From listening to first hand accounts by family and friends who had witnessed the attack, as well as my personal visits to the Arizona Memorial (including one with K), and as a long time resident of Hawaii, it is an event that has long been of interest to me.
The attack was devastating to the U.S. and would have secured Japan's dominating position in Asia (the so-called "Greater East Asia Co-prosperity Sphere") for a long time had the American aircraft carriers not been at sea at the time.
As President Roosevelt said, it was a day that would live in infamy. But how many people realize that Japan mounted a second raid on Pearl Harbor? I sure didn't, until doing some research on aircraft a few years ago.
Hitting America's aircraft carriers was an important part of the plan to keep the U.S. at bay. The first raid, while a victory for Japan, did not accomplish that. The point of going to war with America was not to try to conquer her. Rather, it was to consolidate Japan's conquests in Asia by crippling the American fleet. Admiral Yamamoto correctly concluded that the attack had only bought about six months time for Japan. If they could not defeat the American navy in that time, they would lose.
Another raid was planned just three months after the initial attack. The idea was to hit the carriers while in port and to disrupt the repairs of battleships that had been damaged in the December attack. This time, a large naval fleet would not be practicable as the element of surprise was lost. Instead, two giant flying boats - the most advanced in the world at the time - would make a daring attempt to attack Pearl Harbor at night.
The airplanes were designated H8K1 and called "Emily" by the allies. Built by Kawanishi, they were huge, with a wing span of 38 meters (124 feet), and a gross take off weight of 32,500 kilograms (71,650 lbs). They were powered by four 1,850 horsepower engines which gave them a top speed of 296 mph. With a crew of ten and defended by ten machine guns and ten 20mm cannons (allied pilots later called it "the flying porcupine") it could fly missions of as long as 24 hours duration. As an anti-submarine plane it carried two torpedoes; as a bomber, eight 550 pound bombs. [A flying boat, by the way, can takeoff and land only on water. Wheels are attached by a ground crew to move it into and out of the water. An airplane that can takeoff and land on either water or a runway is called an "amphibian".]
The two planes used in the raid were based at Wotje in the Marshall Islands, some 2,000 miles from Honolulu. Fully loaded, they could not make the round trip without refueling, so it was arranged to have two submarines at a rendezvous point to refuel the planes at sea.
On March 4, 1942, the planes took off for a night bombing raid on Pearl Harbor. They flew to the French Frigate Shoals in the north western part of the Hawaiian Island chain, where they were refueled by the submarines I-17 and I-19, which had been modified with special tanks for carrying aviation fuel. Seven hours later, the planes approached Oahu.
Meanwhile, in Hawaii, the Americans were of course on high alert ever since the December attack. The women of WARD - Women's Air Raid Defense - were operating radars on Oahu and new stations on Kauai, Mt. Haleakala on Maui, and Hawaii. By March, they had been on the job twelve weeks. In the early hours of March 5th, they had their skills put to the test by the approaching Japanese flying boats. Kaui radar first picked up the flying boats about twenty miles off the coast, headed toward Oahu. The alert went out. Fighter planes were scrambled, searchlights turned on, and anti-aircraft guns manned. But it was a moonless, rainy night and even with vectors from the WARD radar operators, the fighter planes had no success in finding the flying boats.
Due to the cloud cover, the Japanese planes also could not find their targets and had to drop their bombs blind, some of which hit inland from the harbor and two at the harbor entrance. No ships were damaged. The flying boats returned to their base.
Yet another attempt was made a few months later, but was cut short as American ships were patrolling the rendezvous point so the planes could not be refueled and had to return to Wotje.
In June, Admiral Yamamoto attempted to lure U.S. carriers into a trap at Midway, but the plan backfired and planes from the American carriers sank four Japanese carriers and a cruiser. It was a pivotal defeat for Japan. Without those carriers, the Japanese plans to attack Samoa and Fiji, and to invade Hawaii had to be scrapped. While not decisive in and of itself, the battle for Midway marked the beginning of the end for Japan in WWII.
One wonders what may have happened if the weather over Oahu on the night of March 4th to 5th, 1942 had been better. Would the fighter planes directed by WARD have downed the bombers, or would the Japanese planes have found their targets and done sufficient damage to change the outcome of the battle of Midway? The outcome of historic battles sometimes do hinge on such seemingly small points. As Benjamin Franklin wrote, "For the want of a nail, the shoe was lost; for the want of a shoe the horse was lost; and for the want of a horse the rider was lost..."
167 of the Kawanishi HK8s were built during the war. Some conducted (unsuccessful) raids on the Australian mainland. During one of those raids, a lone Emily showed just how tough the plane was by surviving continuous attacks by P-39 Airacobras until the fighter planes ran out of ammunition. Most saw duty as reconnaissance aircraft and some in an anti-submarine role. A transport version was also built, the H8K2-L Seiku (clear sky) which could carry over 60 troops.
After the war, the Americans took one back to the USA for testing, which as it happened was never carried out, and the plane was put into storage. That plane became the sole surviving "Emily", and in 1979 it was returned to Japan where it was finally completely restored as a static display at the Musuem of Maritime Science in Tokyo. K and I visited there in 2003. I marvelled at the plane, not only as a pilot and someone who likes the lines of propeller driven airplanes, but also because my father was an aeronautical engineer during WWII and did a lot of work on Consolidated flying boats such as the PBY Catalina and the four-enginned PB2Y Coronado.
Not many flying boats are manufactured these days, as runways have been built most everywhere in the world. They are still useful for rescue at sea however, and the largest flying boat now in production in the world is actually one with a design layout similar that of the Emily and built by the same company (now ShinMaywa Industries). It's the US-1A, a highly advanced design and the only amphibious plane capable of handling the rough seas around Japan. It would take too long to explain here, but its sea worthiness is largely due to its STOL capability. So the "Emily" lives on in a way, but now with life-saving mission.
The H8K2 that we visited has since been moved to Kanoya Naval Air Station in Kagoshima Prefecture in south-western Japan where many of the type had originally been based. I feel lucky to have been able to see it in person. A beautiful aircraft, the Emily was an aviation achievement that also played an interesting part in the history of the war for control of the Pacific Ocean and her islands.