Thorsson: <Domdaniel: We've had some debate about whether the exchange of dark square bishops is a good thing (or not)>

I'm pretty sure it's not that good in general. Black has enough defensive resources to defend his dark squares if there are no DSBs.

But there will be specific situations where exchanging the Bishops leads to something good. Perhaps to distract another piece, or to gain (not lose) a tempo.

One of our small positional advantages lies in the fact that we have no pressing need to play d4. Black, on the other hand, has a Bishop hemmed in by his d6-pawn, and may want to play ...d5 to free it. Of course, with his last move ...Rfe8, he also gave the Be7 a different option, of retreat to Bf8 when the time is right, and then a possible redeployment at g7.

Still, on balance, he's more likely to play ...d5 (blocking his other bishop on c6) than we are to play d4. d4 is important to us as a pivot - either a knight or bishop can occupy it, or both in succession. Equally, though, Black can use d5 for his pieces, eg ...Nd5.

It seems clear that a d-pawn advance by either side would need to be immediately blockaded. He can't let us play d3-d4-d5, and we can't let him play d6-d5-d4.

Positions where both sides have an IQP (isolated d-pawn) are pretty common - most of us have played games with pawns on d4 and d5. What's unusual here is that the pawns are still back on d3 and d6 - which makes everything quite different.

<Domdaniel>
<Ron>
<whiteshark>
<FH Bradley>

<Chess Classics> is now hosting the 19.h3 workshop.

Seeing as most of you are asleep (or should be!), I've copied, with <Dom>'s tacit approval) the discussion starting with <Open Defence>'s comment about the weakness surrounding White's King after 19.h3 and finishing with <Domdaniel>'s post immediately before this post into User: Chess Classics 's forum, to continue this discussion.

Please post any further analysis and discussion at CC's place.

This workshop will now resume transmission as the <Strategy Forum>

click for larger view

This is the position after

Apologies for leaving you off the mailing list in that post, that was very careless of me.

You might like to copy and post your recent messages here into <CC>'s forum for continuity.

18.Qd2 Rfe8 19.Bb6 Ng4 20.Nd4 Bf8 21.Qf4 Ne5 22.Nxc6 bxc6

with this position:

click for larger view

I am not sure why the computers rate this line so much better for White.. but strategically we will have to advance d4 - d5 and once Black can play Ne5-c4xb6 our DSB is gone.. so unless we can prevent this sequence tactically we must be strategically wary of 19Bb6 IMHO

We must have a fresh look at 19Bb6 looking at the idea of Ng4-e5-c4 and x b6 .. which is a strategic victory for Black..IMHO.. lets see.. maybe this post belongs on <YouRang's> forum ?

<Open Defence> - From my reading and participation on the main thread today, I would have to agree with you 100%. Dionyseus also has ome very important analysis on the main thread in support of this contention.

So I've deleted most of the 19.h3 posts here, having checked that they'd safely made the journey across to CC's place. I've also left in a few that seemed to have strategic or positional implications.

Back to strategy, then.

I agree with those analysts who found such excellent material in the 'Monad Trap' line, after 19.Bb6 Nd5 20.Bd4 gxf5, after which things get hairy for Black.

My problem is with the start of the line, and Black's first two moves, 19...Nd5 and 20...gxf5. If they lead to trouble then AN is bound to play something else.

I championed the idea of Bb6 followed by Bd4 ages ago, when Bb6 still attacked the Black Queen and was therefore a way of gaining tempo. Now I'm not so sure - if we're going to spend two moves playing Bd4, why not play (19 & 20)h3 & Bd4, in whichever order? Or Bd4 along with some other useful move?

I haven't yet checked thru all the main-page analysis of this line that was done while I was asleep, so I'd better do that now before I make a fool of myself.

In the first place I don't see the line by Dionyseus 21..Nd7 22. Qf2 actually leading to a forced loss..but since I dont use computers I most likely am wrong.. but can't Black simply play 22..Ne5 23.Qg3 Kh8 24.f6 Rb8 25. Qg5 Nd7 26. Nf5 Nxf6 27.Nh6 Kg7 it seems we are a piece short for our attack to succeed in fact a DSB short!!

click for larger view

I'm glad you apparently agree re the Monad Trap: the better it looks, the less likely that GMAN will go along with it. I still think that a combination of Bd4 and h3, in whatever order, might be a good alternative. Although 19.Bb6 is certainly the best of the three leading moves, I think.

As for the DSB-trade, I now tend to agree with Thorsson's post which I quoted earlier - if both bishops go, Black has sufficient defensive resources. But there are particular situations where the trade is good for us.

(0.35): 19...Bd8 20.Nd4 Ng4 21.Bxd8 Qxd8 22.Qf4 Ne5 23.Rad1 g5 24.Qg3 f6 25.Ra1 b5 26.Ne6

Tomlinsky: - The Tale of the Dark Squared Bishop -

This is puzzling me greatly. We all have a lot of energy invested in our glorious dark squared bishop and personally I want something tangible in return for giving it up. A number of questions present themselves but for the moment the sub-plot I would like answering is summarised thus:

1) The World plays 19.Nd4 and we lose our important dark squared bishop at Nickel's option. It is blocked on one of it's main diagonals.

2) The World plays 19.Bg5 and we lose our important dark squared bishop at Nickel's option having wasted a move in order to do so. Either that or the bishop retreats admitting that the previous move was flawed.

Take a look at the board for a few seconds. That bishop is quite arguably the most potent piece on the it at the moment. We gave it power and flexibility to be made use of I assume at some point?

Is there some train of universal logic that someone would care to impart to me on why giving it away is apparently such a great idea for little reward? What am I missing here? I have not seen ONE piece of analysis that shows any advantage worth giving it up for. Not one single shred whatsoever. I have asked for an overall rationale but diversion tactics from proponents prevail.

Long ago, I mentioned 'Thorsson's Law of Pragmatism' (so named because Thorsson had concisely cited pragmatism as a counter to some traditional chess maxims that were being quoted). In essence, it says: play what works, even if it looks funny.

Since then I've come across similar comments by GMs and chess writers, usually with reference to stylistic changes since the advent of strong computers. Something has changed in chess in the last 10 or 15 years, and many of our 'instinctive' positional truisms are slightly out of kilter as a result. The top players have seen how engines spot deep tactical resources in 'bad' positions, and how computer analysis can turn up strange new possibilities.

This leads to a new way of playing - especially potent in CC/centaur games like this, where engines and human brains are combined. The overall effect is as significant as the 'hypermodern' discoveries of Reti and Nimzowitsch. There have been other strategical 'revolutions' like the 'soviet exchange sac' or the exploration of Black's resources in the King's Indian - but the engine revolution and the Law of Pragmatism is the most far-reaching.

Interestingly, computers - because of the 'values' programmed into them - sometimes make the same mistakes as humans, eg mis-evaluating the longterm significance of an exposed king or a bishop pair. But computers can correct these errors by reaching deeper into the position and seeing, for example, that the exposed king is actually safe.

<ganstaman> made this point on the main page, as an aside to the debate about 19.Bb6 followed by Bd4, as opposed to an immediate 19.Bd4:

As a result, many of the dynamics of the position are very different - while we also have to keep looking at the possibility of d3-d4-d5 by white, or d6-d5-d4 by black.

I once lost a long ending (B vs N) to an IM who had an isolated pawn on d3. He didn't advance it, as I thought he would, but used the square d4 as a pivot for his knight, and later his king, gradually increasing his control of the centre. Even though there were also pawns on both flanks - and I'd gone into this ending expecting my bishop to be better - I was slowly tied down, and the bishop was reduced to protecting loose pawns on each wing. He finally won by giving up the knight for 2 pawns, in a position where my K+B could not catch both his passed pawns.