Good opening or bad opening?
Are you white or black and what is the move order?
1. d4 d5 2. Nc3? c5 Normally if White is going to delay c4 he will play Nf3. If he is playing Nc3, looking for a Veresov, perhaps, e4 and Bf4 quickly suggest themselves. Although c5 is an attempt to penalize the unorthodox Nc3 what I see is White gaining tempo, leading development and Black getting "airy".
BTW shouldn't this be in the opening forum?
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