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Álvaro Begué

Joined: 09 Mar 2010
Posts: 800
Location: New York

Post subject: Re: see    Posted: Tue Nov 28, 2017 1:49 pm

flok wrote:
 tomitank wrote: 100 - 975 + 325 - 325 + 325 = 550

 AlvaroBegue wrote: No, that's not it at all. It's -550. I can break it down if you can't figure it out. But don't start with the material value of the queen, because the pawn is the first thing to go.

Please do because I can't figure it out.
First of all: why an odd number of additions? there are 6 pieces?

But there are only 5 captures.

Let's imagine the sequence of moves if everyone captures everything till the end (although they don't have to: Either player could stop and take the "stand pat" score, like in quiescence search).

qxP, Nxq, nxN, Nxn, nxN

Let's write down the sequence of captured piece values, with sign:
+100, -975, +325, -325, +325

Now compute the partial sums (material balance at each step):
+100, -875, -550, -875, -550

Now start at the penultimate place in the list (the second -875) and think of whether the player to move would prefer the material balance at that time (the number we are looking at) or the result of the recapture (the next element in the list).

+100, -875, -550, >>-875<<, -550

In this case it was black's turn, and black would rather see -550 than -875, because in the convention of signs we are using in this post, higher means better for black. So we replace the -875 with -550 and we move back.

+100, -875, >>-550<<, -550, -550

White is indifferent as to whether to pick the -550 from not standing pat or the -550 from recapturing.

+100, >>-875<<, -550, -550, -550

It's black's turn, so black would rather take the -550 from recapturing.

>>+100<<, -550, -550, -550, -550

It's white's turn, so -550 is better than +100.

-550, -550, -550, -550, -550

The result of SEE is the first number, so -550.
 Display posts from previous: All Posts1 Day7 Days2 Weeks1 Month3 Months6 Months1 Year Oldest FirstNewest First
Subject Author Date/Time
Folkert van Heusden Tue Nov 28, 2017 1:11 pm
Álvaro Begué Tue Nov 28, 2017 1:30 pm
Folkert van Heusden Tue Nov 28, 2017 1:38 pm
Tamás Kuzmics Tue Nov 28, 2017 1:43 pm
Re: see Álvaro Begué Tue Nov 28, 2017 1:49 pm
Tamás Kuzmics Tue Nov 28, 2017 1:32 pm
Marco Belli Tue Nov 28, 2017 3:26 pm
Álvaro Begué Tue Nov 28, 2017 3:58 pm
Marco Belli Tue Nov 28, 2017 4:35 pm
Folkert van Heusden Tue Nov 28, 2017 7:34 pm
Peter Österlund Tue Nov 28, 2017 8:11 pm
Steve Maughan Tue Nov 28, 2017 9:36 pm
Folkert van Heusden Wed Nov 29, 2017 5:03 pm
Steve Maughan Wed Nov 29, 2017 5:16 pm
Sven Schüle Wed Nov 29, 2017 8:49 pm
Álvaro Begué Wed Nov 29, 2017 9:00 pm
laurie tunnicliffe Thu Nov 30, 2017 2:01 am
Álvaro Begué Thu Nov 30, 2017 5:07 am
laurie tunnicliffe Thu Nov 30, 2017 5:43 am
Álvaro Begué Thu Nov 30, 2017 11:47 am
Richard Delorme Thu Nov 30, 2017 12:44 pm
Maarten Claessens Wed Nov 29, 2017 9:11 am
Folkert van Heusden Wed Nov 29, 2017 9:20 am
Marco Belli Wed Nov 29, 2017 9:50 am
Folkert van Heusden Wed Nov 29, 2017 2:00 pm
Maarten Claessens Wed Nov 29, 2017 10:34 am
Álvaro Begué Wed Nov 29, 2017 11:33 am
Tony Soares Fri Dec 01, 2017 10:51 am

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