Nxd4 Puzzle (Rated 1500): Deflect — Fork Tactic

Deflection from a fork is a tactical idea in which a valuable defender is lured away from its duty, allowing a second threat to succeed. The strongest version often combines an attacked piece, an overloaded defender, and a forcing check or capture. In this puzzle, Black must recognize that exchanging on the central square changes the defensive geometry and lets the knight exploit a newly weakened king zone. The result is a decisive material gain rather than a mating attack.