Hartlaub Gambit Declined

Declining the Hartlaub Gambit with 5. d5 leaves the f5 pawn alone and advances in the center. This blunts the b7 bishop's diagonal and gains space instead of grabbing material. Black usually captures with 5...fxe4. The main alternatives are 5...Nf6 and the pin 5...Bb4, and both add pressure against e4. Engines rate the position as roughly balanced. The line is rarely seen, and in the small sample of games decisive results are split evenly.