Kamikaze attacks, Japanese for "divine wind", were the general term for Japanese suicide attacks, by aircraft, on U.S. ships. They were a subset of the larger program of tokko suicide weapons and tactics in the air, on land, and sea. Major organized attacks began T in October 1944 and continued to the end of the war.
The word kamikaze (Japanese: 神風) was originally used to refer to major typhoons in the years 1274 and 1281. These typhoons dispersed Mongol armadas on their way to an invasion of Japan. As the typhoons were believed to be gifts from the gods, they were given the name kamikaze, from the words kami for "god", "spirit", and "divinity", and kaze for "wind".
Kamikaze attacks were most important at the Battle of Okinawa in spring 1945; during the three-month battle, 4000 kamikaze sorties sank 38 US ships and damaged 368 more, killing 4,900 sailors in the United States Fifth Fleet. Expecting far more Kamikaze attacks once the main islands of Japan were invaded, the U.S. high command rethought its strategy and used atomic bombs to end the war instead of an invasion.
In 1944, as Allied forces were advancing towards Japan. Japan's military aircraft, such as the A6M Zero, were completely outclassed by Allied aircraft, including the F6F Hellcat and the F4U Corsair. Japan had lost most of its best pilots in air battles against the Allies. Finally, in the Battle of the Philippine Sea, Japan lost a huge number of carrier-based planes, as well as their pilots. One early proposal for suicide tactics came from Captain Eiichiro Jo, naval aide to Emperor Hirohito.  Specific tactics were worked out under Vice Admiral Takajiro Ohnishi.
These problems, as well as shortages of fuel and spare parts, led Japan to develop kamikaze tactics, with planes full of explosives, enough fuel for a one-way trip, and a pilot psychologically prepared to die. The Kamikaze attacks worked because they turned basic "dumb" gravity bombs, as well as the kinetic energy and combustible fuel of an aircraft, into a precision-guided munition.
Young, well-educated Japanese men volunteered to become kamikaze pilots to express their intense desire to protect their country at all costs and to enjoy the glory that such a sacrifice would afford them in the afterlife.
Toward the end of the war the Japanese press encouraged civilians to emulate the kamikaze pilots who willingly gave their lives to stop American naval forces. Civilians were told that the reward for such behavior was enshrinement as a warrior-god and spiritual protection in the afterlife.
Most aircraft used in kamikaze attacks were fighters and dive-bombers. However, purpose-built kamikaze aircraft were also constructed. IJN doctrine teamed Air Fleets, or actual combat aircraft organizations, with Base Air Forces, which were logistical. Fifth Base Air Force, commanded by Vice Admiral Heigo Tominaga and then Vice Admiral Ohnishi, was the Naval aviation organization specifically responsible for the Philippines. First Air Fleet was the combat arm. Under Admiral Kimpei Teraoka, it had moved its headquarters to Clark Field in August and September. Its strength, however, was greatly reduced after the Battle of the Philippine Sea in June, and U.S. air strikes on the Philippines in September. Frustrated pilots had been discussing suicide tactics since 1943. 
After an inspection trip on October 13, Admiral Toyoda, Commander-in-Chief, Combined Fleet replaced Teraoka with Vice Admiral Takijiro Ohnishi and initially made him responsible for the air aspects of the SHO operation. Also on October 13, Rear Admiral Masafuni Arima, had made a suicide dive on the USS Franklin, a carrier bombing Formosa. It was an unauthorized action; Teraoka had told him "When you can show me how to bring the men back from the special attack [called tokko], then I will listen." 
Second Air Fleet and Sixth Base Air Force, under Vice Admiral Fukudome, was responsible for southern Kyushu, the Ryukyus, and Formosa. After the Formosa raids, it moved to the Philippines on October 22. Fukodome still supported conventional techniques as opposed to Ohnishi's focus on suicide attack.
On October 25, Ohnishi, fortified by an interview with the Emperor, offered to accept a subordinate position in a combined organization. Fukudome was senior to Ohnishi so took control of their merged organization, the Southwest Area Fleet Combined Land Based Air Force, but with a significant compromise:  Fukudome would accept the kamikaze principle, although some of the Second Air Fleet units could keep conventional missions. 
Adapting standard aircraft
Fighters were preferred. 
These included the Yokosuka MXY7 Ohka, nicknamed the "baka bomb" (baka is Japanese for "idiot"), and the Nakajima Ki-115 Tsurugi.
The Ohka, effectively a manned cruise missile, was a rocket powered aircraft which was launched from a bomber aircraft. The Tsurugi was an extremely simple aircraft with a wooden fuselage and a reusable undercarriage, designed to use up obsolete engines. In 1945, Japan stockpiled hundreds of planes, Tsurugi, suicide boats, and Ohka for use against the Allied invasion of Japan expected in fall 1945.
First major operation: Philippines
Leyte Gulf was the first place at which the Japanese used large kamikaze forces, starting operations on the 25th. According to Fukudome's operations officer, Ohnishi, who committed seppuku at the end of the war, had planned these operations a month earlier.  These attacks continued well after the main Battle of Leyte, including operations against convoys supporting U.S. land forces. The first significant attack, which damaged the escort carriers USS Santee and USS Suwanee, was not strictly part of any of the four major sea battles, although it was on Taffy 1, between 0740 and 0758, while it was supporting the Action off Samar. Lieutenant Yukio Seki led a flight from Macabalat against Taffy 1, and had radioed the position of Taffy 3. Additional kamikazes attacked Taffy 3 at approximately 1030, sinking the USS St. Lo and damaging the USS Kitkun Bay. 
- Hiroaki Sato, Gyokusai or “Shattering like a Jewel”: Reflection on the Pacific War, The Asia-Pacific Journal: Japan Focus
- G. Miki Hayden, "What Motivated the Kamikazes?" Naval History 2005 19(2): 22-24. Issn: 1042-1920 Fulltext: Ebsco
- David C. Earhart, "All Ready to Die: Kamikazefication and Japan's Wartime Ideology." Critical Asian Studies 2005 37(4): 569-596. Issn: 1467-2715 Fulltext: Ebsco
- Rikihei Inoguchi, Tadashi Nakajima, Roger Pineau, The Divine Wind: Japan's Kamikaze Force in World War II, Naval Institute Press, pp. 25-26
- Edward P. Hoyt (1983), The Kamikazes, Burford Books, ISBN 1580800319, pp. 22-23
- Hoyt, The Kamikazes, pp. 9-12
- Hoyt, The Kamikazes, pp. 70-71
- Interrogation of: Vice Admiral FUKUDOME, Shigeru, IJN, U.S. Strategic Bombing Survey, 9-12 December 1945, INTERROGATION NAV NO. 115/USSBS NO. 503
- Hoyt, The Kamikazes, pp. 80-84
- Hoyt, The Kamikazes, pp. 47-48
- "Interrogation of: Commander YAMAGUCHI, Moriyoshi; from August 1944 to January 1945 Operations Officer on the Staff of Vice Admiral FUKUDOME, CinC Second Air Fleet (FORMOSA), and after 23 October CinC First Combined Base Air Force (LUZON).", U.S. Strategic Bombing Survey, 26 October 1945, INTERROGATION NAV NO. 44/USSBS NO. 193
- William T. Y'Blood (1987), The Little Giants: U.S. Escort Carriers against Japan, U.S. Naval Institute, ISBN 0870212753 pp. 206-219