In mid-April 1942 the Japanese military was jarred by a bombing raid over Tokyo, launched from a United States carrier. Believing the planes had launched from the Aleutian Islands, the Japanese planned to attack the Aleutian and Midway Islands simultaneously to wipe out the Pacific Fleet while defending Japan's northern flank. In May 1942 cryptographers cracked the Japanese code and learned of an imminent attack on the Navy base at Dutch Harbor on the east end of Unalaska Island. The bombing lasted from June 2 until June 4, costing 78 American lives and 14 airplanes, but last minute preparations kept the base intact. Heavy fog frustrated commanders on both sides, and williwaws (microbursts at sea level) wreaked havoc with planes and ships. About a week later American commanders realized that some 2,500 enemy troops had landed on the islands of Attu (at left) and Kiska, both west of Unalaska Island. Despite frightful weather, the United States initiated the "Kiska blitz" but withdrew after 11 days. The 11 Americans and 39 Aleuts who were captured on the islands were sent to Japanese prison camps for the duration of the war. Pictorial Histories Publishing Company archives, Stan Cohen author/publisher