hikaru vs only_strong_moves

Hikaru followed the Colle System plan: he placed his dark‑squared bishop on **4.Bd3**, his knight on **5.Nbd2**, and kept the light‑squared bishop on the c1‑h6 diagonal. This development gave him a flexible pawn structure and the ability to play the central break **6.e4** (a pawn thrust that challenges Black’s center). By keeping both bishops on the board, he retained the bishop pair (a long‑term advantage) and ensured his pieces were ready for the upcoming attack.

After the exchange on **13.Nf5** and **14.Bxf5**, Hikaru kept the bishop pair while Black’s pawn on e4 limited his own pieces. He then castled with **15.O-O**, bringing his king to safety and connecting the rooks. The move **16.Bh3** placed the dark‑squared bishop on a safe diagonal and kept an eye on Black’s kingside. By playing **19.Rfd1**, he aligned his rook with Black’s rook on the d‑file, creating pressure on the d‑pawn and the bishop on c5. Finally, the pawn push **20.b4** attacked the bishop, gained space on the queenside, and forced Black to resign. This sequence demonstrates the principle of using open files (the d‑file) and pawn advances to generate threats (space advantage) that the opponent cannot meet.