411 REFERENCE · Wikibooks
Chess Opening Theory/1. e4/1...c6/2. d4/2...d5/3. e5/3...c5/4. c3/4...Nc6/5. Nf3/5...cxd4/6. cxd4
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Caro-Kann - Advance Variation, Botvinnik-Carls
6. cxd4 · Caro-Kann - Botvinnik-Carls Defence
Now Black can safely develop the weak Caro-Kann light-squared bishop bishop to g4, and at the same time threaten to remove the knight defending d4.
Theory table
6... Bg4 6... Bf5 6... a6
References
Caro-Kann