Whirlwind - Barrett Tillman [123]
In the crucial realm of radar, Japan got a jump on the world—and almost immediately lost its lead. The efficient Yagi-Uda antenna had been invented in 1926, the product of two researchers at Tohoku Imperial University. Professor Hidetsugu Yagi published the first English reference two years later, citing his nation’s work in shortwave research. But such was military secrecy and interservice rivalry that even late in the war few Japanese knew the origin of the device that appeared on downed Allied aircraft.
The Allies rated Japanese radar as “very poor,” and fighter direction remained rudimentary. While land-based radar could detect inbound formations perhaps 200 miles out, the data included neither altitude nor composition. Consequently, picket boats were kept 300 miles at sea to radio visual sightings—of marginal use in cloudy weather. However, what radar systems did exist were easily jammed by American radio countermeasures—aircraft dropping aluminum foil that clogged enemy screens.
Furthermore, the Japanese army and navy established separate warning systems, and seldom exchanged information. Even when unit-level pooling was attempted, navy officers generally refused orders from army officers.
Civilian observers were spread throughout Japan to report enemy aircraft, but predictably there was no unity. The army and navy established their own observer corps, and neither worked with the other.
Japanese navy doctrine contained an internal contradiction for air defense. A 1944 manual asserted, “In order to overcome the disadvantages imposed on fighter plane units when the enemy raids a friendly base—that is, getting fighter planes airborne on equal terms with the enemy airplanes—full use must be made of radar and other lookout methods. . . . These must be employed in the most effective manner.” But as noted, use of radar remained rudimentary.
Some pilots dismissed the state of their nation’s electronics. “Why do we need radar? Men’s eyes see perfectly well.”
Excluding mobile radar sets, at least sixty-four early-warning sites were built in the homeland and offshore islands: thirty-seven navy and twenty-seven army. But the rare assets often were squandered by duplicating effort: at four sites on Kyushu and seven on Honshu, army and navy radars were located almost side by side. The southern approaches to Kyushu and Shikoku were covered by some twenty installations but only two permanent radars are known on all of Shikoku.
Though the huge majority of Japanese radars provided early warning, some sets directed AA guns and searchlights. But apparently there was little integration of the two: some B-29 crews returned with harrowing tales of ten to fifteen minutes in a searchlight’s probing beam with minimal or no flak damage.
Apart from inadequate radar, some of Japan’s technical focus was badly misdirected. From 1940 onward, the military devoted over five years to a “death ray” intended to cause paralysis or death by very short-wave radio waves focused in a high-power beam. The nonportable unit was envisioned for antiaircraft use, but the only model tested had a range much less than firearms.
Tactically, the lack of army-navy cooperation hampered the already limited potential of Japan’s interceptors. With unit commanders conducting their own localized battles, there was little opportunity to concentrate large numbers of fighters against a bomber formation as the Luftwaffe repeatedly achieved.
Overall, Japanese fighters were spectacularly ineffective against B-29s. From more than 31,300 Superfortress sorties over the homeland, only seventy-four were known lost wholly to interceptors and perhaps twenty more in concert with flak guns. Japanese pilots logged their best performances in January and April 1945, each with thirteen bombers downed. But during fifteen months of combat, losses to interceptors amounted to merely 0.24 percent of effective B-29 sorties.
The Strategic Bombing Survey concluded, “The Japanese fighter defense system was no more than fair on paper and distinctly poor