quuen sac for two rooks

newenglandsun · Post by **newenglandsun** » Fri Dec 04, 2015 11:31 pm

Dann Corbit · Post by **Dann Corbit** » Sat Dec 05, 2015 12:40 am

It's generally not considered a sacrifice to give up a queen for 2 rooks, because 2 rooks are better than a queen.

Dann Corbit · Post by **Dann Corbit** » Sat Dec 05, 2015 3:05 am

the analyzed moves of the game:
https://www.dropbox.com/s/l7q93erz550ew ... r.epd?dl=0

Nordlandia · Post by **Nordlandia** » Sat Dec 05, 2015 3:27 am

Dann Corbit wrote:It's generally not considered a sacrifice to give up a queen for 2 rooks, because 2 rooks are better than a queen.

«A natural assumption is that the two rooks will be stronger than the queen in the majority of positions; another is that a material balance is struck when the side with the queen has an extra pawn. I must admit that, when I examined top-flight games from my database, I was surprised to see that the queen outscored the rocks. I would have predicted a small edge for the rocks but in fact the side with the queen managed 55%»

From a statistical viewpoint, 55% is equivalent to home field advantage in soccer or advantage of playing white.

«The Queen is weaker than two Rooks if the hostile King is protected against Checks, otherwise it may be stronger. Ceteris paribus, it would appear that the Queen is trifle weaker than two Rooks»

Definition of trifle "something that does not have much value or importance"
"With other things the same" or "other things being equal or held constant"

Dann Corbit · Post by **Dann Corbit** » Sat Dec 05, 2015 3:35 am

These are the values used by stockfish (researched with hundreds of thousands of games played):

RookValueMg = 1270, RookValueEg = 1281,
QueenValueMg = 2521, QueenValueEg = 2558,

since 1270*2-2521=19
and 1281*2-2558=4

it appears that they are close enough in value (just counting the wood and ignoring that a pair can support one another -- there are, of course, many other interactions that may weight the value one way or another) to be a toss-up.

Nordlandia · Post by **Nordlandia** » Sat Dec 05, 2015 4:23 am

Dann Corbit wrote:These are the values used by stockfish (researched with hundreds of thousands of games played):

RookValueMg = 1270, RookValueEg = 1281,
QueenValueMg = 2521, QueenValueEg = 2558,

since 1270*2-2521=19
and 1281*2-2558=4

it appears that they are close enough in value (just counting the wood and ignoring that a pair can support one another -- there are, of course, many other interactions that may weight the value one way or another) to be a toss-up.

You're right 1281 (x2) = 2562/2558 =1,00156 which is statistically meaningless.

Do you know the value Stockfish used in case "The exchange" and bishop pair.

Dann Corbit · Post by **Dann Corbit** » Sat Dec 05, 2015 5:49 am

Nordlandia wrote:
Dann Corbit wrote:These are the values used by stockfish (researched with hundreds of thousands of games played):

RookValueMg = 1270, RookValueEg = 1281,
QueenValueMg = 2521, QueenValueEg = 2558,

since 1270*2-2521=19
and 1281*2-2558=4

it appears that they are close enough in value (just counting the wood and ignoring that a pair can support one another -- there are, of course, many other interactions that may weight the value one way or another) to be a toss-up.
You're right 1281 (x2) = 2562/2558 =1,00156 which is statistically meaningless.

Do you know the value Stockfish used in case "The exchange" and bishop pair.

Don't know. In actual runtime behavior, there are many different factors that create the evaluation.

quuen sac for two rooks

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