Perhaps we have differing definitions of the word. North Korea is not an autarky, as best I see it, i.e. a "...policy of national self-sufficiency and nonreliance on imports or economic aid...."
Most of North Korea's imports are from China, estimated at about 2.5 billion denominated in USD. For a tiny economy as estimated by CIA Fact Book and others, they are no autark but rather reliant on others. Food aid is a part of this.
A quick search brings up:
While complete autarky (total economic self-sufficiency) is virtually impossible today, North Korea is the closest modern example, driven by its Juche ideology, but even it trades heavily with China. Historically, regimes like Nazi Germany, the Soviet Union, and Francoist Spain pursued autarkic policies to limit trade and prepare for conflict, though they never achieved perfect isolation, while countries like Bhutan have limited outside economic ties.