Position of the day-19.9

D'oh . . .

I'm blind.

Ok, I stand by my contention that the tactical threats are real and winning. However Bxc3 is not the only move that deals with those threats. 

Both threats rely on the ability for a piece to capture on d5. Therefore, e6! 

*sigh* this is why i'm not a better player OTB . .. 

Well we have alot of answers here.  Whats the verdict Phillip? lol/

BTW, e5 fails for tacitcal reasons as well. 

eg: 1. ... e5?! 2. Bg5 and now what? 

if 2. ... Qxg5 3. Qxd5 and the queen attacks the rook!
if 2. ... Bf6 3. Qxd5 Qxd5 4. Nxd5 Bxg5 5. Nc7+! 
if 2. ... Nf6 3. Bb5+ Bd7 4. Bxf6 Bxf6 5. Nxd5

Bg5?  can't be right.  If Qxg5 then Qxd5..Rb8.  Then what?  If Bb5+  Then just Rxb5 Nxb5 and Black has 2 pieces for a rook and a pawn.  Then black plays Ne7 kicking the queen and black is just fine.  After Qxd5 black could even play Bh6 and the rook is not capturable as Qd2 is mate.

Scratch the Bh6 idea.  That doesn't work because of Bb5+

Sam,

your definition of space is correct. a control of a square by a pawn, offering the opportunity to place a piece on the controlled square, is stronger than controlling the square with a piece. not to be too general, other effects of controlling a certain square with a pawn should be taken into consideration, for example if moving a pawn to control a square decreases the quality of a certain piece of ours, for example, blocking a bishop (regardless of the given position, only generally speaking).

plus, space controlled by a pawn cannot be saken away regardless of how many pieces of the opponent try to contest it, because by occupying it he loses material. not so when the square was controlled by a piece.

but lets just clear out who has the space advantage in the given position.

white's controlled squares in black's camp:

g5- by a piece. b5- by two pieces.

black's controlled squares in white's camp:

d4,c4-by pawn, although contested by pieces, because it's a pawn vs pieces, the side who contests a square with a pawn controls it. note that both are central, one (d4) is a super central, the other (c4) is an extended center. plus, by contesting the e4 square with the g7 bishop, black also takes away whites control of a central square in his own camp. though inferior to controlin a square in the opponent's camp, taking a way control by contest of that square also should be taken into account.

such is also the case with the g4 square.

so, regarding only space, by counting the number of controlled squares (and their weight- central or not) by each side in their opponent's camp, it's easy to see black has the space avantage.

so already,  we can say that one of the requirements of black's position would be to increase his space advantage.

just reminding you, space is the first stage of positional evaluation, but we first need to decide whether our position as black is safe enough to play a positional move here, and not to try and respond to threats by white.

of course, after we finish looking for opponent's threats and we indeed see a real threat, we still do a positional evaluation, to try and see if we can find a plan and a move that not only respond to the threat, but also answer the strategic requirements of our position.

Thanks Phillip.  Its reassuring to know that I learned something from your lesson yesterday.

1. .. e5?! 2. Bg5 Qxg5 3. Qxd5 

a) ... Bb5+ 4. Nxb5 and Nd6+  is, I believe, fatal
b) ... Bb7 4. Qxb7 Rd8 5. Rd1 has to be good for white. His pawn advantage on the queen side will win in the end.

I see no other moves. 1. .. e5 loses by force as far as I can see. 

Ok, so to be more systematic about it:

Space: Black advantage as described above
Development:

• Queen side rooks are roughly equal, though black has slightly more potential as the rook can immediately move to b8 and be considered developed. -- slightly in favor of black
• Knights, white is developed black is not. -- strongly in favor of white
• Light square bishops, black has potential to develop but is not developed, white has less potential to develop but is not developed. -- slightly in favor of black
• Dark square bishops  both are developed but white's controls more squares in black's camp they both control the same number of central squares. -- slightly in favor of white
• King-side rooks: neither developed and equal potential. -- no advantage to either side. 
• Queens: white has slightly more potential due to being able to move to a central square straight away. Otherwise the same. 
• Kings both require two moves to be castled. equal. 

 
So for development we can say that white is better. 

Piece Quality: Again white is favored here. White's pieces are fighting for multiple central squares, black's bishop is the only piece he has fighting for central squares. 

Material: equal.

So black's plan should involve doing at least one of the following:

1) increase space advantage

2) fight white's development advantage

3) fight white's piece quality advantage

I suggested two moves, Bxc3 and e6. 

Bxc3 undevelops white's knight and after the recapture undevelops black's bishop. The result is an increase in the space advantage for black but also an increase in white's development advantage and piece quality advantage. 

e6 solidifies d5 thus fixing white's central space advantage. It does nothing for the other two points.

I still believe the threats Nxd4 and Bb5+ are real and winning, and I see no other move but those two which address the threats.

Since e6 does nothing to make anything worse, I'd choose it over Bxc3.  

While I think loss by force is a bit of a stretch I'm gonna have to agree with you patzer that e6 is a better move. The queenside pawns would give white an advantage. e6 defends the pawn in the center solidifying the space advantage.  I'm still against Bxc3 I think its just a bad move for reasons I stated earlier.  It leaves white the bishop pair which is a clear  advantage here.  Plus you are giving up your dark squared bishop and leaving so many weak squares in front of your king.  This is more than compensation for the doubled pawns.  So I will stand corrected and go with e6 as the best move here as it avoids the complications e5 gives.  Bb7 is also a though although after Bb5+ black loses the ability to castle.

I think I agree with e6. It prevents tactical threats and unlike Bxc3 it does not hurt the position.

So can we agree that e6 is the best move here?  How does this work Phillip?  Do we just discuss it or do you give us the answer?

e5 seems to answer the problem

Guys I can not begin to tell you how proud I am, you really implement what I teach you and reach correct answers, even if they're not so intuitive- like in the given position. you have reached the answer e6 by a constructive thought process, and answered the requirements of our position. e6 is the best move here indeed, so well done!

In this position, Bxc3 could also be played, trying to simplify, but you had good reason to be doubtful about it. Your doubts were correct, regarding the global quality of pieces, however the trade-offs might be not so bad. so probably it would be the second choise here.

Again, well done!!! you see, you can now do it all by yourself!!!

Coach feels good about himself now