donderdag 31 december 2009

Stoyko and Phaedrus combined

This afternoon I struggled with the position below. If you want you can use it yourself as a Stoyko exercise. The position is taken from Khmelnitsky's Chess Exam.

After you have analyzed the position and written down every line, you can compare it with Khmelnitsky's analysis. If you highlight the space between the brackets you can see the line he recommends for white in this position.

(This is Khmelnitsky's analysis: 1 Rxd6!? was played in the game Baburin - Basas, Andora 1998. White got two pawns for the piece, neutralized blacks initiative, and gainde psychological momentum. Black never recovered from the initial shock and quickly fell apart. After 1 ... fxe3 2 Nxe3 Bf8? [already a losing move. Better was 2 ... Nf6, but after 3 Rc6 and 4 Rxc5 white has excellent chances.] 3 Rxg6! hxg6 4 Qxg6+ Ng7 5 Ng4 Be7 6 Nh6+ Black resigned)

When I had checked my analysis with Khmelnitsky's solution, I tried to win this position with the move recommended by the author and using my own Phaedrus Exercise. It was really challenging. Amazingly enough I already had real trouble winning this against Fritz 10 with a fixed depth of 3 ply.

12 opmerkingen:

From the patzer zei

I first thought of Rxd6 but dismissed it since i disliked giving away my bishop so my move would be Bd2. I doubt i could win that position even following the authors move suggestion.

Phaedrus zei


I am intrigued!


I heartily recommend you try to win against an chess engine using fixed depth. Start at ply 3, but if this is too hard, try again with ply 1.

Another way to keep trying to get to the heart of the position is change colors. And again start at ply 1 or 3.

It is strange, but playing out these positions against increasing opposition creates a deeper impact than doing the Stoyko exercise.

Temposchlucker zei

Rybka suggests Be4 (+0.77)
While Bc1 = +0.71 and
Rxd6 = +0.38

Sometimes I think this is just all too difficult to me. At the mean time I noticed that Khmelnitsky failed to check his analysis with a computer. Which makes some exercises less conclusive. This is one of them.

I will have a look at the Phaedrus exercise.

Phaedrus zei


Thank you for providing Rybka's assessment. After the Stoyko, I chose 1. Bc1, and it is reassuring to know that this is Rybka's second choice.

Your spot on observation that the analysis of Khmelnitsky is not conclusive, is exactly why this position is ideal for the exercises I did. The only thing that is lacking is a thorough analysis of the author of the position after 1. Rxd6.

When I tried to win the position after the exchange sacrifice I noticed how difficult that was. But when I tried to defend it, I again hard great difficulty to compete at even ply 3 level.

Yes, the position after 1. Rd6 is very dynamic and difficult to play for both sides. In the end I think that this is the reason why Baburin chose to play the sacrifice. Not the objective strength of the move, but knowing that he would get excellent winning chances against his 2125 rated opponent, who would most likely not be able to master the complications after 1 Rxdd6 as well as he did.

It seems to me that you are right and that Khmelnitsky did not check his analysis with a computer.

I also noticed something else which made me question the book (and its author) a bit. In the table with results for this particular exercise, the score of players with a rating of 2400/2800 is 97%. But I find it very hard to believe that he actually found at least 30 players with ratings up to 2800 (so even at least one player with a rating of 2700+), to do this exam.

Blue Devil Knight zei

How do you set the ply of Fritz like that when you play him?

Anoniem zei

Always read stuff that will make you look good if you die in the middle of it.............................................

Phaedrus zei


This is the way Fritz is set to ply level: Click "game" on the upper toolbar, than click "levels" and than go to "fixed depth".

Good luck.

Robert Pearson zei

Hello Phaedrus! Dept. of FWIW: I reopened my old chess blog, minus the politco/philosopho blathering, at Robert Pearson's Chess Blog.

Robert Pearson zei

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Best regards,

Robert Pearson

Robert Pearson zei

The first installment of the best of chess blogging Carnival is up! The Best Of! Chess Blogging, Part I: Openings

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