The album was privately sold through auction house Paddle8, and bosses at the firm announced on Tuesday (24Nov15) an American fan won the bidding war, which started six months ago.

Potential buyers were vetted by Paddle8 officials and representatives for the Wu-Tang Clan, and in the weeks leading up to the official sale contracts were drawn up and legal protections for the album were devised to keep the value of the project linked to its rarity.

The 31-track album was recorded in secret over a six-year period, and the regulations on the music are so tight that a copyright clause prevents the new owner from releasing the music publicly for 88 years.

The sole copy is encased in an engraved silver and nickel box, and comes with a 174-page manuscript containing lyrics, credits and anecdotes on the production of each song.