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“The Most Difficult Antiaircraft Problem Yet Faced By the Fleet”: U.S. Navy vs. Kamikazes at Okinawa

As U.S. Fifth Fleet naval and amphibious forces, under the command of Admiral Raymond Spruance, prepared to execute Operation Iceberg, the invasion of Okinawa, in early 1945, the land-based air forces of the Imperial Japanese Army (IJAAF) and Navy (IJNAF) posed the primary threat they faced. The U.S. Navy had decisively defeated Japanese naval airpower and seapower in the battles of the Philippine Sea (June 1944) and Leyte Gulf (October 1944). Despite the precipitous decline of its remaining airpower relative to increasing American aerial advantages in skill, technology, and numbers, however, Japan’s desperate resort to kamikaze (“divine wind”) aerial suicide tactics proved grimly effective.

Japan initiated kamikaze attacks in response to the invasion of the Philippine Islands by U.S. military forces in October 1944. Although hints about adopting suicide tactics had been picked up before then, their use on a wide scale came as a surprise. The fanatical resolve of Japanese pilots turned their aircraft into human guided missiles, which struck or damaged 130 U.S. and Allied combat vessels during the campaign, sinking 20, and killing at least 1,400 Sailors.[1] While these results did not prevent Japan’s defeat in the Philippines, they exceeded considerably what the Japanese achieved with orthodox air tactics alone. This guaranteed the greater use of kamikazes going forward.

The Navy’s robust fleet air defense capability proved overwhelmingly effective against conventional Japanese air attacks but struggled to cope fully with kamikaze strikes. As the Headquarters of the Commander in Chief of the U.S. Fleet stated in April 1945:

The suicide attack represents by far the most difficult antiaircraft problem yet faced by the fleet. The psychological value of AA, which in the past has driven away a large percentage of potential attackers, is inoperative against the suicide plane. If the plane is not shot down or so severely damaged that its control is impaired, it almost inevitably will hit its target.[2

Japan’s defeat in the Okinawa campaign and its eventual surrender has somewhat obscured the desperate character of the battle between the Navy and the kamikazes. American and Allied pilots and Sailors met the Japanese challenge with courage and steely determination. The fight boiled down to a contest between the Navy leveraging its skill, material, and technology to locate and destroy suicide attackers and Japanese resourcefulness in getting them close enough to exploit the advantage of terminal human guidance. In the end, the Navy slowed the kamikazes, but could not completely stop them. Despite the sacrifice and damage inflicted, suicide tactics failed to reverse Japan’s fortunes or prevent its ultimate downfall.

U.S. Fleet Air Defense

By 1945, the U.S. Navy had developed a multilayer fleet anti-air defense that integrated radar, fighter combat air patrols (CAP), and antiaircraft guns. Most Navy combat ships possessed SK air search radar that could detect incoming aircraft, though not their altitude, to a range of 75–100 nautical miles. The use of destroyers along early warning picket lines extended this capability out to 150 miles. All carriers and many battleships, cruisers, and destroyers had shorter range SM or SP radar sets capable of identifying target direction and altitude, and fighter direction centers to vector CAP fighters to intercept.

The fast carrier task forces maintained continuous CAP and all major landing operations enjoyed extended air coverage from escort carriers or land-based air units. Navy pilots averaged two years of training and 300 hours of flight time by mid-1944 before joining a carrier squadron, far exceeding the standards of their opponents.[3] The fighter groups of the fleet (36–40 planes) and light carriers (21–24 planes) were equipped with Grumman F6F Hellcats or Vought F4U Corsairs, technologically superior to the IJNAF’s Mitsubishi A6M Zero-Sen Type 0 Navy carrier fighters and the IJAAF’s Nakajima Ki-43 Hayabusa Type 1 fighters (Oscar). Most of the escort carrier fighter squadrons fielded 16–18 Grumman FM-2 Wildcats, an improved version of the older F4F Wildcat.[4]

The Navy had significantly improved the firepower and accuracy of its antiaircraft weaponry throughout the fleet since the war began. On most warships, 5-inch/38 dual-purpose guns superseded 5-inch/25 and 3-inch guns for long-range defense, while 40-milimeter and 20-milimeter automatic cannon batteries replaced 1.1-inch guns and .30 and .50 caliber machine guns for short-range coverage. The older weapons were used to arm merchant and auxiliary vessels. Radar and computer-equipped dual-purpose fire directors (Mk. 19, Mk. 33, Mk. 37, and Mk. I analog computer) were installed that calculated range and bearing to automatically guide the 5-inch guns onto target. Perhaps more importantly, these guns were armed with VT “variable time” shells incorporating tiny radar proximity fuses—which could damage or destroy a plane without hitting it—in increasing quantities. Manual and radar-guided antiaircraft gun directors (Mk. 49, Mk. 51) were also added for the 40mm batteries that allowed them to be centrally controlled. 20mm batteries received Mk. 14 gyroscopically-stabilized gunsights that computed elevation and traverse angles to lead incoming targets.[5]

By 1945, the number of antiaircraft guns per ship had increased drastically as well, and averaged the following:[6]

Battleships

165 barrels

10 5-inch/38 twins; 20 40-mm quads; 49 20-mm singles, and 8 20-mm twins

Heavy cruisers

83 barrels

6 5-inch/38 twins; 12 40-mm quads; 23 20-mm singles

Light cruisers

50 barrels

6 5-inch/38 twins; 4 40-mm quads; 6 40-mm twins; 10 20-mm singles

Large cruiser

102 barrels

6 5-inch/38 twins; 14 40-mm quads; 34 20-mm singles

Fleet aircraft carriers

136 barrels

4 5-inch/38 twins; 4 5-inch/38 singles; 17 40-mm quads; 56 20-mm singles

Light aircraft carriers

40 barrels

2 40-mm quads; 9 40-mm twins; 8 20-mm twins

Escort aircraft carriers

37 barrels

1 5-inch/38 single; 8 40-mm (wins; 20 20-mm singles

Large aircraft carriers

158 barrels

18 5-inch/54 singles; 21 40-mm quads; 28 20-mm twins

Destroyers

42 barrels

3 5-inch/38 twins; 3 40-mm quads; 2 40-mm twins; 10 20-mm twins


Battle of the Philippine Sea, June 1944

A view of the antiaircraft suite on the starboard side of the Essex-class aircraft carrier Lexington (CV-16). On the lower right is a Bofors 40-millimeter quadruple gun mount; in the center are a pair of turrets mounting dual 5-inch/38 dual purpose guns; and along the deck to the left is a gallery lined with Oerlikon 20-millimeter guns. (80-G-236955)


In order to maximize this firepower, the Navy adopted circular task group antiaircraft dispositions with the highest value ships in the center and the screen and escorts deployed in concentric layers for an all-around defense in depth. Per doctrine, 5-inch batteries engaged attacking planes first at ranges of 12,000 yards or more using a high percentage of VT shells. These guns were expected to be the primary aircraft killers due to their hitting power, special ammunition, and radar direction. The 40mm and 20mm guns provided close-in defense with massed automatic and aimed fire beginning at 3,000-3,500 yards.[7]

This combination proved exceptionally effective during the Battle of the Philippine Sea in June 1944, where the fast carrier Task Force (TF) 58’s experienced and well-trained fighter pilots downed an estimated 243 of 373 attacking Japanese carrier aircraft against 15 air-to-air combat losses of their own in one day alone. The massive volume of antiaircraft fire protecting TF 58 shot down or drove off the few attackers that slipped past the CAP, limiting damage to a single bomb hit on battleship South Dakota (BB-57) and a handful of near misses.[8]

Kamikazes in the Philippines

Vice Admiral Onishi Takijiro, commander of the IJNAF First Air Fleet based in the Philippines, initiated large scale suicide attacks after strikes by the fast carriers of TF 38 (as they were designated while assigned to Admiral William F. Halsey’s Third Fleet) reduced his command to 40 operational aircraft. Two dozen IJNAF pilots volunteered to form the initial Tokubetsu Kōgekitai (tokko), or Special Attack Unit, soon known as kamikaze, on 19 October 1944. On 25 October, a dozen pilots flying Zero fighters modified to carry 250-kilogram (550 pound) bombs targeted Vice Admiral Thomas C. Kinkaid’s Seventh Fleet with the first successful group attacks. They sank the escort carrier St. Lo (CVE-63), killing or mortally wounding 126 crew members, and damaged Kalinin Bay (CVE-68) (seven dead, 53 wounded), Kitkun Bay (CVE-71) (one dead, 16 wounded), Santee (CVE-29) (16 killed, 27 wounded), Suwannee (CVE-27) (hit on 25 and 26 October, 107 dead, 160 wounded), and White Plains (CVE-66) (11 wounded), several of which had survived attack by Japanese warships during the Battle of Samar earlier in the morning.[9]

The Japanese heavily reinforced their air units in the Philippines and the IJAAF formed tokkos of its own. They mounted continuous attacks throughout landing operations against Leyte, Mindoro, and Luzon. Although all types of aircraft were eventually used for kamikaze missions, most of the early attacks employed single-engine fighters and attack planes. Realizing the need to preserve their pool of trained pilots, they began recruiting candidates just to fly kamikaze missions. In mid-1944, Japanese carrier air crews possessed just two to six months of training. This declined through end of the war, when Japanese aviators averaged only 100 hours of flight experience. Kamikaze pilots were given just 30 to 50 hours of flight training.[10]

They sortied in small groups of five or six planes, with three kamikazes and two or three conventional escorts. Approaches were made from high or low altitude and over land to exploit known weaknesses in American radar coverage. The configuration of shipboard antennae left gaps overhead and at low altitude. Meter-wavelength SK air search radar proved prone to self-interference caused by reflection off the sea surface and land, which caused blind spots. This made it difficult to track inbound contacts continuously. The centimeter-wavelength SM and SP fighter direction radars lacked the range to do air search.[11] Attackers also trailed returning American air strikes if possible and spoofed electronic identification friend or foe (IFF) signals.

As a result, kamikaze pilots often evaded interception by the CAP. Both the suicide planes and their escorts sought to break contact if engaged by American fighters. Wartime analysis estimated that CAP intercepted and splashed or drove off 60 percent of all attacking aircraft. A Navy study done in 1970 suggested this figure likely averaged closer to 45 percent during the Philippines campaign. While chances of successful of attacks detected over open water were about 60 percent, sorties over or near land reduced the probability to 30 percent.[12]

Typically forming up just outside 5-inch gun range for 10–15 minutes to select individual targets—sometimes allowing pursuing CAP to catch them—surviving kamikaze groups split up for final approach. High altitude attacks used the sun or clouds as cover, beginning a shallow angle (20–30 degrees) descent about 6,000–8,000 yards out. Some engaged in aerobatics. After closing to 1,500–2,000 yards, they engaged in terminal power dives up to 50 degrees, with little or no evasive maneuver, counting on speed to evade antiaircraft fire before impact. Low altitude approaches skimmed in 50–100 yards above the water; some closed to 1,000 yards before climbing sharply to 500 yards in altitude before diving sharply into their targets, other simply flew directly into the sides of ships.[13]


Typical Japanese high and low altitude kamikaze attack patterns. (NHHC)


Typical Japanese high and low altitude kamikaze attack patterns. (NHHC)

Typical Japanese high and low altitude kamikaze attack patterns. (NHHC)


Even with early warning and heavy CAP, kamikazes that penetrated to their target areas were often able to achieve tactical surprise due to a lack of coordination between shipboard fighter direction and search range and fire control radars. Incoming attackers were sighted equally often by lookouts and radar, but frequently too close to give effective warning. The average range Navy ships engaged kamikazes was 5,700 yards, while targeted ships did not open fire until 4,000 yards, well within the range of the 5-inch batteries and nearly at the effective range of the 20mm and 40mm guns.

The shortened range and reaction time diminished the effectiveness of the 5-inch guns and their lethal VT ammunition. Their fire control computers could not keep up with rapidly closing targets and the limited time for engagement reduced the number of shells fired. This left the burden of point defense to the 40mm and 20mm batteries. These guns were credited with 46.8 percent and 31.8 percent of the kamikazes downed by antiaircraft fire, respectively, while the 5-inch guns claimed 15.8 percent (VT fuzes accounted for 44 percent of that total).[14]

An estimated 650 IJNAF and IJAAF aircraft were expended in kamikaze sorties between 25 October 1944 and late-January 1945, when the remaining air units were evacuated from the Philippines.[15] Of 364 kamikazes that appeared over U.S. and Allied ships, antiaircraft guns claimed 231 kills and deflections (including the near misses), a success rate of 64 percent. However, 115 kamikazes hit ships (32 percent) and 56 more crashed close enough to cause damage (hits + near misses=47 percent). For comparison, 1,092 conventional attackers were also fired upon, of which 156 (14 percent) were shot down. Only 23 scored hits on ships (1.3 percent).[16]

Out of the 130 U.S. and Allied ships hit, the largest to sink were two escort carriers and three destroyers. However, tokko attacks damaged six fleet, two light, and 10 escort carriers; five battleships; one U.S. and two Australian heavy cruisers, six light cruisers; and 25 and one Australian destroyer.[17] This toll was not sufficient to prevent the Allies from retaking the Philippines, but it did show that Japanese airpower remained a formidable opponent.


USS Columbia (CL-56)


USS Columbia (CL-56)

Two photographs showing the kamikaze that struck the light cruiser Columbia (CL-57) on 6 January 1945, during the Lingayen Gulf operation. This plane hit the main deck by the after gun turret, causing extensive damage and casualties. (NHHC photographs, NH 79449 and NH 79450)


Kamikazes at Okinawa

The launch of Operation Iceberg at the end of March prompted an all-out Japanese effort to thwart it. The defense plan, Ten-Go (Operation “Heaven”), emphasized IJAAF and IJNAF attacks on the invasion force, but the crux of the operation rested on massed tokko raids (called kikisui, or “floating chrysanthemum”). Imperial Japanese Army forces on Okinawa prepared extensive defenses, planning to hold out to the end and force the enemy ships to expose themselves to these attacks for as long as possible.[18] As a result, U.S. naval forces fired on more enemy aircraft during the Battle of Okinawa than in any other campaign during World War II. U.S. ships engaged in more antiaircraft actions in April 1945 than in any other month of the war.[19]

As it prepared for this operation, the Navy carefully reviewed its experience with the kamikazes to develop better ways to counter them. The Antiaircraft Operations Research Group (AAORG), established in October 1944 within the Navy’s new Operations Research Group (ORG), and the Special Defense Section in Admiral Chester Nimitz’s Pacific Fleet headquarters collected action reports from the fleet to examine all aspects of U.S. and Japanese air attack and defense. Their findings and recommendations were disseminated throughout the fleet. AAORG analysts suggested tactics to improve the probability of CAP interceptions, and that larger ships should employ radical maneuvers to avoid kamikaze strikes, while smaller ships refrain from doing so to improve the stability and aim of their antiaircraft guns. They also determined that ships were safer presenting their beams to high-angle attackers, while turning into or away from low-angle approaches.[20]

Another tactic, the “big blue blanket,” emphasized offensive action against Japanese airpower. In the lead-up to Operation Detachment, the invasion of Iwo Jima, Task Force 58 raided airfields in the Japanese home islands. Between 16–17 February 1945, 11 fleet and five light aircraft carriers flew 2,761 sorties which claimed the destruction of 500 enemy aircraft on the ground and in the air.[21] The Japanese managed only one kamikaze raid on forces supporting the subsequent Iwo Jima landings. On 21 February 1945, they struck six ships, sinking the escort carrier Bismarck Sea (CVE-95), killing 318 Sailors; and damaging fleet carrier Saratoga (CV-3), leaving 123 dead; and inflicting minor damage on Lunga Point (CVE-94) and three smaller vessels.[22]

TF 58 again raided Japanese airfields on Kyushu on 18–19 March 1945, in preparation for Operation Iceberg, destroying an estimated 528 enemy aircraft in the air and on the ground. It was joined by TF 57, a British carrier force, which attacked Japanese airbases in Formosa in late March and early April, and later joined TF 58 off Okinawa. Over the successive weeks, six British ships were hit by kamikazes, damaging four British carriers (two were struck twice), a heavy cruiser, and sinking a minesweeper. Their carriers featured armored flight decks and they sustained minimal damage, allowing flight operations to quickly resume. This protection limited their losses to 20 British sailors killed. The availability of TF 57 largely compensated for the absence of damaged U.S. carriers.[23]

An innovation adopted for Iceberg consisted of a perimeter of picket destroyers surrounding Okinawa to provide early warning of incoming aircraft. The proportion of fighters in the carrier air groups constantly increased until each fleet carrier embarked 70–90 fighters and escort carriers up to 24.[24] Efforts were made to speed up antiaircraft fire response. Communication procedures between radar operators and fighter directors were standardized and practiced. On many ships, control of the 5-inch batteries could be shifted to manual control or auxiliary directors to permit rapid engagement on short notice. The 20mm and 40mm guns could be released to sector control, and authorized to engage without good targeting solutions and to flood the air with area fire.[25]


Japanese Zero diving

A Japanese Zero diving on the light aircraft carrier Belleau Wood (CVL-24). It crashed into the water 50 yards off the carrier’s starboard side. (U.S. Naval Academy Digital Collection)


The character of the Japanese threat evolved as well. Training aircraft were incorporated into the tokkos, bolstering Japan’s kamikaze strength. These light monoplane and biplane aircraft carried less ordnance than combat planes, which reduced their individual lethality, but they were easier for barely trained suicide pilots to fly. IJNAF Yokosuka MXY-7 Ohka (cherry blossom”) rocket-powered planes developed in 1944 were also introduced. Powered by three engines and carried to the target by twin-engine bombers, they could reach 400 miles per hour and carried 2,600-pound warheads. Japanese radar snoopers aggressively probed the destroyer picket line, seeking gaps and weak points in the coverage. Attacks were increasingly timed to arrive over targets at dusk and dawn, and eventually at night.[26]

The kamikaze response at Okinawa began slowly, with a trickle of attacks beginning in late March. One of these hit Admiral Spruance’s flagship, the heavy cruiser Indianapolis (CA-35), on 31 March, killing nine crewmembers and forcing the ship to return to the U.S. for repair. The first and largest kikisui raid took place on 6–7 April 1945, consisting of 230 IJNAF and 125 IJAAF kamikazes and 340 conventional attackers and escorts. They managed to score hits on 33 ships, sinking a destroyer and three smaller ships. They damaged fleet carrier Hancock (CV-19), (62 killed and 71 wounded) severely enough to require repair in the U.S., light carrier San Jacinto (CVL-30) (no casualties), battleship Maryland (BB-46) (10 killed, 37 injured, and 6 missing); 11 destroyers, and 3 destroyer escorts. Nine more kikisui raids followed, none as large as the first. Three more occurred in April (12–13, 15–16, 27–28); four in May (3–4, 10–11, 24–25, 27–28), and two in June (3–7, 21–22). Altogether, the kikisui expended about 1,500 kamikaze planes, and about 400 more were used in small group attacks.[27]


antiaircraft fire from ships of TF 38

Under antiaircraft fire from ships of TF 38, a kamikaze exploded in mid-air as it approached an Essex-class aircraft carrier. A destroyer can be seen closing in the foreground. (U.S. Naval Academy Digital Collection)


Inexperienced and barely trained tokko pilots tended to attack the first ships they encountered, which at Okinawa were the picket destroyers. They sank 11 destroyers and damaged 63 more during the campaign. By mid-April 1945, the picket stations were reinforced to include a destroyer or destroyer-minesweeper with a fighter-director team embarked, a second destroyer to “ride shotgun,” one or more landing craft, and a two-plane CAP. The experiences of Pringle (DD-477), hit and sunk by a kamikaze, with the loss of 62 killed and 113 wounded, and Laffey (DD-724) surviving hits by four bombs and five kamikazes, at the cost of 32 dead and 71 wounded, both on 16 April, were horrifyingly frequent.[28]

The Ohkas proved ineffective. Their first attempted use reportedly occurred on 21 March, but all 16 bombers carrying them were shot down by Navy fighters before they could be launched. It is not known how many reached combat, but only 13 were spotted in flight. Difficult to pilot, nine missed and just 4 hit ships. Only one managed to hit and sink a ship, destroyer Mannert L. Abele (DD-733) on 12 April, killing 84 Sailors.[29]

While the radar pickets did an excellent job of providing early warning of incoming strikes and vectoring CAP to interceptions about 60 percent of the time, a large fraction of attackers still managed to get through. Radar provided the Navy with a great advantage, but it remained a new and relatively immature technology, complicated to maintain and tricky to use effectively. An analysis revealed problems with radar stations correctly identifying target altitude. Errors as small as 1,000 feet could allow CAP to miss enemy aircraft. Inspections found that many radars gave imprecise readings due to misadjusted antennae and inadequately trained operators.[30] The slow, wood and fabric biplane trainers presented air defense problems of their own. They were difficult to spot by radar until close to their targets, surprisingly nimble, and nearly as hard to hit with antiaircraft fire as combat planes.[31]

The kamikazes that reached their target continued to achieve tactical surprise. At Okinawa, average antiaircraft engagement ranges actually shrank to 4,400 yards and 3,700 yards for ships under attack. These averages were somewhat skewed, as combat vessels increased their average range to 6,400 yards while auxiliary and cargo types averaged only 2,800 yards. As a result, 80 percent of the kamikazes shot down by antiaircraft fire fell to the 40mm and 20mm guns and only 15 percent to the 5-inch batteries.[32] The strain of the constant vigil exacted an emotional toll on top of the physical one, sapping the energy and morale of ship’s crews.


 kamikaze attack

A diving kamikaze attack under fire from an Essex-class aircraft carrier during the Okinawa campaign. (U.S. Naval Academy Digital Collection)


In addition to conventional attacks, IJNAF and IJAAF pilots flew 1,900 kamikaze sorties in the Okinawa campaign before the Japanese curtailed the attacks in July to preserve their remaining aircraft for homeland defense. They lost at least 3,000 planes in combat and 7,000 to all causes. Although rudimentary pilot training, inferior aircraft, and improved American defense reduced the effectiveness of the kamikazes per sortie compared with the Philippines, increased attacks resulted in more Allied ships sunk and damaged.[33]

Kamikaze pilots managed to sink 26 U.S. and Allied ships and damage 225 others during the Okinawa campaign, killing at least 3,389 Americans (out of 36 sunk and 368 damaged by all causes, killing 4,907 Sailors and wounding 4,874 more). Of 793 kamikazes that attacked U.S. and Allied ships, 181 hit (23 percent) and 95 achieved damaging near misses (12 percent)—517 missed completely.[34] No ship larger than a destroyer sank; 86 percent of suicide attacks targeted destroyers or smaller vessels. The tokkos nevertheless damaged eight fleet and light carriers, four escort carriers, ten battleships, five cruisers, and 63 destroyers. Several were knocked out for the remainder of the war.[35]

The steady stream of attacks and losses strained American military and political leaders. President Franklin Roosevelt expressed to British Prime Minister Winston Churchill in January 1945 his concern over the casualties the kamikazes were inflicting on Allied ships and his declining hopes for an early end to the war. Both Spruance and Nimitz, normally stoic, expressed uncharacteristic frustration with the perceived slow pace of the U.S. Army in defeating the Japanese on Okinawa. Nimitz threatened to replace the Army general in command if his forces did not advance soon, an act he did not carry through on. He later stepped in to quell public concern over interservice conflict. Spruance mused to his chief of staff whether the Army cared about the Navy’s losses in ships and personnel. Although not scheduled to relinquish command of Fifth Fleet until after the campaign ended, Nimitz directed Spruance and his exhausted staff to change places with Halsey and his Third Fleet in May.[36] Third Fleet continued to cover operations on Okinawa until the ground fighting ended on 22 June.

Epilogue

The last ship sunk by kamikaze was destroyer Callaghan (DD-792) on 29 July, killing 47 of her crew, and the last ship hit was attack personnel transport La Grange (APA-124) on 13 August, which left 21 Sailors dead and 89 wounded. Four U.S. destroyers, 100 miles south of Honshu, Japan, shot down a lone Yokusuka D4Y Judy dive bomber on 15 August in the final antiaircraft action of World War II.[37]

Both the Allies and the Japanese understood the effectiveness of the kamikaze offensive in similar terms. IJNAF planners estimated that 1 in 6 (17 percent) tokko plane sorties would hit ships (IJAAF staff believed more optimistically that 1 in 3 would succeed). Drawing on AAORG analyses, the ratio of hits to sorties in the Philippines was 17.7 percent (115/650) and 9.5 percent (181/1,900) at Okinawa. These figures rose to 26 percent (171/650) and 14.5 percent (276/1,900) when damaging near misses were added in.[38]

The table below tallies the outcome of all of the attempted attacks definitely identified as kamikazes on Navy and Allied ships by month in 1944–1945. A kamikaze pilot that reached the target area and successfully commenced an attack stood almost a 1 in 2 (47.4 percent) chance of hitting or damaging a ship.[39]

While successful (certainly more so than orthodox air strikes), kamikaze tactics were not decisive. The Japanese resigned themselves to exploiting one remaining means of staving off utter defeat, despite the brutal cost. This willingness to sacrifice instilled a dread in their American opponents which technological superiority and resolve could not completely foreclose. The cost in casualties inflicted by the kamikazes deeply disturbed American leaders who were keenly aware that the kamikaze threat could be defeated, but not ended. This uneasiness contributed to deep concerns over the prospects of invading the Japanese home islands later in 1945. Post-war estimates credited the Japanese with more than 10,000 aircraft and the intent to commit them all to homeland defense.[40] Fortunately, this final test did not come to pass.

— Shawn R. Woodford, Ph.D., Historian, NHHC Histories and Archives Division, June 2020

*****

[1] Robert Cressman. Official Chronology of the U.S. Navy in World War II (1999); Dictionary of American Naval Fighting Ships (DANFS), Naval History & Heritage Command; Richard B. Frank. Downfall: The End of the Imperial Japanese Empire. New York: Random House, 1999, 180.

[2] Headquarters of the Fleet, U.S. Navy, “Antiaircraft Action Summary: Suicide Attacks, April 1945,” COMINCH P-009, 30 April 1945.

[3] Nicolai Timenes, Jr. “Defense Against Kamikaze Attacks in World War II and its Relevance to Anti-Ship Missile Defense, Volume I: An Analytical History of Kamikaze Attacks against Ships of the United States Navy during World War II.” Operations Evaluation Group, Center for Naval Analyses, Study 741. Monterey, CA, 1970, 27.

[4] Samuel Eliot Morison. History of United States Naval Operations in World War II, Vol. XII: Leyte, June 1944–January 1945. Boston: Little, Brown and Company, 1958, Appendices; Samuel Eliot Morison. History of United States Naval Operations in World War II, Vol. XIV: Victory in the Pacific, 1945. Boston: Little, Brown and Company, 1960. Appendices.

[5] Headquarters of the Commander in Chief, U.S. Fleet (COMINCH), “Antiaircraft Action Summary: World War II,” Information Bulletin No. 29, 8 October 1945, Ch. IV.

[6] COMINCH, “Antiaircraft Summary-World War II,” 15.

[7] COMINCH, “Antiaircraft Summary-World War II,” Ch. III.

[8] Timenes, “Defense Against Kamikaze Attacks in World War II,” 35–37.

[9] John Prados. Combined Fleet Decoded: The Secret History of American Intelligence and the Japanese Navy in World War II. Annapolis, Md.: Naval Institute Press, 1995, 618–625, 688–689.

[10] COMINCH, “Antiaircraft Action Summary: Suicide Attacks, April 1945,” Ch. III-3; OEG-CAN, 27.

[11] Kent G. Budge. “Radar,” Pacific War Online Encyclopedia, accessed 20 June 2020.

[12] COMINCH, “Antiaircraft Action Summary: Suicide Attacks, April 1945,” Ch. I-3, Ch. IV-5-6; Timenes, “Defense Against Kamikaze Attacks in World War II,” 73–74.

[13] COMINCH, “Antiaircraft Action Summary: Suicide Attacks, April 1945,” Ch. III.

[14] Timenes, “Defense Against Kamikaze Attacks in World War II,” 76.

[15] Timenes, “Defense Against Kamikaze Attacks in World War II,” 51.

[16] COMINCH, “Antiaircraft Action Summary: Suicide Attacks, April 1945,” Ch. II-1-2; Headquarters of the Commander in Chief, U.S. Fleet, “Antiaircraft Action Summary: World War II, October 1945,” Information Bulletin No. 29, 8 October 1945, 16.

[17] Prados, Combined Fleet Decoded, 688; Cressman, Official Chronology of the U.S. Navy in World War II; DANFS.

[18] Roy E. Appleman, James M. Burns, Russell A. Gugeler, John Stevens. The War in the Pacific: Okinawa: The Last Battle. Washington, D.C.: Center of Military History, U.S. Army, 1948.

[19] COMINCH, “Antiaircraft Summary-World War II,” Ch. V.

[20] Admiral Ernest J. King established ORG under the Readiness Division of his own Headquarters of the Commander in Chief of the U.S. Fleet from the Antisubmarine Warfare Operations Research Group (AWORG). ASWORG had been administered by the Office of Scientific Research and Development, but reported to Tenth Fleet. By 1944, many of its personnel had shifted to work on other questions as the Allies secured victory in the Battle of the Atlantic. Charles R. Shrader, History of Operations Research in the United States Army, Vol. 1: 1942–1962 (Washington, D.C.: Office of the Deputy Undersecretary of the Army for Operations Research, United States Army, 2006), 22–23; Keith R. Tidman, The Operations Evaluation Group: A History of Naval Operations Analysis (Annapolis, MD: Naval Institute Press, 1984),  85–87.

[21] Timenes, “Defense Against Kamikaze Attacks in World War II,” 49.

[22] Cressman, Official Chronology of the U.S. Navy in World War II; DANFS.

[23] Timenes, “Defense Against Kamikaze Attacks in World War II,” 55–56.

[24] Timenes, “Defense Against Kamikaze Attacks in World War II,” 66.

[25] Timenes, “Defense Against Kamikaze Attacks in World War II;” Headquarters of the Commander in Chief, U.S. Fleet, “Anti-Suicide Action Summary, August 1945,” COMINCH P-0011, 31 August 1945, 9.

[26] Timenes, “Defense Against Kamikaze Attacks in World War II,” 54, 57–59; Headquarters of the Commander in Chief, U.S. Fleet, “Battle Experience: Radar Pickets and Methods of Combating Suicide Attacks Off Okinawa, March-May 1945,” Information Bulletin No. 24, 20 July 1945; Headquarters of the Commander in Chief, U.S. Fleet, “Anti-Suicide Action Summary, August 1945,” COMINCH P-0011, 31 August 1945, 5–8.

[27] Timenes, “Defense Against Kamikaze Attacks in World War II,” 52, 54–55.

[28] Timenes, “Defense Against Kamikaze Attacks in World War II,” 62.

[29] Timenes, “Defense Against Kamikaze Attacks in World War II,” 58–59.

[30] Timenes, “Defense Against Kamikaze Attacks in World War II,” 62

[31] COMINCH, “Anti-Suicide Action Summary, August 1945,” 8–9.

[32] Timenes, “Defense Against Kamikaze Attacks in World War II,” 72–73.

[33] Timenes, “Defense Against Kamikaze Attacks in World War II,” 54–55.

[34] COMINCH “Antiaircraft Action Summary: World War II, October 1945,” 16–17.

[35] United States Strategic Bombing Survey. The Campaigns of the Pacific War. Washington, D.C.: U.S. Government Printing Office, 1946, 331; Prados, Combined Fleet Decoded, 718.

[36] Richard Hulver and Martin R. Waldman, "Battle of Okinawa: Historic Overview & Importance." Naval History and Heritage Command, 13 May 2020, accessed 12 June 2020.

[37] COMICH, “Antiaircraft Action Summary: World War II, October 1945,”4.

[38] Frank, Downfall, 184.

[39] These numbers do not include kamikazes shot down by CAP or antiaircraft fire before they attempted a suicide attack. COMINCH, “Antiaircraft Action Summary: World War II, October 1945.” The table has been modified to reflect the list of ships sunk by kamikazes compiled by Bill Gordon from Navy and Japanese sources. Bill Gordon, “47 Ships Sunk by Kamikaze Aircraft,” kamikaze images. Accessed 10 June 2020.

[40] Frank, Downfall, 182–187.

Published: Thu Jun 18 18:02:44 EDT 2020