411 REFERENCE · Wikibooks
Chess Opening Theory/1. d4/1...d5/2. c4/2...c6/3. Nf3/3...Nf6/4. Nc3/4...dxc4/5. a4/5...Bf5/6. e3/6...e6/7. Bxc4/7...Bb4/8. O-O/8...Nbd7/9. Qe2/9...Bg6
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Dutch Variation D19 Dutch Variation Euwe Variation
9...Bg6
Black prophylactically retreats the bishop so that /10. e4/ doesn't come with tempo. This allows for Black to win a pawn at the cost of giving White a big initiative.
Theory table
10. e4 O-O 11. Bd3 Bh5 12. e5 Nd5 10. ... Bxc3 11. bxc3 Nxe4 12. Ba3 Qc7 compensation
References
See also