hikaru vs reevecanada

White moved the queen from d1 to f3. The move shields the pawn on f2, which was under direct attack by Black’s queen on g5, and adds a new defender to the e5‑knight’s square. By placing the queen on f3 White also connects the rooks and keeps the king safe while maintaining pressure on Black’s central pieces.

If White had ignored the threat on f2 (e.g., 15.Qd2 or 15.Rd1) Black would capture on f2 with check, winning material and exposing the white king. Qf3 eliminates that immediate danger. Although Black can reply 15…Bxe5, the resulting position leaves Black’s queen on g5 without a safe retreat and the white king remains well‑protected; any continuation for Black is at best equal, whereas other white moves would lead to a clear loss. The engine therefore rates Qf3 as the optimal continuation because it neutralises the most forcing Black threat while preserving all of White’s pieces.

Defend the most vulnerable point first: When an opponent targets a pawn or piece that is undefended (here the f2 pawn), the correct response is to eliminate that danger before pursuing your own plans. This principle keeps the king safe and prevents losing material.