field by 27 Hellcats while landing. Thirty of the 49 Japanese aircraft were shot down, and the rest were damaged beyond repair. Aboard the Lexington afterward, a pilot was heard to remark "Hell, this is like an old-time turkey shoot!"

Including the continued aerial slaughter over Orote Field, Japanese losses exceeded 350 planes on the first day of battle. American losses were relatively light, with about thirty planes being lost. Damage to American ships was minimal, and even the damaged South Dakota was able to remain in formation to continue her anti-aircraft duties.

Most of the Japanese pilots who successfully evaded the US fighter screens were aviators who were seasoned veterans of the six-month Japanese advance early in the Pacific war, the South Pacific campaign and survivors of the Battle of Midway.

Submarine attacks
Throughout the day, American scout aircraft had been unable to locate the Japanese fleet. However, two American submarines had already spotted Ozawa's carriers early that morning, and were about to provide a major assist to the Fast Carrier Task Force.

At 08:16 the submarine USS Albacore, which had sighted Ozawa’s own carrier group, had maneuvered into an ideal attack position; Lieutenant Commander James W. Blanchard selected the closest carrier as his target, which happened to be Taihō, the largest and newest carrier in the Japanese fleet and Vice Admiral Jisaburo Ozawa’s flagship. As Albacore was about to fire, however, her fire-control computer failed, and the torpedoes had to be fired “by eye”. Determined to go ahead with the attack, Blanchard ordered all six torpedoes to be fired in a single spread to increase the chances of a hit.

Taihō had just launched 42 aircraft as a part of the second raid when Albacore fired its torpedo spread. Of the six torpedoes fired, four veered off-target; Sakio Komatsu, the pilot of one of the recently launched aircraft, sighted one of the two which were heading for Taihō and dove his aircraft into its path, causing the torpedo to detonate prematurely. However, the sixth torpedo struck the carrier on her starboard side, rupturing two aviation-fuel tanks. After coming under depth charge attacks from the carrier's escorting destroyers, Albacore was able to escape with only minor damage.

Initially, the damage to Taihō seemed minor; the flooding was quickly contained and the carrier's propulsion and navigation were unaffected. Taihō quickly resumed regular operations; however, gasoline vapors from the ruptured fuel tanks began to fill the hangar decks, creating an increasingly dangerous situation on board.

Another submarine, USS Cavalla, was able to maneuver to an attack position on the 25,675-ton carrier Shōkaku by about noon. The submarine fired a spread of six torpedoes, three of which struck the Shōkaku on her starboard side. Badly damaged, the carrier came to a halt. One torpedo had hit the forward aviation fuel tanks near the main hangar, and aircraft that had just landed and were being refueled exploded into flames. Ammunition and exploding bombs added to the conflagration, as did burning fuel spewing from shattered fuel pipes. With her bows subsiding into the sea and fires out of control, the captain gave orders to abandon ship. Within minutes, total catastrophe struck the vessel. Volatile gas fumes had accumulated throughout the vessel, and when an aerial bomb exploded on the hangar deck, a series of terrific explosions simply blew the ship apart about 140 mi north of the island of Yap. The carrier rolled over and slid beneath the waves taking 887 navy officers and men plus 376 men of the 601st Naval Air Group, a total of 1,263 men in all, to the seabed. There were 570 survivors, including the carrier's commanding officer, Captain Hiroshi Matsubara. Futile attempts were made by destroyer JAPANESE DESTROYER Urakaze to destroy the submarine, but Cavalla escaped with relatively minor damage despite near misses from depth charges.

Meanwhile, Taihō was falling victim to poor damage control. On the orders of an inexperienced damage-control officer, her ventilation system had been operating at full-blast in an attempt to clear explosive fumes from the ship. This instead had the effect of spreading the vapors throughout Taihō, and essentially turned the entire carrier into a floating powder keg. At approximately 14:30, she suffered a series of catastrophic explosions caused by the accumulated fumes igniting near an electric generator on the hangar deck. After the first explosions, it was clear that Taihō was doomed, and Ozawa and his staff transferred to a nearby destroyer. Shortly thereafter, Taihō suffered a second series of catastrophic explosions, and sank shortly afterward. Of her complement of 1,751, a total of 1,650 crewmen were lost.

U.S. counterattack


TF-58 sailed west during the night to attack the Japanese at dawn. Search patrols were put up at first light.

Admiral Ozawa had transferred to the destroyer Wakatsuki after Taihō had been hit, but the radio gear onboard wasn't capable of sending the number of messages needed, so he transferred again, to the carrier Zuikaku, at 13:00. It was then he learned of the disastrous results of the previous day and that he had about 150 aircraft left. Nevertheless, he decided to continue the attacks, thinking there were still hundreds of aircraft on Guam and Rota, and started planning new raids for June 21.

The main problem for Task Force 58 was locating the enemy, who had been operating at a great distance. Early morning American searches on June 20 found nothing. An extra mid-day search flown by Hellcat fighter pilots also came back empty. Finally at 15:12 a garbled message from one of the Enterprise search planes indicated a sighting. At 15:40 the sighting was verified, along with distance, course and speed. The Japanese fleet was 275 miles out, moving due west at a speed of 20 knots. The Japanese were at the limit of the strike range of Task Force 58, and daylight was slipping away. Mitscher decided to launch an all out strike. With the first group up a third message came in, indicating the Japanese fleet were 60 miles farther out than previously indicated. The first launch would be at their limits of fuel, and would have to attempt landing at night. Mitscher canceled the second launch of aircraft, but chose not to recall the first launch. The Task Force 58 aviators arrived over the Japanese fleet just before sunset.

The fighter air cover Ozawa was able to put up would have been good by 1942 standards, but in 1944 the 35 or so fighters he had available to intercept the incoming U.S. attack were completely overwhelmed by the incoming 230 aircraft of Mitscher's attack. Though these few were skillfully handled and the Japanese antiaircraft fire was intense, the U.S. planes were able to press in on the attack.

The first ships sighted by the U.S. strike were oilers, and two of these were damaged so severely that they were later scuttled.

The carrier Hiyo was attacked and hit by bombs and aerial torpedoes from four Grumman Avengers from Belleau Wood. Hiyō was set afire after a tremendous blast from leaking aviation fuel. Dead in the water, she slipped stern first under the waves, taking the lives of 250 officers and men. The rest of her crew, about one thousand, survived to be rescued by Japanese destroyers.

The carriers Zuikaku, Junyō, and Chiyoda were damaged by bombs, as was the battleship Haruna. Twenty American aircraft were lost in this strike.

At 20:45, the first U.S. aircraft began to return to TF 58. Knowing his aviators would have difficulty finding their carriers, Mitscher decided to fully illuminate his carriers, shining searchlights directly up into the night, despite the risk of attack from submarines and night-flying aircraft. Picket destroyers fired starshells to help the aircraft find the task groups. Despite this, 80 of the returning aircraft were lost, some crashing on flight decks, the majority going into the sea. Many of their crews (approximately three quarters) were rescued over the next few days.

Japanese
That night, Admiral Ozawa received orders from Toyoda to withdraw from the Philippine Sea. U.S. forces gave chase, but the battle was over.

The four Japanese air strikes involved 373 carrier aircraft, of which 130 returned to the carriers, although many of these survivors were subsequently lost on board when the two carriers were sunk on the first day by submarine attacks. After the second day the losses totaled three carriers, more than 433 carrier aircraft, and around 200 land-based aircraft. Losses on the U.S. side on the first day were only 23 aircraft. The second day's airstrike against the Japanese fleet saw most of the aircraft losses for the U.S. Of the 215 aircraft launched on the strike, only 115 made it back. Twenty were lost to enemy action in the attack, while 80 more were lost when one by one they expended their fuel and had to ditch into the sea.

The losses to the already outnumbered Japanese fleet air arm were irreplaceable. The Japanese had spent the better part of a year reconstituting their carrier air groups, and the Americans' Fast Carrier Task Force had destroyed 90% of it in two days. The Japanese only had enough pilots left to form the air group for one of their light carriers. In the Battle of Leyte Gulf to follow a few months later, their carriers were used solely as decoys.

The Japanese military, which had shielded the Japanese public from the extent of their losses, continued this policy. Though the occurrence of the simultaneous Battle of the Philippine Sea and the Battle of Saipan were made known to the public, the extent of the disasters were withheld.

American
The American F6F Hellcat fighter proved a capable weapon. Its powerful engine generated superior speed, and its protection and firepower made it rugged and deadly. The Japanese were still flying the A6M Zero, which though highly maneuverable, was underpowered and fragile. In addition, the D4Y "Judy", though fast, was also fragile and easily set afire. The Japanese naval airmen were largely inadequately trained. The Japanese preparation programs could not replace the quality aviators lost during the past two years of the Pacific Campaign. Flying against the well trained and often veteran U.S. aviators, it was a one sided contest. The Americans lost fewer than two dozen Hellcats in air to air combat, and garnered nearly 480 Japanese kills, 346 of those carrier aircraft on 19 June alone.

Spruance's conservative battle plan, while not destroying all of the Japanese aircraft carriers, severely weakened the Japanese naval aviation forces by killing most of the remaining trained pilots and destroying their last operational reserves of naval aircraft. Without the time or resources to build sufficient aircraft and train experienced pilots, the surviving Japanese carriers were useless as weapons, a fact the Japanese recognized by using them as sacrificial decoys at Leyte Gulf. With the effective crippling of her best striking arm, Japan was increasingly forced to rely on land-based kamikaze suicide aircraft in a last-ditch effort to make the war so costly that the U.S. would offer peace terms (other than unconditional surrender).

Spruance was heavily criticized after the battle by many officers, particularly the aviators, for his decision to fight the battle cautiously rather than exploiting his superior forces and intelligence data with a more aggressive posture. By failing to close on the enemy earlier and more forcefully, his critics argue, he squandered an opportunity to destroy the entire Japanese Mobile Fleet. "This is what comes of placing a non-aviator in command over carriers" was the common refrain. Admiral John Towers, a naval aviation pioneer and Deputy Commander-in-Chief Pacific Fleet, demanded that Spruance be relieved. The request was denied by Admiral Nimitz.

In retrospect, it certainly is instructive to compare Spruance's caution (in particular, his suspicion of a diversionary force) with Admiral Halsey's headlong pursuit of an actual diversionary force four months later at the Battle of Leyte Gulf. There, Halsey's decision left the American invasion fleet, defended only by escort carriers and destroyers, open to an attack by a fleet of heavy Japanese surface units during the battle off Samar, creating a crisis in which the Americans narrowly averted a strategic disaster.

Although the American carrier aircraft strikes caused less destruction to enemy naval vessels than earlier battles, the air defense of Task Force 58 shattered the Japanese naval air arm, a blow from which it never recovered. Spruance was supported in his decision by Admirals Kelly Turner and Chester Nimitz, along with the most senior naval commander, the acerbic and highly demanding Admiral Ernest King, Chief of Naval Operations.