Knights protecting each other generally lack mobility. How can you render one of your opponent's knights ineffective? How can you avoid being stuck with one yourself and keep your knights flexible? Let's ride!
Retreating the knight back to its initial square! When considering the position that has arisen now, you will soon note that the knight on e4 is in a precarious position. White threatens to follow up with Ne5. He will also try to build a strong pawn center with e2-e4, after which the mobility of Black's minor pieces will be considerably restricted. Besides these concrete ideas, Dvoretsky's concept of superfluous pieces may have crossed Nielsen's mind. After all, three black pieces are aiming for the same square ( e4). By avoiding exchanges White renders at least one of these redundant.
Consistent strategy: White still intends to play Ne5 followed by f2 -f3 and e2-e4, but again does not want to allow an exchange of one minor piece.
Black has managed to exchange one pair of knights, but in the meantime White has regrouped and played f2 -f3 , which results in the immediate threat of e2-e4. Black now went wrong with . . .
Again we see two knights defending each other, tempting White to go for the ambitious and audacious . . .
Keeping all the minor pieces on the board. If White succeeds in driving the black pieces back from e4, his opponent will struggle with his pieces in a passive position.