The Navy knew of the Japanese plans for the Aleutians.
The string of islands known as the Aleutians curves like a samurai sword, south and then west from Alaska 1,100 miles into the North Pacific—marking the boundary between the North Pacific and the Bering Sea. Adak, Kiska and Attu, the islands at the point of the sword lie perilously close to Japan. Peaks of a submerged mountain range, the Aleutian Islands traverse the coldest, most turbulent portion of the North Pacific. Thick fog shrouds the treeless islands all but constantly, and “williwaws”—gale force winds up to 80 miles an hour–come and go frequently and unpredictably.
Strategic Aleutians and Japanese Plans
Isolated, inhospitable in the extreme, the Aleutians don’t count for much. But they are, indisputably, American soil. And, if the tip of the sword lies close to Japan, its handle rests at Cook Inlet.
By 1942 the strategic importance of Alaska and its long Aleutian tail had caught the eyes of naval strategists in both Tokyo and Washington. Indeed, the soldiers of the Corps of Engineers found themselves in the North Country in the first place because the Army needed to defend Alaska and its tail.
Now the Japanese dispatched two naval forces to assault the Aleutians. First, a carrier group centered on the brand new carrier Junyo and the somewhat older Ryujo would attack Dutch Harbor. Two heavy cruisers, three destroyers and an oiler surrounding them, they steamed through the night of June 2nd in cold rain and icy fog, hiding from American spotter planes at the edge of a storm–less than 170 miles from their target.
Second, three cruisers, nine destroyers, three transports, and a screen of submarines steamed somewhere west of the Carrier Group, carrying the 2,500 soldiers who proposed to occupy Adak, Kiska and Attu.
The success of the Japanese plans at Midway and in the Aleutians ultimately depended on surprising the Americans, but that wouldn’t happen. On May 15 a team of crypto analysts at Pearl Harbor had broken the Japanese naval code and American intelligence knew at least the outline of the Japanese plan. The American Navy wouldn’t fall blindly into Yamamoto’s ambush at Midway, and American commanders had a little bit of time to organize a defense in the Aleutians.
Admiral Nimitz, overall naval commander in the Pacific, convinced that the decisive action would be at Midway, committed most of his resources there. To defend the Aleutians, he dispatched Rear Admiral Robert Theobald north with a token force of nine ships and instructions that amounted to ‘do your best with what you can scare up’. American folklore offers a hoary bit of advice about the wisdom of bringing a knife to a gunfight that is applicable to Theobald’s mission. The Japanese were bringing carriers to the fight; Theobald was not.