How powerful is the Queen compared to 2 Rooks ?

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Chessqueen
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Re: How powerful is the Queen compared to 2 Rooks ?

Post by Chessqueen » Sun Jan 27, 2019 10:28 pm

Nordlandia wrote: ↑
Sun Jan 27, 2019 4:37 pm
 Chessqueen: A rook value of 4¾ is is my preferred value over 4½.

Pawn = 1.0
Knight = 3.0
Bishop = 3.25 (per Fischer)
Rook = 4.75
Queen = 9.5 ?
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King ~ 3.00 in the endgame.
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I agree more with Fischer valuation of the chess pieces, and I found out this in Wikipedia, but I disagree that the two Rooks are slightly more powerful in the endgame.

Changing valuations in the endgame
As already noted when the standard values were first formulated (Lolli 1763:255), the relative strength of the pieces changes as a game progresses to the endgame. The value of pawns, rooks and, to a lesser extent, bishops may increase. The knight tends to lose some power, and the strength of the Queen may be slightly lessened, as well. Some examples follow.

A queen versus two rooks
In the middlegame, they are equal
In the endgame, the two rooks are somewhat more powerful. With no other pieces on the board, two rooks are equal to a queen and a pawn
A rook versus two minor pieces
In the opening and middlegame, a rook and two pawns are weaker than two bishops; equal to or slightly weaker than a bishop and knight; and equal to two knights
In the endgame, a rook and one pawn are equal to two knights; and equal to or slightly weaker than a bishop and knight. A rook and two pawns are equal to two bishops (Alburt & Krogius 2005:402–3).
Bishops are often more powerful than rooks in the opening. Rooks are usually more powerful than bishops in the middlegame, and rooks dominate the minor pieces in the endgame (Seirawan 2003:ix).
As the tables in Berliner's system show, the values of pawns change dramatically in the endgame. In the opening and middlegame, pawns on the central files are more valuable. In the late middlegame and endgame the situation reverses, and pawns on the wings become more valuable due to their likelihood of becoming an outside passed pawn and threatening to promote. When there is about fourteen points of material on both sides, the value of pawns on any file is about equal. After that, wing pawns become more valuable (Berliner 1999:16–20).
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Nordlandia
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Re: How powerful is the Queen compared to 2 Rooks ?

Post by Nordlandia » Mon Jan 28, 2019 1:12 am

Graham Banks wrote: ↑
Sun Jan 27, 2019 8:58 pm
Chessqueen wrote: ↑
Sat Jan 26, 2019 1:18 am
 ...I am convinced that a Queen is more powerful than two Rooks
From my observations over many years of watching engines playing, in general the queen has the edge.
What about three minor pieces vs two rooks?
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Graham Banks
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Re: How powerful is the Queen compared to 2 Rooks ?

Post by Graham Banks » Mon Jan 28, 2019 2:55 am

Nordlandia wrote: ↑
Mon Jan 28, 2019 1:12 am
Graham Banks wrote: ↑
Sun Jan 27, 2019 8:58 pm
Chessqueen wrote: ↑
Sat Jan 26, 2019 1:18 am
 ...I am convinced that a Queen is more powerful than two Rooks
From my observations over many years of watching engines playing, in general the queen has the edge.
What about three minor pieces vs two rooks?
Three pieces are generally more useful than two, but not much between these.
Two minors almost always do better v rook and extra pawn though.
gbanksnz at gmail.com
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Nordlandia
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Re: How powerful is the Queen compared to 2 Rooks ?

Post by Nordlandia » Mon Jan 28, 2019 10:26 am

While two bishops + two pawns is stronger than rook and knight.

Example position: Stockfish is capable of beating Komodo as white here.

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Chessqueen
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Re: How powerful is the Queen compared to 2 Rooks ?

Post by Chessqueen » Mon Jan 28, 2019 2:08 pm

Nordlandia wrote: ↑
Mon Jan 28, 2019 1:12 am
Graham Banks wrote: ↑
Sun Jan 27, 2019 8:58 pm
Chessqueen wrote: ↑
Sat Jan 26, 2019 1:18 am
 ...I am convinced that a Queen is more powerful than two Rooks
From my observations over many years of watching engines playing, in general the queen has the edge.
What about three minor pieces vs two rooks?
Here is GM Karpov versus GM Boris Gulko, but I will also let SF10 play it out by itself = Program with same strength to see if Karpov held it because of his superior rating. In the game that I will show you SF10 vs SF10 it will also show you that a Knight and Bishop versus a single Rook is stronger with same amount of pawns 4 on each side.
https://www.youtube.com/watch?v=Y5-D7vXtaUo

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Re: How powerful is the Queen compared to 2 Rooks ?

Post by lkaufman » Mon Jan 28, 2019 4:48 pm

With no minor pieces on the board and an average number of pawns (five per side), two rooks are nearly a pawn better than the queen. But on a full board the queen is indeed better than two rooks, as GM Roman Dzindzichashvilli taught me before computers were strong enough to answer the question. On average thruout the game the queen is a bit weaker.
Komodo rules!
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Nordlandia
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Re: How powerful is the Queen compared to 2 Rooks ?

Post by Nordlandia » Mon Jan 28, 2019 7:05 pm

lkaufman wrote: ↑
Mon Jan 28, 2019 4:48 pm
 With no minor pieces on the board and an average number of pawns (five per side), two rooks are nearly a pawn better than the queen. But on a full board the queen is indeed better than two rooks, as GM Roman Dzindzichashvilli taught me before computers were strong enough to answer the question. On average thruout the game the queen is a bit weaker.
Maybe "reinfeld values" need to be renewed for engine play. Reinfeld values is still good enough for human play i suppose.
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Re: How powerful is the Queen compared to 2 Rooks ?

Post by Dann Corbit » Mon Jan 28, 2019 7:48 pm

One problem in this thread is data.
You can't prove a point based on a single game.
You can't prove a point based on a hundred games.
You have a bit of probability in your favor after a thousand games.

Here is what Stockfish says about the value of chessmen (note that pawns are not 100) during the midgame and during the endgame:

Code: Select all

    PawnValueMg   = 136,   PawnValueEg   = 208,
    KnightValueMg = 782,   KnightValueEg = 865,
    BishopValueMg = 830,   BishopValueEg = 918,
    RookValueMg   = 1289,  RookValueEg   = 1378,
    QueenValueMg  = 2529,  QueenValueEg  = 2687,
Note that two rooks are 2578 so a bit better than the queen in midgame. But it's close enough where it doesn't matter much.
Note that two rooks are 2756 so significantly better than the queen in the endgame.
It appears that Stockfish's lips are sealed about the value in the opening.

The point totals here are based on careful experiments with lots of games.

I guess that Larry has done a careful calculation too. He did, after all, write the book on imbalances. Literally.

In addition, chessmen can change their values based on special conditions.
Edge pawns are wimps in the opening and tigers in the endgame.
If there is a giant row of locked pawns, I once heard a king moan, "Half my kingdom for a knight!"
So all the generalities have exceptions anyway.
Taking ideas is not a vice, it is a virtue. We have another word for this. It is called learning.
But sharing ideas is an even greater virtue. We have another word for this. It is called teaching.
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Nordlandia
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Re: How powerful is the Queen compared to 2 Rooks ?

Post by Nordlandia » Mon Jan 28, 2019 8:16 pm

Ceteris paribus, shouldn't the idea about major piece redundancy nullify the two rook advantage in material. After all neither Rook does anything that the other one can't do. Maybe the minus effect is not so apparent for the rooks as compared to two knights and particularly two queens.
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Re: How powerful is the Queen compared to 2 Rooks ?

Post by Dann Corbit » Mon Jan 28, 2019 10:46 pm

Two rooks have a certain synergy together.
E.g.
One rook on the 7th is good. Two rooks on the 7th rank is savage. Utter devastation is just around the corner.
E.g.
Endgame KRRvk compared to KRvk
Both times the side with rook(s) win, but you can win much faster if the weaker king starts in the center of the board with 2 rooks than with 1.
They are also great for battery (e.g. Alekhine's gun variants).
If you have to have a duplicate of something then a queen would be wanted because of her power.
But if you could not have a queen, I would pick a rook, unless there was a driving reason to pick something else (e.g. one of those kinky knight underpromotion only mates).
Taking ideas is not a vice, it is a virtue. We have another word for this. It is called learning.
But sharing ideas is an even greater virtue. We have another word for this. It is called teaching.
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