Paulsen was one of the first players to challenge the notion that an attack could be constructed out of brilliance. He put forward the idea that any brilliant attack would have failed against correct defence. His ideas were grasped by Wilhelm Steinitz, who declared that attack and defence have equal status, and particularly by Aron Nimzowitsch, who listed Paulsen among his six greatest "purely defensive players". Paul Morphy and Paulsen were early masters of the game and of blindfold chess; they were capable of playing 10 blindfold games at the same time without any major errors. In 1862 Paulsen challenged Adolf Anderssen for the world championship. The eight-game match was a tie and Anderssen remained an unofficial world champion. Paulsen defeated Anderssen in matches in 1876 and 1877.