Definition and etymology

History
Prior to the formation of kamikaze units, deliberate crashes had been used as a last effort when a pilot's plane was severely damaged and he did not want to risk being captured — this was the case in both the Japanese and Allied air forces. According to Axell & Kase, these suicides "were individual, impromptu decisions by men who were mentally prepared to die." and official Japanese accounts of Arima's attack bore little resemblance to the actual events.
On October 17, 1944, Allied forces assaulted Suluan Island, beginning the Battle of Leyte Gulf. The Imperial Japanese Navy's 1st Air Fleet, based at Manila was assigned the task of assisting the Japanese ships which would attempt to destroy Allied forces in Leyte Gulf. However, the 1st Air Fleet at that time only had 40 aircraft: 34 Mitsubishi Zero carrier-based fighters, three Nakajima B6N torpedo bombers, one Mitsubishi G4M and two Yokosuka P1Y land-based bombers, with one additional reconnaissance plane. The task facing the Japanese air forces seemed impossible. The 1st Air Fleet commandant, Vice Admiral Takijiro Onishi decided to form a suicide attack force, the Special Attack Unit. In a meeting at Mabalacat Airfield (known to the U.S. military as Clark Air Base) near Manila, on October 19, Onishi told officers of the 201st Flying Group headquarters: "I don't think there would be any other certain way to carry out the operation [to hold the Philippines], than to put a 250 kg bomb on a Zero and let it crash into a U.S. carrier, in order to disable her for a week."

Background
Commander Asaiki Tamai asked a group of 23 talented student pilots, all of whom he had trained, to volunteer for the special attack force. All of the pilots raised both of their hands, thereby volunteering to join the operation. Later, Tamai asked Lt Yukio Seki to command the special attack force. Seki is said to have closed his eyes, lowered his head and thought for ten seconds, before saying: "please let me do that." Seki thereby became the 24th kamikaze pilot to be chosen. However, Seki later wrote: "Japan's future is bleak if it is forced to kill one of its best pilots. I am not going on this mission for the Emperor or for the Empire... I am going because I was ordered to."
The names of four sub-units within the Kamikaze Special Attack Force were Unit Shikishima, Unit Yamato, Unit Asahi, and Unit Yamazakura. These names were taken from a patriotic poem (waka or tanka), "Shikishima no Yamato-gokoro wo hito towaba, asahi ni niou yamazakura bana" by the Japanese classical scholar, Motoori Norinaga. The poem reads:
A less literal translation might read: "if someone asks about the spirit of Japan, it is the flowers of mountain cherry blossom that are fragrant in the rising sun"

First kamikaze unit
According to eyewitness accounts, the first Allied ship to be hit by a kamikaze attack was the flagship of the Royal Australian Navy, the heavy cruiser HMAS Australia. The attack appears to have been spontaneous and was carried out by an unknown pilot who was not a member of Onishi's Special Attack Unit. The pilot was most likely an Imperial Japanese Army Air Force aviator from the 6th Flying Brigade, in a Mitsubishi Ki-51 ("Sonia").
By day's end on October 26, 55 kamikaze from the special attack force had also damaged the large escort carriers USS Sangamon, USS Suwannee, USS Santee, and the smaller escorts USS White Plains, USS Kalinin Bay, and USS Kitkun Bay. In total seven carriers had been hit, as well as 40 other ships (five sunk, 23 heavily damaged, and 12 moderately damaged).
HMAS Australia returned to combat at the Battle of Lingayen Gulf in January 1945. However, between January 5 and January 9, the ship was attacked several times by kamikazes and suffered damage which forced it to retire once more. [1] The ship lost about 70 crew members to kamikaze hits. Other Allied ships which survived repeated hits from kamikazes during World War II included the Franklin and another Essex class carrier, USS Intrepid.

Leyte Gulf: the first attacks
Early successes, such as the sinking of the St. Lo were followed by an immediate expansion of the program, and over the next few months over 2,000 planes made such attacks.
When Japan began to be subject to intense strategic bombing by B-29 bombers, the Japanese military attempted to use suicide attacks against this threat. During the northern hemisphere winter of 1944-45, the Imperial Japanese Army Air Force formed the 47th Air Regiment, also known as the Shinten Special Unit (Shinten Seiku Ta) at Narimasu Airfield, Nerima, Tokyo, to defend the Tokyo Metropolitan Area. The unit was equipped with Nakajima Ki-44 Shoki ("Tojo") fighters, which they were to ram USAAF B-29s in their attacks on Japan. However, this proved much less successful and practical since an airplane is a much faster, more maneuverable, and smaller target than a warship. The B-29 also had formidable defensive weaponry, so suicide attacks against the plane demanded considerable piloting skill to be successful. That worked against the very purpose of using expendable pilots and even encouraging capable pilots to bail out before impact was ineffective because vital personnel were often lost when they mistimed when to exit and were killed as a result.
Sub-Lieutenant Nakano, Petty Officer Shihara, PO Goto and PO Taniushi carried out the last kamikaze operation from the Philippines on January 6, 1945, from Mabalacat.
However, kamikaze attacks were being planned at far-flung Japanese bases. On January 8, Onishi formed a second official naval kamikaze unit, in Formosa. On March 11, the U.S. carrier Randolph was hit and moderately damaged at Ulithi Atoll, in the Caroline Islands, by a kamikaze that had flown almost 2,500 miles (4,000 km) from Japan, in a mission called Operation Tan No. 2. On March 20, the submarine USS Devilfish survived a hit from an aircraft, just off Japan.
Purpose-built kamikaze planes, as opposed to converted fighters and dive-bombers, were also being constructed. Ensign Mitsuo Ohta had suggested that piloted glider bombs, carried within range of targets by a mother plane, should be developed. The First Naval Air Technical Bureau (Kugisho), in Yokosuka, refined Ohta's idea. Yokosuka MXY7 Ohka rocket planes, launched from bombers, were first deployed in kamikaze attacks from March 1945. U.S. personnel gave them the derisive nickname "Baka Bombs" (baka is Japanese for "idiot" or "stupid"). A specially-designed propellor plane, the Nakajima Ki-115 Tsurugi, was a simple, easily-built aircraft, intended to use up existing stocks of engines, in a wooden airframe. The undercarriage was non-retractable: it was jettisoned shortly after take-off for a suicide mission and then re-used on other planes. During 1945, the Japanese military began stockpiling hundreds of Tsurugi, other propellor planes, Ohka, and suicide boats, for use against Allied forces expected to invade Japan. Few were ever used.
Main wave of attacks
In early 1945, Commander John Thach, a U.S. Navy air operations officer, who was already famous for developing effective aerial tactics against the Japanese such as the Thach Weave, developed an anti-kamikaze strategy called the "big blue blanket". This plan called for round-the-clock fighter patrols over Allied fleets. However, the U.S. Navy had cut back training of fighter pilots, so there were not enough Navy pilots available to counter the kamikaze threat.
Thach also recommended larger combat air patrols (CAP), further from the carriers than had previously been the case, intensive fighter sweeps over Japanese airfields, the bombing of Japanese runways with delayed action fuses to make repairs more difficult, a line of picket destroyers and destroyer escorts at least 50 miles (80 km) from the main body of the fleet to provide earlier radar interception, and improved coordination between fighter direction officers on carriers.
As the end of the war approached, the Allies did not suffer significantly more damage, despite having far more ships and being attacked in far greater density. Poor training tended to make kamikaze pilots easy targets for experienced Allied pilots, who also flew superior aircraft. Moreover the U.S. Fast Carrier Task Force alone could bring over 1,000 fighter aircraft into play. Allied pilots became adept at destroying enemy aircraft before they struck ships. Allied naval crews had begun to develop techniques to negate kamikaze attacks, such as firing their high-caliber guns into the sea in front of attacking planes flying near sea level, in order to create walls of water which would swamp the attacking planes. Although such tactics could not be used against Okhas and other fast, high angle attacks, these were in turn more vulnerable to anti-aircraft fire. In 1945 large amounts of anti-aircraft shells with radio frequency proximity fuzes became available, these were on average seven times more accurate than regular shells.

Allied defensive tactics
The peak in kamikaze attacks came during the period of April-June 1945, at the Battle of Okinawa. On April 6, 1945, waves of planes made hundreds of attacks in Operation Kikusui ("floating chrysanthemums"). At Okinawa, kamikaze attacks focused at first on Allied destroyers on picket duty, and then on the carriers in the middle of the fleet. Suicide attacks by planes or boats at Okinawa sank or put out of action at least 30 U.S. warships[2] and at least three U.S. merchant ships[3], along with some from other Allied forces. The attacks expended 1,465 planes. Many warships of all classes were damaged, some severely, but no aircraft carriers, battleships or cruisers were sunk by kamikaze at Okinawa. Most of the ships destroyed were destroyers or smaller vessels, especially those on picket duty.[4]
U.S. aircraft carriers, with their wooden flight decks, were more vulnerable to kamikaze hits than the reinforced steel-decked carriers from the British Pacific Fleet (BPF) which operated in the theatre during 1945. The resilience of well-armoured vessels was shown on May 4. Just after 11:30, there was a wave of attacks against the BPF. One Japanese plane made a steep dive from "a great height" at the carrier HMS Formidable and was engaged by AA guns.[5] The kamikaze was hit at close range but crashed into the flight deck, making a massive dent about 10 feet (3 m) long, two feet (0.6 m) wide and two feet deep in the armoured flight deck. A large steel splinter speared down through the hangar deck and the centre boiler-room, where it ruptured a steam line and came to rest in a fuel tank, starting a major fire in the aircraft park. Eight crew members were killed and 47 were wounded. One Corsair and 10 Grumman Avengers were destroyed. However, the fires were gradually brought under control, and the crater in the deck was repaired with concrete and steel plate. By 17:00, Corsairs were able to land. On May 8, Formidable was again damaged by a kamikaze, as was the carrier HMS Victorious and the battleship HMS Howe.
Sometimes twin-engined aircraft were used in planned kamikaze attacks. For example, Mitsubishi Ki-67 Hiryū ("Peggy") medium bombers, based on Formosa, undertook kamikaze attacks on Allied forces off Okinawa.
Rear Admiral Matome Ugaki, the second in command of the Combined Pacific Fleet, directed the last official kamikaze attack, sending some Yokosuka D4Y Suisei "Judy" dive bombers from the 701st Air Group against the Allied fleet at Okinawa on August 15, 1945.
At least one kamikaze attack was made against land forces of the Soviet Red Army, on August 19, 1945, during Operation August Storm.

Final phase
By the end of World War II, the Japanese naval air service had sacrificed 2,525 kamikaze pilots, and the army air force had lost 1,387. According to an official Japanese announcement, the missions sank 81 ships and damaged 195, and according to a Japanese tally, suicide attacks accounted for up to 80 percent of the U.S. losses in the final phase of the war in the Pacific.
According to a U.S. Air Force source:
Approximately 2,800 Kamikaze attackers sunk 34 Navy ships, damaged 368 others, killed 4,900 sailors, and wounded over 4,800. Despite radar detection and cuing, airborne interception and attrition, and massive anti-aircraft barrages, a distressing 14 percent of Kamikazes survived to score a hit on a ship; nearly 8.5 percent of all ships hit by Kamikazes sank. [6]
In a 2004 book, World War II, the historians Wilmott, Cross & Messenger stated that more than 70 U.S. vessels were "sunk or damaged beyond repair" by kamikazes.

Effects
The establishment of kamikaze forces required recruiting men for the task — this proved easier than the commanders had expected. Qualifications were simple: "youth, alertness and zeal. Flight experience was of minimal importance and expertise in landing a luxury." After all, these men were not really going to need to know how to land a plane if all they were meant to do was crash the plane into a carrier. Captain Motoharu Okamura commented that "there were so many volunteers for suicide missions that he referred to them as a swarm of bees, explaining: 'Bees die after they have stung.'"

Recruitment
When you eliminate all thoughts about life and death, you will be able to totally disregard your earthly life. This will also enable you to concentrate your attention on eradicating the enemy with unwavering determination, meanwhile reinforcing your excellence in flight skills. (A paragraph from a kamikaze pilots' manual.)
Tokkōtai pilot training, as described by Kasuga Takeo,

Training
The Japanese were heavily influenced by Shinto beliefs. Shinto involved the worship of kami, or spirits, and its exact origins are unknown. When it was adopted by the entire Japanese nation as the state religion during the Meiji Restoration, emperor worship was stressed. "As time went on, Shinto was increasingly used in the advertising of nationalists' popular sentiments. In 1890, the 'Imperial Rescript on Education' was passed, and students were required to ritually recite its oath to 'offer yourselves courageously to the State' as well as protect the Imperial family." (Referenced Wikipedia article on Shinto). The ultimate offering was to give up one's life. It was an honor to die for one's country – to die for one's emperor. Axell and Kase pointed out: "The fact is that innumerable soldiers, sailors and pilots were determined to die, to become eirei, that is 'guardian spirits' of the country. … Many Japanese felt that to be enshrined at Yasukuni was a special honour because the Emperor twice a year visited the shrine to pay homage. Yasukuni is the only shrine, deifying common men, which the Emperor would visit to pay his respects."
From the earliest age these ideals were implanted in the minds of Japanese youth. To aid with recruiting and support for the Kamikaze, newspapers and books ran advertisements, articles, and stories regarding the suicide bombers. In October 1944 the Nippon Times quoted Lieutenant Sekio Nishina: "The spirit of the Special Attack Corps is the great spirit that runs in the blood of every Japanese…. The crashing action which simultaneously kills the enemy and oneself without fail is called the Special Attack…. Every Japanese is capable of becoming a member of the Special Attack Corps." Publishers also played up the idea that the Kamikaze were enshrined at Yasukuni and ran exaggerated stories of Kamikaze bravery – there were even fairytales for little children that promoted the Kamikaze. A Foreign Office official named Toshikazu Kase said: "It was customary for GHQ [in Tokyo] to make false announcements of victory in utter disregard of facts, and for the elated and complacent public to believe them."
While many stories were falsified, some were true, such as the story of Kiyu Ishikawa who saved a Japanese ship when he crashed his plane into a torpedo that an American submarine had launched. The sergeant major was post-humously promoted to second lieutenant by the emperor and was enshrined at Yasukuni. Stories like these, which showed the kind of praise and honor death produced, encouraged young Japanese to volunteer for the Special Attack Corps and instilled a desire in the youth for the death of a Kamikaze.
Ceremonies were carried out before kamikaze pilots departed on their final mission. They were given the flag of Japan or the Rising sun flag (Japanese naval ensign), enscribed with inspirational and spiritual words, Nambu pistol or katana and drank sake before they took off generally. They put on a headband with the rising sun, and a sennibari, a "belt of a thousand stitches" sown by a thousand women who made one stitch each.
"It's all a lie that they left filled with braveness and joy, crying, 'Long live the emperor!' They were sheep at a slaughterhouse. Everybody was looking down and tottering. Some were unable to stand up and were carried and pushed into the plane by maintenance soldiers."

Cultural background
I cannot predict the outcome of the air battles but you will be making a mistake if you should regard Special Attack operations as normal methods. The right way is to attack the enemy with skill and return to the base with good results. A plane should be utilized over and over again. That's the way to fight a war. The current thinking is skewed. Otherwise you cannot expect to improve air power. There will be no progress if flyers continue to die. (Lieutenant Commander Iwatani, in Taiyo (Ocean) magazine, March 1945.)

Quotations

Captain Motoharu Okamura, commander of the Tateyama Airfield, near Tokyo and the 341st Air Group, may have first proposed these tactics in June 15, 1944, during the first naval battle at the Philippines. See also