Colorado Countergambit Accepted

By capturing on f5, White accepts the pawn offered with 2...f5, a gambit that Eric Schiller also lists as the Lean Variation. The capture draws White's e-pawn away from d5, and Black almost always replies 3...d5 at once, building a two-pawn center and preparing to recover the material with the c8 bishop. Recommended practice for White is to let the pawn go with 4. d4 Bxf5. Black then has the extra center pawn, but the kingside has been loosened, and the engine rates White's position as clearly better. On Lichess, however, Black's results are slightly ahead of White's.

Attempts to keep the pawn are less attractive. 4. Bd3 shuts in the d-pawn. The tricky 4. Nh4 sets a trap: the natural 4...e5? runs into 5. Qh5+, and 5...g6? loses to 6. fxg6 Nf6 7. g7+ Nxh5 8. gxh8=Q, so Black has to move the king instead. Rarer third moves for Black are 3...Nf6 and 3...d6, which develop before the recapture.