 After his move to Kinheim for the 2006 Hoofdklasse season, Koolen hit .324/.435/.426 with 27 walks in 42 games.He was 5th in the league in OBP and tied Eugene Kingsale, Tjerk Smeets and Evert-Jan 't Hoen for fifth in walks.He only hit .190/.292/.190 in the Holland Series but Kinheim won the title, breaking the long run by Koolen's old Neptunus mates.