Modern Defense Mongredien Defense Interference in Chess

In the Modern Defense Mongredien Defense, “interference” is a tactical motif where one piece blocks or deflects another defender’s line, so a threat (often on a key file, diagonal, or square) suddenly becomes effective. A defining feature is the Mongredien setup where Black’s pieces aim at central/queenside targets while White tries to exploit the moment a line is overloaded or unprotected.