411 REFERENCE · Wikibooks
Chess Opening Theory/1. e4/1...c6/2. d4/2...d5/3. f3/3...dxe4/4. fxe4/4...e5/5. Nf3/5...Bg4/6. Bc4/6...Nd7/7. c3
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Caro–Kann Defence: Fantasy Variation Tartakower VariationMaróczy Variation
7 .c3 · Fantasy Variation
c3 creates a different threat, that of Qb3, with the queen adding to the pressure on f7 as well as targeting b7. Black cannot play passively, and a move like 7...Nf6 leaves Black in a world of trouble after 8. Qb6.
Black can respond with 8...b5, either chasing the bishop from the diagonal, or blocking the queen from b6. This comes at the cost of queenside weaknesses that White can later target with moves such as a4.
8...Bh5 also holds, perhaps with a later Qc7 and O-O-O, where Black is happy to give up the f7 pawn for a solid position or good counterplay.
8...Bd6 is another playable tactical line, that can give up the b and c pawns, but provides Black with sufficient compensation.
Theory table
7...Bh5 7...Bd6 7...b5
References