“The divine wind: Kamikaze,” were a group of Japanese suicide bombers who crashed their specially made planes directly into Word War II Allied ships, but also many kamikazes were standard aircraft and not specially made. On October 25, 1944, the Empire of Japan employed kamikaze bombers for the first time at the ferocious Battle of Leyte Gulf, the largest naval battle in history, which took place in the Pacific Ocean near the Philippines. Kamikaze strikes against Allied warships continued throughout World War II. Kamikaze pilots would deliberately crash planes filled with explosives directly into enemy warships. It was a desperate policy.
Motoharu Okamura, a kamikaze squadron commander, is noted to have said: “I firmly believe that the only way to swing the war in our favor is to resort to crash-dive attacks with our planes. There is no other way. Provide me with 300 planes and I will turn the tide of war.”
Most Kamikaze pilots were university students motivated by obligation and gratitude to family and country. They prepared for their missions by holding ceremonies where they wrote farewell poems to their families, receiving honor and respect from the country's highest officials. Marines suffered a huge number of casualties on land at Iwo Jima; 6,000+ dead, 19,000+ wounded.
With only 215 of the Japanese garrison of 22,000 surrendering and the maniacal Kamikaze attacks at Okinawa that were responsible for 100,000 Japanese casualties, some historians believe that these two battles convinced Truman that if he wasn’t already, that using Atomic Weapons on Japan was the only way to end the war without US losses that would make Iwo and Okinawa look like a practice scrimmage. The Japanese senior military told the public, “100 million dead before surrender.”
There are higher estimates of both Kamikazes killed and damage caused, but even if you take the most favorable (from a Japanese perspective), only about 14–20% of attacks were successful, in that they scored a hit. By late in the war, Japan had lost nearly all their experienced pilots, which was another reason why some saw Kamikaze as their only remaining option. Japanese pilot crews in 1945 were nothing like that of those that had attacked Pearl Harbor. By 1944–45, these pilots were trained on wooden crates with sticks and wooden pedals. They got virtually zero actual flight training. Some sources say they weren’t even taught to land, although that is hard to believe, as there are records of Kamikazes returning after being unable to find targets due to weather or poor navigation.
However, strategically, it was not sustainable as it did not really make a significant contribution to the Japanese war effort, and further depleted the Empire of fuel and planes that could have been used to defend the home islands, had the two nuclear bombs had not sealed the deal.
According to https://history.howstuffworks.com, thousands of kamikaze sorties were launched in the final months of the war, and more than 3,000 Japanese pilots were killed. Those attacks resulted in the sinking of some 47 ships, killing more than 7,000 U.S., Australian and British sailors. Doesn’t that sound deadly and horrifying.
But in fact, they weren’t.
The statistics says that 27 percent of the attacks in [the battle of] the Philippines resulted in either a hit or a near miss that caused damage to the ship... In the battle of Okinawa, when most of the kamikaze pilots were going in, I think it was like 13 percent," Bill Gordon, who has been collecting data and stories on kamikaze on his site, "KamikazeImages," since the early 2000’s, says from a town near Nagoya, Japan. "I guess it's what you compare it to. The reason they were making the attacks was that the conventional attacks were not effective. In the Philippines, they originally thought they were doing great. But 13 percent is pretty low.
That means 87 percent were shot down, some well before they reached any ship, by American fighters. "Most people look at it and say they already lost the war by the time the kamikaze attacks started, so regardless of how effective they were, they were going to lose. If the percentages were higher, it really doesn't matter."
Japanese suicide missions in World War II were not only limited to dive-bombing, but also midget submarines (kōhyōteki in Japanese), manned torpedoes, (kaiten), manned rocket-powered gliders (ōka) and motorboats carrying depth-charges (shin'yō) all were used at various stages of the war.
Therefore, to conclude the effectiveness of kamikaze depends on how you look at and compare your data. Numbers alone can be seen as terrifying and disastrous, but when looked upon from a success rate point of view, they weren’t that effective to swing the war in Japan’s favor.