< Earlier Kibitzing · PAGE 3 OF 3 ·
|Jun-30-08|| ||patzer2: <Manic> Look at the link above to the wikipedia article. It's a good one, and explains the different historical and modern piece point value scales in use. GMs Larry Kaufmann and Hans Berliner did separate computer evaluations and studies to determine the piece values. Kaufman came up with a 9.75 average, while Berliner had an 8.8 average. However, both GMs indicate the relative value of the Queen and other pieces depends upon the position and game situation.|
|Jun-30-08|| ||DarthStapler: Got it|
|Jun-30-08|| ||notyetagm: H Kramer vs J J Van Oosterwijk Bruyn, 1946|
White to play: 27 ?
click for larger view
27 ♗d4xg7! wins material.
Position after 27 ♗d4xg7!
click for larger view
Wow, Black was probably worried about a sacrifice on the f7-square but instead loses to a sacrifice on the g7-square.
White wins material because the White bishop is <TABOO>, as the Black g6-queen and g8-king will be <LINED UP> on the g-file for the <PIN> ♖f4-g4 if either Black royal piece takes the White g7-bishop.
27 ♗d4xg7! is a -TREMENDOUS- example of two important tactical principles:
1) Game Collection: King and queen are too valuable to defend (Nd--)
2) Game Collection: King and queen on the same line always means PIN
|Jun-30-08|| ||notyetagm: <patzer2: <zooter> Just to be sure, I looked up the chess piece point values on wikipedia. Here's everything I ever wanted to know about the subject but was afraid to ask:
P.S. Looks like the Queen's range of piece point values is today between 9.75 to 8.8. Fischer valued the Queen at 9 points and that's the most frequently used value as far as I know. Of course, the value of a piece will fluctuate based on the positional or tactical situation(s) at different points in the game.>
Wow, great link.
|Jun-30-08|| ||zooter: <patzer2: <zb2r> <The more interesting question is what happens if Black declines by 27. ... Re8 or 27. ... Qb1+.>|
If Black tries to avoid the loss of two points worth of material, Black loses quicker:
If 27... Rfe8, then White wins after 28. Rg4 Rd1+ 29. Kg2 Qe6 30. Qxe6 fxe6 31. Be5+ Kf8 32. Rf4+ Kg8 33. Rg7+ Kh8 34. Rg6#.
If 27... Qb1+, then Black loses after 28. Kg2 Kxg7 29. Rfxf7+! Kh8 (29... Rxf7 30. Qxf7+ Kh6 31. Qg7+ Kh5 32. g4+ Kh4 33. Qf6+ Kxg4 34. Rg7+ ) 30. Rxf8+ Rxf8 (30... Bxf8 31. Qc3+ Kg8 32. Rxb1 ) 31. Qd4+ Rf6 32. Qxf6+ Kg8 33. Qg7#>
wow, never even considered these lines and went straight for 27.Bxg7. So do I NOT get Monday's points!?!?
|Jun-30-08|| ||YouRang: After a few experiments with capturing the f7 pawn, I spotted 27.Bxg7, which wins a pawn and clears the 4th rank so that our rook can attack from g4 with protection from our queen.|
Looking a little deeper, it also weakens black's defense and initiates some mate threats. Of course, the bishop cannot be taken due to the queen-losing pin: Rg4.
It's a little unclear how either side would proceed, but in any case black is facing a number of threats (like Rxf7) and will probably have the have to jettison material to ward them off.
|Jun-30-08|| ||Marmot PFL: <1) Game Collection: King and queen are too valuable to defend (Nd--)|
2) Game Collection: King and queen on the same line always means PIN>
Good points, and would apply to yesterday's puzzle as well, the main difference being that there you had to invest a queen instead of a bishop. Interestingly, the game ended much more quickly after the combination on Sunday.
|Jun-30-08|| ||Amarande: Today seems a little difficult for a Monday, so I'm starting to wonder what the rest of the week will be like ...|
I considered Bxg7 briefly, but discarded it, as it didn't seem to be forcing enough, particularly for a "Very Easy." It is obvious that Black loses the Queen if he accepts the sacrifice, but it's not at all obvious that he has to accept it! As such, I kept trying to figure out something with Rxf7 and exploiting the resulting pin, but Black has f7 too well covered, there is not a way for White to make any real exploitation of the back rank after R(either)xf7 Rxf7, and as White's Bishop is on the dark squares, that won't work ...
|Jun-30-08|| ||playground player: That wasn't so easy! Even after White nails the Black Queen, plus a pawn, in return for a Rook and a Bishop--and that really is coming out ahead--he has to play carefully to get the win.|
|Jun-30-08|| ||234: Sunday puzzle <31. ?> Jun-29-08 Piket vs Smirin, 1993|
|Jun-30-08|| ||kevin86: A Peggy Lee problem:is that all there is?
White picks off a pawn-black cannot take the bishop without exposing the queen to a pin. So, it's a queen and pawn gained for a rook and bishop.
|Jun-30-08|| ||simsan: Maybe the people who feel silly today are the puzzle guys at Chessgames.com. :-) Somehow I feel that they must have missed some of complexities involved in ensuring the soundness of the Bxg7 sac.|
Like many others I saw the basic idea really quickly, and correctly determined that I was winning after both the Qb1+ as well as Qxg7/Kg7 responses. I did not see/think about the c5 idea. Still, due to the very unforced nature of the Bxg7 move (and the very non-monday feel to my solution), I felt very uncomfortable as I was clicking to browse through the game.
|Jun-30-08|| ||johnlspouge: Hi, <patzer2>. In response to your post lamenting the price of computer toys, I assume you know about the (free) endgame tables at |
Are there advantages to having the tables installed on your own machine?
|Jun-30-08|| ||patzer2: <johlspouge> I'm not sure if having the endgame table bases installed is an advantage or not. Some sources indicate they could adversely affect the performance of chess playing programs in other phases of the game. |
I'm aware of several internet table base endgame sites, but didn't have the one you gave. So thank you, and I've added it to my favorites.
I guess the advantage of having the table bases loaded into one's system would be not having to take the time to load and setup endgame positions on the internet. Also, if the tablebases did not affect a program's performance otherwise, it could I suppose enhance the performance of chess playing programs for analysis purposes.
P.S. Perhaps someone with a full set of toys, including quad or double quad processors, chess base, Rbyka and 6 piece endgame table bases can advise as to whether it creates any problems or not. Also would be interested in knowing if low end quad processors (under $1,000) work well with Rybka and these other toys.
|Jun-30-08|| ||MiCrooks: I get the confusion over declining...the win is easy if Black doesn't take the Bishop - Rg4 is going to be brutal.|
What interests me is that I am not absolutely convinced that this is a win a White. It probably should be but Black certain did not put up much of a defense. Moving the Rook over to the queenside out of play was suicide. White can do nothing on the Queenside, so the only hope is to do something with the pawn majority on the Kingside. With 4-2 there he should be able to make something happen, but if Black had kept his Rooks home maybe doubling on the d-file and sticking one on the 6th rank he might have been able to hold out.
Probably not, but what he played was silly.
|Jun-30-08|| ||TheaN: 1/1
Damn, what a hard Monday. I had my original post up until I closed the window by accident and I'm got going to type it again. I think that <patzer2> shows all important side variations, and although declining the sac wins easier, Qb1+ with Kxg7 is defenitely outside the Monday scope (although I did spot Rfxf7+ winning at least a second pawn for the piece). I'm giving myself the points for seeing all other variations, but I think the puzzle was misjudged.
|Jun-30-08|| ||ruzon: I think I would have played this OTB if it had been my game. And then I think I would have lost by allowing the c-pawn to get too close to queening itself. I'm still not quite sure how White wins from the final position, I'm guessing the threat is Qg4+ followed by Rb7-b6-h6.|
|Jun-30-08|| ||johnlspouge: <<TheaN> wrote: [snip] I had my original post up until I closed the window by accident and I'm got going to type it again. [snip] >|
I know the feeling. I type any serious post in Word, and only then cut-and-paste into the keyhole they give you here at chessgames.com.
To help preserve this post against deletion, I will add that our hosts have set up an amazingly well-organized site.
<Ferengi Rule of Acquisition #33: It never hurts to suck up to the boss.>
|Jun-30-08|| ||Fezzik: zooter: <patzer2>
Isn't a queen 8 points? At least that's what I read during my beginner chess course
Last time I checked, there's only one point given in chess, and that's to the victor. If a game is drawn, the players split the point.
This isn't just semantics, but an important part of understanding the value of chess pieces. We can talk about the chess pieces in relative terms.
For instance, a Queen and pawn are generally worth about as much as two rooks. The Queen is worth a little less than three minor pieces, depending on how well coordinated those pieces are.
The queen can stop most pawn chains as long as those chains are not advanced. Even the Queen needs the help of a second piece to deliver checkmate. I don't know how many "points" a Queen is worth. Even the value of a pawn changes over time and space!
I hope this pedantry finds a good home.
|Jun-30-08|| ||Sneaky: A queen is 8 points? Nonsense! The debate, if there is one, is whether a queen is worth 9 points or 10 points.|
In the 10 point camp the argument is that a queen for two rook is generally considered an equal trade. Ergo, a queen is 5+5 or 10.
In the 9 point camp, it's pointed out that positions of a ♕♙ vs ♖♖ are generally drawn, therefore the Queen is not quite as good as two rooks. ♕♙♙ vs ♖♖ however is bad news for the rooks. Ergo, a queen is 9.
I lean towards thinking "9 points" most of the time, but the true answer is in the position itself: sometimes a queen is fierce but other times the rooks are in control.
|Jul-01-08|| ||patzer2: <Fezzik> Thanks for the comment. I took it as a phlosophical and humorous way of emphasizing a point about not getting too overly concerned with rigidly calculating piece values or maintaining material balance at the expense of fully assessing the position for winning potential. However, I also assume you give your students a bit more specific instruction on how to value the pieces when calculating captures and material exchanges.|
<Sneaky> I agree with your comments about the point values for the pieces, but I suspect Coach Fezzik was just humourously emphasizing that the value of Chess pieces is relative to the game situation, and sometimes is irrelevant as in sacrificing material in a mating combination to score "the one point that really counts."
|Jul-01-08|| ||ravel5184: These are my point standings for pieces!
Pawn = 1.5
Knight = 3
Bishop = 3
Rook = 4.5
Queen = 8.5
Of course as the board starts to empty, the Pawns are worth more. A King and Bishop can hardly hope to checkmate against a King and Pawn(s)!
|Jul-01-08|| ||ravel5184: Oh me stupid!!
Me see that me win with Knight vs. two Pawns against computer and me lose with three Pawns vs Rook! So me say:
Pawn = 1.125!!
Then you would need at least four Pawns to cope with a Rook, while three Pawns is usually worth slightly more than a Bishop/Knight.
Although on an empty board, three Pawns can usually beat a Rook.
|Jul-01-08|| ||ravel5184: P.S. On ChessMaster 9000, "Jessica" says Pawns are worth 3.0!! I can beat the heck out of her! Now I know why!|
Me have my own personality on ChessMaster9000 who says Pawns are worth 1.5 and Bishops 2.5!! And his strength of play is 100! And I will now see if he can cope with some strong opponents!
That's what me do all day!
|Jul-01-08|| ||ravel5184: Now me know why me always lose when me take on g4 twice with Knight and Bishop!|
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