Blunderer wrote on 10/25/11 at 20:56:54:
yes - but why does this formation create a greater imbalance than symmetry. Its not as if in either case they are on a close circuit with each other.
I'm trying to understand what the 'imbalance' is created by. I suspect it is somethign to do with the interact with the c1 and f8 bishops.....
I think the hypothesis is a general one, that more symmetrical positions tend to be more drawish, or at least tend to be more technical in nature. In symmetrical positions small difference in piece placement, or one tempo, can create an initiative, but not usually one of huge magnitude. Where there is less symmetry there is more instability. Because this is a strategic, long-term idea, it is based on playing the percentages--something is more likely to happen but you don't know exactly what. That's why it's hard to pin down.
Many players want to enhance their winning (and losing) chances in the notorious exchange variation which, as with the Slav, deters some from playing the French; so they choose contrasting piece placements for their own sake in those situations where the choices are relatively equal in merit.
Similarly if your opponent plays a setup with c3 you can play Nc6, and if your opponent plays Nc3 you can play c6.
For the same purpose you can also try to avoid building up (and eventually trading--more drawish) heavy pieces on the e-file, if only you cover all the entry squares carefully.
Finally the ultimate unbalancing strategy in the French exchange is opposite-side castling.