So What was included as the Japanese-edition bonus track on Metallica's 1991 album Metallica.
The song is a cover of a track by the English punk band Anti-Nowhere League. Metallica recorded it as a loose, irreverent addition to the album's otherwise original twelve-song program. On the Japanese edition, So What appeared as track 13 after The Struggle Within.
The standard album sequence contains twelve songs, beginning with Enter Sandman and ending with The Struggle Within. The Japanese bonus track expanded that edition's listed total to thirteen songs and increased its total running time.
So What is easy to confuse with other Metallica covers released around the same period. Am I Evil? and Breadfan appeared on earlier releases and later collections, while Stone Cold Crazy was associated with Garage Inc. The Japanese bonus track on the Black Album itself was So What.