The Main Line, 5.cxb5 a6 is a variation of the Blumenfeld Countergambit, catalogued as ECO E10. The line runs 1. d4 Nf6 2. c4 e6 3. Nf3 c5 4. d5 b5 5. cxb5 a6, reaching the position shown below after 10 half-moves.
White holds the centre with pawns on d5, and two pawn captures are available, so the structure is still fluid. Development is level at one minor pieces each, and White is up a pawn of material. It is White to move after five moves. White has doubled pawns on the b-file; Black’s a-file pawn is isolated.
On the Blumenfeld Countergambit generally: ECO E10. A chess opening with 3 known variations.
You can play through this variation move by move in your browser — Learn mode walks the line with an explanation at each step, and Drill mode replays it from memory so you find out whether you actually know it. No account is required.
See all 5 Blumenfeld Countergambit variations →
The Main Line, 5.cxb5 a6 goes 1. d4 Nf6 2. c4 e6 3. Nf3 c5 4. d5 b5 5. cxb5 a6. It is a variation of the Blumenfeld Countergambit and is catalogued as ECO E10.
The Main Line, 5.cxb5 a6 is ECO E10. ECO codes group openings by their move order, so nearby codes cover closely related lines of the Blumenfeld Countergambit.
Stockfish evaluates the position after 1. d4 Nf6 2. c4 e6 3. Nf3 c5 4. d5 b5 5. cxb5 a6 at +0.72 at depth 18, which is a small but real edge for White. Engine evaluation is only a starting point — at club level the practical value of a line is mostly about whether you know its plans better than your opponent does.
White holds the centre with pawns on d5, and two pawn captures are available, so the structure is still fluid. Development is level at one minor pieces each, and White is up a pawn of material. It is White to move. White has doubled pawns on the b-file; Black’s a-file pawn is isolated.