IMRosen vs hikaru

Black to move captured the white rook on d1 with the queen (Qxd1#). The capture removes the last defender of the white king and simultaneously delivers check along the d‑file. Because the white king on b1 has no escape squares (a1 is blocked by its own pawn, a2 is under black threat, and the queen controls c2 and d2), the move ends the game by checkmate.

The engine lists Qxd1# as the only legal move that wins, confirming that any other continuation would either allow the white queen to escape or give White a chance to continue fighting. By taking on d1, Black eliminates White's last active piece, exploits the undefended white king, and converts the material advantage into a forced mate. No alternative move can achieve the same immediate result; any non‑capturing move would leave the white rook on d1 protecting the king and would prolong the game unnecessarily.

Finish with a forced checkmate when the opponent's king is exposed. Once you spot a mating net—especially when the opponent's defending pieces are overloaded or undefended—execute the decisive capture or sacrifice without hesitation. This converts a winning material advantage into an immediate win.