Throughout his career, Nikolay has been interested in the observation that many times opening trends and popularity are influenced as much by "fashion" as by
theory. Openings may drop out of favor, yet still be sound.

In these cases, these unusual openings can provide an advantage to the player who springs the surprise. Because of this, he has championed the rediscovery and revival of opening lines that have been forgotten by chess theory, but which remain fundamentally sound.

As the Danish Grandmaster Bent Larsen wrote (from the tournament book for the Second Piatrigorsky Cup):

Chess fans often ask about the way a master prepares for a tournament or important game. In my case the answer is that I do very little special preparation for a given occasion. I do a good deal of opening analysis all the time, and then, sometimes years later, I get the opportunity to use one of my surprise variations. Most of all I like "bad" lines, that is those considered bad, in my opinion unjustly, by "theory". The reason for the last quotation marks is that most so-called theory is only a collection of examples from master practice.