Does King's Gambit Declined: Falkbeer Countergambit, Nimzowitsch-Marshall Countergambit work for Black at All Ratings?
At All Ratings, King's Gambit Declined: Falkbeer Countergambit, Nimzowitsch-Marshall Countergambit keeps Black's wins running +17.4% ahead of its losses at worst, 90% confident, from 97K Lichess games. This gambit is effective. Win rate, draw rate and loss rate come from games played December 2023 to November 2025.