So What appeared as the bonus track on the Japanese edition of Metallica's The Black Album. It was placed after the 12 songs on the standard album sequence.
The track is a cover of a song by the English punk band Anti-Nowhere League. Its inclusion gave the Japanese edition a 13th song, while the standard international sequence ended with The Struggle Within.
This regional variation is why album listings can differ in track count. So What is not one of the 12 standard Black Album compositions, and it should not be confused with Metallica covers such as Am I Evil?, Stone Cold Crazy, or Breadfan, which appeared on other releases or in other contexts.