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1. 17 Dec '09 12:39
start of the game - do you do it?

if you go by points (which i usually do) 5 for the rook, 1 for the pawn and 3 each for the knight and bishop. equal. but is it?
2.  AThousandYoung
Gonzalo de Córdoba
17 Dec '09 14:55
TWO MINOR PIECES vs. ROOK AND PAWN(S)

All of the above applies with even more force to the case of two minor pieces vs. rook and pawns; the side with the rook wants very much to trade major pieces, even if he is a bit behind in material. Why this should be so is subject to debate; my explanation is that having more than one major piece is somewhat redundant - in many games there may only be time to employ one major piece on an open rank or file. Having at least one major piece (preferably a rook) to bring to an open line may be critical, but having two may be wasteful.

All in all, this section is a very important one; imbalances involving the Exchange are fairly common, and the effect of major piece trades on the evaluation is quite significant. While nearly everyone above novice level knows the value of the bishp pair, I suspect that even many masters are unaware of the above "principle of the redundancy of major pieces." As for rook and knight vs. two bishops and pawn, with nothing else but pawns on the board, the rook's side has a mild advantage, but add a rook to each side and the game is dead even. In general, with other pieces on the board, this imbalance should be considered even, with only a trivial edge for the rook's side.

How about the common situation of rook and pawn(s) vs. two minor pieces? My data shows equilibrium at 1½ pawns (slightly less when both minors are knights), assuming no bishop pair advantage. When the side with the minors has the bishop pair advantage, two pawn makes things about even (slightly better for the rook's side if he has one bishop, slightly worse if he has none).

For a good example of the accuracy of this statement, look up the main line of the Dilworth variation of the Open Ruy in any opening book. I think this evaluations are in agreement with the majority of grandmaster comments. As in the case of the Exchange, extra major pieces favor the minors, as do extra pawns. Here too we can adjust the fair value down by a quarter pawn when queens and one rook have been exchanged and up by a quarter when no major pieces have been traded.

By illustration, after 1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5 4.O-O Nf6 5.Ng5? O-O 6.Nxf7? (often seen in novice games) 6...Rf7 7.Bxf7+ Kxf7 material is even by traditional count, but the above considerations put Black a pawn and a quarter ahead, which is a fair assessment of the true [DH: material] situation. Actually the situation is even worse for White because no pawns have been exchanged, so the rooks' relative value is less than the average value would indicate. I have seen this exchange criticized on the grounds that White is trading off his developed pieces, but in my opinion this explanation is almost totally wrong, since the exposure of Black's king roughly compensates for the loss of a tempo or two by White [Here I must disagree with Larry. In fact, if anything White's king is in more danger since the open f-file gives the Black rook access to the kingside and Black has far more pieces ready to attack White's king, which is a primary reason for a king's lack of safety! And White lost more than a tempo, more like two or three since it took five bishop and knight moves to make the captures and Black did not lose a tempo with castling and only made two capturing moves with his rook and king. I discuss this position also with, of course, a similar conclusion to Larry's in my Novice Nook A Counting Primer.]

http://home.comcast.net/~danheisman/Articles/evaluation_of_material_imbalance.htm
3. 17 Dec '09 23:08 / 2 edits
I'll let them have my rook and pawn, I'll keep the knight and bishop thanks. You can always pick up pawns throughout the game, especially end game where coordinating the 2 pieces = win. Also you might have the bishop pair or at least an unnoposed light/dark square bishop.

Usually happens (to me anyway) when they have a bishop and knight attacking f7 or f2 and I castle kingside. Where if they trade they've just lost 2 developed pieces.
4. 17 Dec '09 23:33 / 3 edits
Originally posted by trev33
start of the game - do you do it?

if you go by points (which i usually do) 5 for the rook, 1 for the pawn and 3 each for the knight and bishop. equal. but is it?
Yes.At the start of the game the one giving up rook and pawn has the advantage.Problem is it's the other guy who needs to be willing to give up his N + B.

When the tiles start speaking to you it's time to see a doctor.
5.  irontigran
Rob Scheider is..
18 Dec '09 00:55
not only are 2 pieces better than 1, but the bishop and knight are great from the start, where rooks and pawns are more valuable in the endgame.. .

a tougher question would be- would you trade a B+N for a R+ 2 of the 4 central pawns?(cdef)
6. 18 Dec '09 10:00
Originally posted by Ajuin
When the tiles start speaking to you it's time to see a doctor.
you don't think it's too late?
7. 18 Dec '09 11:30
Originally posted by trev33
you don't think it's too late?
No.In fact,my doctor said it's ok to hear voices but I should come see her again if the voices start telling me to hurt people and/or small animals.
8.  Paul Leggett
Chess Librarian
18 Dec '09 14:35
Originally posted by Ajuin
No.In fact,my doctor said it's ok to hear voices but I should come see her again if the voices start telling me to hurt people and/or small animals.
"Acoustic Tiles" take on a whole new meaning...
9.  wormwood
If Theres Hell Below
18 Dec '09 14:39
Originally posted by AThousandYoung
TWO MINOR PIECES vs. ROOK AND PAWN(S)

All of the above applies with even more force to the case of two minor pieces vs. rook and pawns; the side with the rook wants very much to trade major pieces, even if he is a bit behind in material. Why this should be so is subject to debate; my explanation is that having more than one major piece is somewh ...[text shortened]... http://home.comcast.net/~danheisman/Articles/evaluation_of_material_imbalance.htm
seems like rubbish to me. sure you can pick up a position where dan's opinion holds, but generally... I don't think so. I think the choice depends so much on the position that giving any general recommendations will just induce errors.

and two major pieces on an open file being redundant, as a rule? what is that guy on??

I'd put this piece of advice in the same pile with dan's "lucena position isn't important".
10. 18 Dec '09 14:42
That is maybe a wrong interpratation....

Two majorn piecen on a open files, ( or semi-open are not good because they are on a open files, they need others factors ) .....

We often forget these factors.
11. 18 Dec '09 14:43
Originally posted by wormwood
and two major pieces on an open file being redundant, as a rule? what is that guy on??
i stopped reading it after that, my best attacks come when there's two (sometimes 3) major pieces on an open file.
12. 18 Dec '09 14:48 / 1 edit
Why don't you take a look at this game....

it show you why two rook on a open files are not the onlky thing that matter, the poor developpement of black, nearly all piece on first rank, also help the matter.... the trapped rook ..... which get captured by the kinght.....the rest, there is twenty way to win after that.

( Re1, ( the position is so great, white can do that.. )
13.  AThousandYoung
Gonzalo de Córdoba
18 Dec '09 16:06 / 1 edit
Originally posted by wormwood
seems like rubbish to me. sure you can pick up a position where dan's opinion holds, but generally... I don't think so. I think the choice depends so much on the position that giving any general recommendations will just induce errors.

and two major pieces on an open file being redundant, as a rule? what is that guy on??

I'd put this piece of advice in the same pile with dan's "lucena position isn't important".
He did a very thorough statistical analysis. This impresses me. That's a way to find patterns you might miss other ways.
14.  AThousandYoung
Gonzalo de Córdoba
18 Dec '09 16:13 / 3 edits
Originally posted by wormwood
seems like rubbish to me. sure you can pick up a position where dan's opinion holds, but generally... I don't think so. I think the choice depends so much on the position that giving any general recommendations will just induce errors.

and two major pieces on an open file being redundant, as a rule? what is that guy on??

I'd put this piece of advice in the same pile with dan's "lucena position isn't important".
This was written by GM Larry Kaufman and reprinted by Dan.

"first published in Chess Life March 1999; winner "Best Instruction" by the Chess Journalists of America"

Dan's rating of 2285 was too low to be part of the data set, by the way...
15. 18 Dec '09 16:18
Originally posted by trev33
start of the game - do you do it?

if you go by points (which i usually do) 5 for the rook, 1 for the pawn and 3 each for the knight and bishop. equal. but is it?
The easiest answer is that there are no points in chess. Just a win, a lose, or a draw.