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Subject: Static evaluation after the "Positional/Real Sacrifice"

Author: Andrew Williams

Date: 05:49:19 12/03/99

```Over the last few days, I have been fascinated by the discussions on CCC
about positional sacrifices. Some of the discussion has centred on the value
assigned to the attack that is obtained after the sacrifice and I was wondering
how other programs evaluated the position after Hossa's sac:

r3q1k1/ppp1rp2/2n1b2Q/8/2P5/3B4/PPP2RPP/5RK1 b - - 0 2

This is after 1. Bxh6 gxh6 2. Qxh6 from the original position posted by
Peter McKenzie. PostModernist's static evaluation of the position is presented
below. Essentially, it thinks that White is winning by 0.71. The ATTACKTOTAL
score is generated by analyzing the squares around the King to see how many of
them are attacked and what sorts of pieces are attacking them. Please note that
not all the factors that contribute to PM's score are included in the output
below.

Could other programmers post similar information? I believe that even an
overall static evaluation would be interesting.

Cheers

Andrew Williams

SCORE ANALYSIS
BLACK to move

MATERIAL -137 (Positive means WHITE has more material) W:19086 B:19223
Game stage M
Actual moves played: 1 (halfMoves=1)

Fifty move counter: 0

r=547      #       #       #    q=1040     #    k=15939    #

o=103   o=106   o=103      #    r=565   o=94       #       #

#       #    n=346      #    b=346      #       #    Q=1022

#       #       #       #       #       #       #       #

#       #    P=101      #       #       #       #       #

#       #       #    B=344      #       #       #       #

P=103   P=103   P=98       #       #    R=553   P=103   P=115

#       #       #       #       #    R=555   K=15993    #

HCW=1   HCB=1
cannotCW=1      cannotCB=1
CCRW=0  CCRB=0

Piece Bonuses White=4   Piece Bonuses Black=-34

KINGEXPOSURE WHITE=3    KINGEXPOSURE BLACK=16
DANGERSQUARES WHITE=0   DANGERSQUARES BLACK=5
ATTACKINGFORCE WHITE=21 ATTACKINGFORCE BLACK=0
ATTACKTOTAL WHITE=240   ATTACKTOTAL BLACK=0

EVALUATION : 71 (positive means WHITE is winning)

```