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October 5, 2013

Ali post 2

Here are some more positions from my match against Ali.


*************

I lead 3 away 6 away. 62 to play.

is Ali

score: 1
pip: 138
                         
7 point match
                          pip: 158
score: 4

is Bill
XGID=-b---AE-C---bD---c-e-abAA-:0:0:1:62:4:1:0:7:10
to play 62

1.XG Roller++13/5eq: -0.270
Player:
Opponent:
48.90% (G:14.58% B:0.74%)
51.10% (G:19.67% B:0.68%)
2.XG Roller++23/21* 21/15eq: -0.343 (-0.072)
Player:
Opponent:
47.59% (G:12.51% B:0.72%)
52.41% (G:20.02% B:1.10%)
3.3-ply24/18 23/21* eq: -0.387 (-0.117)
Player:
Opponent:
46.10% (G:11.36% B:0.64%)
53.90% (G:21.11% B:0.95%)
eXtreme Gammon Version: 2.02, MET: Kazaross XG2


OK this one is superobvious. Make the 5-point.

And yet I didn't do that. I don't really have an explanation for this. I post this position because I made the same error again recently. The best I can come up with is that I am ignoring my first instincts and outthinking myself.


************************

I lead 3 away 5 away and have 52 to play.


is Ali

score: 2
pip: 153
                         
7 point match
                          pip: 159
score: 4

is Bill
XGID=-a-Ba-D-B---dE---b-eb---B-:0:0:1:52:4:2:0:7:10
to play 52

1.XG Roller++24/22 13/8eq: -0.383
Player:
Opponent:
43.75% (G:10.89% B:0.46%)
56.25% (G:18.03% B:0.58%)
2.XG Roller++13/8 6/4* eq: -0.418 (-0.035)
Player:
Opponent:
43.53% (G:12.30% B:0.54%)
56.47% (G:18.58% B:1.07%)
3.3-ply13/11 13/8eq: -0.495 (-0.112)
Player:
Opponent:
40.73% (G:10.27% B:0.37%)
59.27% (G:17.93% B:1.00%)
eXtreme Gammon Version: 2.02, MET: Kazaross XG2

I attacked with 13/8, 6/4*

Better was 13/8, 24/22 and I don't really get why. I played around with the position a bit and the best I can come up with is Ali's ownership of the 5-point. Even though his builders are not ideal, the 5-point orients Ali towards a prming stucture rather than an attacking structure. Therefore, I should split for an anchor rather than try to attack. Give Ali the 4-point instead of the 5-point instead of the 5-point and now attacking with 13/8, 6/4* is correct.

*************

I lead 3 away 4 away and have 42 to play.

is Ali

score: 3
pip: 149
                         
7 point match
                          pip: 174
score: 4

is Bill
XGID=---b-BC-B-A-bDa--cbe-AA--A:0:0:1:42:4:3:0:7:10
to play 42

1.XG Roller++Bar/21 13/11eq: -0.059
Player:
Opponent:
51.34% (G:12.40% B:0.47%)
48.66% (G:12.63% B:0.46%)
2.XG Roller++Bar/21 10/8eq: -0.100 (-0.041)
Player:
Opponent:
49.71% (G:11.63% B:0.41%)
50.29% (G:11.71% B:0.38%)
3.XG Roller+Bar/21 22/20eq: -0.083 (-0.024)
Player:
Opponent:
50.52% (G:11.94% B:0.44%)
49.48% (G:12.23% B:0.40%)
eXtreme Gammon Version: 2.02, MET: Kazaross XG2

I played Bar/21, 10/8 tidying up the outfield.

Better was Bar/21, 13/11.

I am down in the race, have an anchor and Ali only has a one point board. The cost of getting hit is small. On the other hand, leaving the outfield double-blotted has some upside if missed. I have numbers working to make the 9, bar or 4 points. So tactically this makes sense, the risk versus reward angle. And strategically makes sense too. I want to keep my checkers in front of his anchor and strive to make blokcing points in front of him.

******************

Same game. 53 to play.

is Ali

score: 3
pip: 135
                         
7 point match
                          pip: 162
score: 4

is Bill
XGID=---b-BC-C---bD--AbbdbB--a-:0:0:1:53:4:3:0:7:10
to play 53

1.XG Roller++16/11 13/10eq: +0.066
Player:
Opponent:
53.53% (G:12.13% B:0.46%)
46.47% (G:10.74% B:0.26%)
2.XG Roller++16/8eq: -0.041 (-0.106)
Player:
Opponent:
50.21% (G:11.26% B:0.40%)
49.79% (G:10.05% B:0.22%)
3.3-ply16/11 8/5eq: -0.018 (-0.083)
Player:
Opponent:
51.20% (G:11.26% B:0.31%)
48.80% (G:10.23% B:0.24%)
eXtreme Gammon Version: 2.02, MET: Kazaross XG2

Same theme as last problem but the size of my error is larger.

I moved 16/8, nice and neat this roll but doesn't diversify rolls to make a blocking point next time.

Better was 16/11, 13/10 giving me builder distribution to make a blocking point next time. And the cost of getting hit is lessened by the return shots at his ace point blot.

Please don't overemphasize the ace point blot. If you clean up Ali's blot by making it a 5-point spare ... the blotty 16/11, 13/10 is still correct by a large margin! I would be exposed to 61, 62, 43 and 44. But 44 is a great roll anyway so that doesn't really count. So six numbers. Ali only has a 2-point board so I still get many return shots on a hit - lessening the impact. Also the game isn't even over if Ali hits and I don't hit back.

***************

Next time I will have to bite the bullet and look at these brutal backgames.

2 comments:

  1. Interesting positions as always! For the second position, I believe that the trouble with hitting is that getting sent back is costly when the race is close and you have the weaker board. Downgrading Ali's 5pt to the 4pt reduces the cost of getting hit back and so makes 6/4* more attractive.

    ReplyDelete
  2. Nice to hear from you Tim. Glad you are still around. On position two I like your explanation. Even though we both have two points board, Ali's is the better board. What a simple yet elegant observation that I totally overlooked. I am going to try and keep that concept in mind going forward.

    ReplyDelete