Hello,

why is 9... o-o a bad move ?!?   ...TIMING...

1.   With 9...o-o you say goodbye to the "aggressive compensation" on kingside, which will black go for via 9...d6 10. Nd2 e5 11.f4 (f.e.) ef: with g5 and o-o-o in mind.

2.   With your 9...o-o and lets say 10.Nd2 d6 11.f4 you can "feel" what makes the difference! 11...Nd7 12.Qg4 Qe7 13.Rae1. Here you understand what I mean with "aggressive Compensation"...Black is here waiting for a KO....

3.   In this kind of position it is better to wait as long as possible to show your opponent on which side your king will be and to use this TIME for fastest possible counterplay. As you can learn from 1. and 2. Black preferres "fastest developing" instead of "wasting important time" for castling. In our example white will fear that you can attack with pawn g5 etc and castling long...after 9...0-O white would feel very happy because he can pressure Black without any compensation for Black.

By the way: Nd2/f4 is the only way for white to get an advantage...d6/e5/ef/g5...will give you an interesting fight.

Best greetings,

SutterCane

Hi All,

I played the black side of this in a side game.  

1.e4 b6
2.d4 Bb7
3.Nc3 e6
4. Nf3 Bb4
5.Bd3 Nf6
6.Bg5 h6
7.Bxf6 Bxc3+
8.bxc3 Qxf6
9.0-0 0-0

I looked this line up when I got home in the Soltis and Bauer books on 1...b6 and discovered that the text move is 9...d6.  Neither book gives any commentary on 9... 0-0.  

Can someone explain why (stategically and tactically) the text move is better? 

I just want to know why 9...0-0 is bad.