In the Classical Variation with 5.Nf3 0-0 6.Be2 Black reacts against the mighty white centre with the central counter 6...e5. Since White cannot win a pawn in the Exchange Variation 7.dxe5 dxe5 8.Qxd8 Rxd8 with 9.Nxe5 on account of 9...Nxe4, this is not particularly popular. It is only played occasionally in conjunction with 9.Bg5 or 9.Nd5.
In the Classical Main Line White closes the centre after 7.0-0 Nc6 with 8.d5, and after 8...Ne7 he can seize the initiative on the queenside with 9.b4 or with 9.Nd2 or 9.Ne1 he can first redeploy his king’s knight.
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