<p>North Korean industry helped the Japanese during World War II, and now was supplying not only its home country but also Manchuria. The Japanese-built Korean hydroelectric projects, among the world's largest, exported power. The main source for NKA war materiel was Russia. The decision had been made not to provoke that country, and so strategy in Korea had to stop at the Yalu river border with Manchuria.
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<p>There were four major industrial centers on the northeast coast and one on the west, typical strategic targets. Because they were crowded together in complexes, the basic decision was to hit them by areas and not by target systems. For area bombing, incendiaries were the weapon of choice; a backup plan based on the use of demolition bombs and precision bombing tactics also was offered.
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<p>The strategic campaign started on 13 July, when the 22nd and 92nd Groups flew their B-29s against the rail center at Wonsan. The dust had hardly cleared before MacArthur demanded their return to support the Eighth Army. The campaign had opened and closed, temporarily, with a single attack.
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<p>The Joint Chiefs of Staff chafed at the delay. North Korea was contributing to the strength of Russia in the Cold War. Its chemical industry was supplying some of the radioactive elements the USSR was using in its nuclear weapons research. To guarantee the bombing offensive, the JCS authorized two more B-29 groups, with the proviso that they be used only in the strategic campaign.
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<p>The kind of bombing the JCS had in mind was demonstrated in three successive missions flown against the complex of explosives and fertilizer factories at Hungnam. With no guarantee of good weather, the ability to bomb by radar was necessary, and the 19th BG did not have the AN/APQ-13 radar installed. FEAF sent the 22nd and 92nd groups out against Hungnam, an easily discerned target for World War II radar equipment.
