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tempo hit / match score matters..

Posted: Thu Dec 22, 2022 12:38 pm
by admin
Here is a position from YouTube video "Northwest Indiana Backgammon Association, December 2022 Monthly Tournament. Charlie v. Dujuan Round 1"


Position on video is at 24 :43

White on roll to play 6-1
5 pt match score 1-2 white trailing
pips 114 / 128

Image

So white played 10 -3 which seemed like a reasonable move but xg analysis threw a fit, got all twisted and declared a 4x blunder :o gnubg rollout concurs

gnubg 4 ply likes 7/1* 6/5 as did XG but gnubg rollout prefers 24/23 7/1* close only -.034 diff

But look what happens when the scores are reversed.
If you are leading 2-1 you definitely DON'T want to leave 2 blots in your home board. rollout says it would be .108 blunder.

Tricky position in particular the score aspect

This kind of hit on the ace pt 7/1 is known in backgammon lingo as a "tempo hit" which the 7/1 hit on the ace pt is a good example of such a move. The term is explained nicely at https://thegammonpress.com/backgammon-l ... tempo-hit/ with a good explanation of when to use it and when not to use it.


=============================== gnubg 4 ply and rollouts for both scores==============

======12===============================

1. Cubeful 4-ply 7/1* 6/5 Eq.: -0.075
0.393 0.208 0.006 - 0.607 0.202 0.020

2. Cubeful 4-ply 24/23 7/1* Eq.: -0.087 ( -0.011)
0.395 0.190 0.005 - 0.605 0.161 0.015

3. Cubeful 4-ply 10/4 6/5 Eq.: -0.294 ( -0.218)
0.371 0.148 0.005 - 0.629 0.149 0.009

4. Cubeful 4-ply 10/9 7/1* Eq.: -0.347 ( -0.272)
0.360 0.158 0.004 - 0.640 0.156 0.012

5. Cubeful 4-ply 7/1* 2/1 Eq.: -0.393 ( -0.318)
0.347 0.156 0.003 - 0.653 0.164 0.013

6. Cubeful 4-ply 24/23 10/4 Eq.: -0.395 ( -0.319)
0.368 0.111 0.003 - 0.632 0.129 0.006

7. Cubeful 4-ply 7/6 7/1* Eq.: -0.413 ( -0.338)
0.349 0.140 0.003 - 0.651 0.142 0.009

8. Cubeful 4-ply 10/3 Eq.: -0.485 ( -0.409)
0.337 0.106 0.003 - 0.663 0.135 0.007




==================

1. Rollout 24/23 7/1* Eq.: -0.024
0.403 0.197 0.013 - 0.597 0.168 0.020 CL -0.086 CF -0.024


2. Rollout 7/1* 6/5 Eq.: -0.059 ( -0.034)
0.391 0.204 0.008 - 0.609 0.203 0.031 CL -0.312 CF -0.059


3. Rollout 10/4 6/5 Eq.: -0.268 ( -0.244)
0.371 0.156 0.009 - 0.629 0.154 0.013 CL -0.271 CF -0.268


4. Rollout 10/9 7/1* Eq.: -0.322 ( -0.297)
0.366 0.165 0.008 - 0.634 0.155 0.015 CL -0.292 CF -0.322


5. Rollout 7/1* 2/1 Eq.: -0.379 ( -0.354)
0.353 0.165 0.008 - 0.647 0.166 0.017 CL -0.338 CF -0.379


6. Rollout 7/6 7/1* Eq.: -0.385 ( -0.361)
0.355 0.148 0.005 - 0.645 0.144 0.013 CL -0.318 CF -0.385


7. Rollout 24/23 10/4 Eq.: -0.430 ( -0.406)
0.365 0.116 0.005 - 0.635 0.134 0.007 CL -0.302 CF -0.430


8. Rollout 10/3 Eq.: -0.475 ( -0.451)
0.340 0.116 0.007 - 0.660 0.136 0.007 CL -0.369 CF -0.475




////////////////////////////////////////////21//////////////////////////////////////////

1. Cubeful 4-ply 24/23 7/1* Eq.: -0.508
0.397 0.191 0.005 - 0.603 0.162 0.015

2. Cubeful 4-ply 24/23 10/4 Eq.: -0.585 ( -0.077)
0.368 0.117 0.004 - 0.632 0.131 0.006

3. Cubeful 4-ply 10/4 6/5 Eq.: -0.626 ( -0.118)
0.371 0.156 0.006 - 0.629 0.150 0.009

4. Cubeful 4-ply 7/1* 6/5 Eq.: -0.688 ( -0.180)
0.393 0.208 0.006 - 0.607 0.201 0.019

5. Cubeful 4-ply 10/9 7/1* Eq.: -0.700 ( -0.192)
0.361 0.158 0.004 - 0.639 0.154 0.011

6. Cubeful 4-ply 7/6 7/1* Eq.: -0.716 ( -0.208)
0.350 0.138 0.003 - 0.650 0.140 0.009

7. Cubeful 4-ply 10/3 Eq.: -0.784 ( -0.276)
0.338 0.109 0.004 - 0.662 0.135 0.006

8. Cubeful 4-ply 7/1* 2/1 Eq.: -0.815 ( -0.307)
0.347 0.155 0.003 - 0.653 0.161 0.012



======================

1. Rollout 24/23 7/1* Eq.: -0.412
0.410 0.208 0.022 - 0.590 0.167 0.039 CL -0.323 CF -0.412


2. Rollout 7/1* 6/5 Eq.: -0.519 ( -0.108)
0.408 0.225 0.019 - 0.592 0.195 0.072 CL -0.363 CF -0.519


3. Rollout 24/23 10/4 Eq.: -0.572 ( -0.160)
0.377 0.146 0.016 - 0.623 0.143 0.016 CL -0.409 CF -0.572


4. Rollout 10/4 6/5 Eq.: -0.598 ( -0.186)
0.380 0.181 0.019 - 0.620 0.163 0.033 CL -0.407 CF -0.598


5. Rollout 7/6 7/1* Eq.: -0.607 ( -0.195)
0.366 0.162 0.014 - 0.634 0.144 0.020 CL -0.409 CF -0.607


6. Rollout 10/9 7/1* Eq.: -0.610 ( -0.198)
0.377 0.178 0.016 - 0.623 0.160 0.035 CL -0.403 CF -0.610


7. Rollout 10/3 Eq.: -0.731 ( -0.319)
0.354 0.141 0.015 - 0.646 0.148 0.017 CL -0.465 CF -0.731