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
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Dutch Variation D18-D19 Dutch Variation Euwe Variation
8...Nbd7
White chooses to develop their knight instead of castling. This move prevents White's knight from jumping to e5 and chasing away the bishop.
White does still have the option of /9. Nh4/, transposing into the Bled attack and claiming the bishop pair.
More common, however, is /9. Qe2/, preparing e4 and going into the main line.
Theory table
9. Qe2 O-O 10. e4 Bg6 11. Bd3 Bh5 12. e5 Nd5 + 9. Nh4 Bg6 10. Nxg6 hxg6 11. h3 O-O
References
See also