fabianocaruana vs Sina-Movahed

White played 20.b3, pushing the pawn from b2 to b3. The move does not address Black's immediate threats – the pawn on a3 still eyes the b2‑square (now empty) and Black's knight on f6 continues to attack the pawn on e4. Moreover, White leaves the black bishop on e6 untouched, missing a tactical shot that could win material. After 20.b3 the position remains tactically volatile, with White’s pieces (the knights on c5 and bishops on f4/f3) undeveloped for an attack and the pawn structure unchanged except for the newly created b3 pawn, which is also a new target for Black.

The engine’s 20.Nxe6! exploits the hanging bishop on e6. By capturing with the c5‑knight, White wins a piece (or at least forces an exchange of equal value) and eliminates a key defender of Black’s king side. After 20.Nxe6 fxe6, White retains the bishop pair and opens lines against Black’s king, while Black’s pawn structure is further compromised. In contrast, 20.b3 merely creates a pawn move that does not improve piece activity, leaves the bishop on e6 alive, and gives Black the free continuation 20...Nb4, increasing pressure on the weak b2‑square and the e4‑pawn. The engine’s move directly converts a tactical opportunity into a material gain, whereas the player's move squanders it.

Always seize the most forcing tactical opportunity. When an opponent’s piece is unprotected (here the bishop on e6), prioritize the capture or exchange over quiet pawn moves. Ignoring a hanging piece can cost you a clear material advantage.