Wikipedia
Östgötaderbyt (lit. The Östergötland Derby) is the fixture between the two association football clubs IFK Norrköping and Åtvidabergs FF, it is a local derby in Östergötland, Sweden and a fierce rivalry. The derby is commonly known as Östgötaderbyt, although this is a generic term that could be used for any fixture between two clubs in Östergötland. The rivalry has arisen because the two clubs are the most successful clubs in Östergötland. The two clubs have also played most seasons in the top tier league Allsvenskan of all Östergötland clubs and they are also the two out of just three Östergötland clubs to have won the Swedish football championship, IFK Norrköping with 12 titles and Åtvidabergs FF with 2 titles. The majority of all matches between the two clubs have taken place in Allsvenskan, but fixtures have also taken place in Division 2 and Superettan. Both teams play in Allsvenskan as of the 2015 season.