“Aleutian Operations” propaganda postcard, c. 1942. Kiska, one of the two Alaskan territorial islands occupied by the Imperial Japanese Army, was inhabited only by a small squad US Navy weather station. Eight officers and sailors were captured and sent to Japan as POWs. Attu was inhabited by a small population of native Aleuts.

See also:
USS Saratoga torpedoed, propaganda postcard, 1942.
Sinking the HMS Prince of Wales and HMS Repulse propaganda postcard, 1941.
“Patriotic March” (“Aikoku koshinkyoku”) propaganda postcard, c. 1942.

“In the only two invasions of the United States during the war, a small Japanese force occupied the islands of Attu and Kiska [in the Alaska Territory of the United State] beginning June 3, 1942. The remoteness of the islands and the challenges of weather and terrain delayed for nearly a year a larger U.S.-Canadian force sent to eject them.

“The islands’ strategic value was their ability to control Pacific transportation routes, which is why U.S. General Billy Mitchell stated to the U.S. Congress in 1935, ‘I believe that in the future, whoever holds Alaska will hold the world. I think it is the most important strategic place in the world.’

“The Japanese reasoned that control of the Aleutians would prevent a possible U.S. attack across the Northern Pacific. Similarly, the U.S. feared that the islands would be used as bases from which to carry out a full-scale aerial attack on U.S. West Coast cities like Anchorage, Seattle, Portland, or Los Angeles.”

– Wikipedia