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October 17, 2013

Ali - Backgame

Finally to the last game!! It's DMP and there are too many blunders too count.


42 to play.

is Ali

score: 6
pip: 95
                         
7 point match
                          pip: 226
score: 6

is Bill
XGID=-----ABAA--aaBB--abcbcbDB-:0:0:1:42:6:6:0:7:10
to play 42

1.XG Roller++8/4 7/5eq: -0.072
Player:
Opponent:
46.38% (G:1.53% B:0.07%)
53.62% (G:31.59% B:11.32%)
2.XG Roller++14/10 7/5eq: -0.094 (-0.022)
Player:
Opponent:
45.28% (G:1.42% B:0.07%)
54.72% (G:33.28% B:12.59%)
3.XG Roller+8/4 6/4eq: -0.071 (+0.001)
Player:
Opponent:
46.45% (G:1.18% B:0.04%)
53.55% (G:31.80% B:11.54%)
eXtreme Gammon Version: 2.02, MET: Kazaross XG2

Not a big mistake to start, but an instructive one. At least it would be instructive if I knew what the proper lesson was. I;m afraid I don't know what's up with this one.

I played 14/10, 7/5. Make the points in order and I don't care if I get hit.

But should I care? Timing is a major consideration and I should have enough here ... Does getting hit here help or hurt? It might help if I get hit and dance for a while. It might help if I get hit and recycle. It could hurt if I come in right away and never roll a six. I'd say it's not clear on the timing issue.

Probably the main factor is I already have six men back and that's enough!! The more men back, the more split my army becomes. After all, I want to have a good offense in place and this will be very difficult to assemble with seven men back! But this is just a guess on my part.

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

53 to play.

is Ali

score: 6
pip: 27
                         
7 point match
                          pip: 187
score: 6

is Bill
XGID=-----BBB-B-AA---A--c--cBB-:0:0:1:53:6:6:0:7:10
to play 53

1.XG Roller++16/13 11/6eq: -0.178
Player:
Opponent:
41.11% (G:0.00% B:0.00%)
58.89% (G:34.58% B:23.83%)
2.XG Roller++11/6 9/6eq: -0.181 (-0.004)
Player:
Opponent:
40.94% (G:0.00% B:0.00%)
59.06% (G:35.59% B:24.81%)
3.XG Roller++23/20 16/11eq: -0.276 (-0.099)
Player:
Opponent:
36.18% (G:0.00% B:0.00%)
63.82% (G:41.19% B:28.62%)
eXtreme Gammon Version: 2.02, MET: Kazaross XG2


The computer likes any play which keeps the double anchor. My preference would be for 16/8 which slots the next point in the prime but XG doesn't analyze this move.

I panicked and 23/20, 16/11. This abandons the double anchor but gives Ali 4's to play. He's down to six men and I am feeling the pressure to hit something. On principle my play makes "sense" to me but apparently my gut is just way off here.

Let's try to see how the numbers pay after splitting 23/20 compared to holding the anchors ....

65. Wash. Good roll either way.
64. +Split. Disaster for Ali if I split. Good roll if I hold anchors.
63. Wash. Good roll either way.
62. Wash. Disaster for Ali either way.
61. Wash. Disaster for Ali either way.
54. +Split. I get immediate shot on split. Roll is stuck is hold anchors.
53. Wash. Good roll either way.
52. Wash. I get double shot either way.
51. +Anchors. 6/5*/off if I split. 6/5/off good roll with the anchors but at least I am not in the air.
43. +Split. I get an immediate shot if I split. Plays safe if I hold anchors.
42. Wash. Plays safe for Ali either way.
41. +Anchors. Point on head if I split. Double shot if I hold anchor.
32. Wash. Double shot either way.
31. +Anchors. I get an almost double shot from bar if I split. Double shot at two different blots if I hold anchors.
21. +Anchors. If I split, pick/pass/score 3/2*/off. If hold anchor it plays safe but I keep the anchors and am on the ground.
66. Wash. Killer roll for Ali either way.
55. Wash. Doesn't play either way.
44. +Anchors. Superjoker if I spilt. Roll doesn't play if I hold anchor.
33. Wash. Great roll either way.
22. +Split. A good roll but at least I get a shot by splitting. Awesome roll for Ali if I hold anchor.
11. +Anchors. A pretty good roll either way as I get a shot but I think having the anchor is better long-term.

So tallying up ...

Anchors win on 4 rolls plus double 4 and double 1 or 10 rolls total.
Splitting wins on 3 rolls plus double 2 or 7 rolls total.


I guess that's the reason. Anchoring wins on net 3 rolls and eliminates 44 as a superjoker.

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

53 to play.


is Ali

score: 6
pip: 36
                         
7 point match
                          pip: 171
score: 6

is Bill
XGID=--a--BBB-B-BA-A----a-AbAaA:0:0:1:53:6:6:0:7:10
to play 53

1.XG Roller+Bar/20 5/2* eq: +0.082
Player:
Opponent:
54.10% (G:0.00% B:0.00%)
45.90% (G:27.45% B:11.53%)
2.XG Roller+Bar/20 9/6eq: +0.016 (-0.066)
Player:
Opponent:
50.82% (G:0.00% B:0.00%)
49.18% (G:20.62% B:6.99%)
3.XG Roller+Bar/20 12/9eq: +0.011 (-0.071)
Player:
Opponent:
50.56% (G:0.00% B:0.00%)
49.44% (G:21.83% B:6.61%)
eXtreme Gammon Version: 2.02, MET: Kazaross XG2

One of the few that I got right. I am desperate to get the second checker so Bar/20, 5/2* is called for.


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

41 to play.


is Ali

score: 6
pip: 59
                         
7 point match
                          pip: 199
score: 6

is Bill
XGID=-aa--ABB-B-AA-A----aAAbAAA:0:0:1:41:6:6:0:7:10
to play 41

1.XG Roller++Bar/24 9/5eq: -0.096
Player:
Opponent:
45.20% (G:0.00% B:0.00%)
54.80% (G:28.63% B:14.67%)
2.XG Roller++Bar/21 20/19* eq: -0.412 (-0.316)
Player:
Opponent:
29.39% (G:0.00% B:0.00%)
70.61% (G:46.34% B:24.81%)
3.3-plyBar/24 23/19* eq: -0.053 (+0.043)
Player:
Opponent:
47.36% (G:0.00% B:0.00%)
52.64% (G:37.31% B:17.67%)
eXtreme Gammon Version: 2.02, MET: Kazaross XG2


This is where I blew the game. I have actually studied these positions before and "knew" the right answer but I couldn't resist the forbidden fruit when push came to shove in the heat of a real game.

The correct strategy for this game is as follows:

I need to hit the first checker to have any chance of winning.

I also want to hit a second checker. Why? Because Ali already has 10 checkers off. If I manage to close Ali out with a single checker captured I will still be an underdog.

After I hit the second checker I absolutely do not want to hit the third man!! This is fundamental. The correct strategy is to hit two men and close out two men. If Ali anchors, then I simply break the prime, let Ali jump out and then proceed to close him out and scoop up the second man. Simple!!


Again I knew this yet went down the wrong path anyway. I really made only one conceptual mistake but it translates into checker play whopper almost every move.

The problem with hitting the third man is that once Ali anchors it is very difficult to force him to break the anchor. He can always keep throwing the third man around the board and not really care if I hit it or not. (Of course I shouldn't hit it at all).

So the best play is simply Bar/24, 9/5, This ignores the third man while remaking the key 5-point. Now I can concentrate on coaxing Ali's blots out to the midfield where I can eventually pick them up and close them out.

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

42 to play.

is Ali

score: 6
pip: 71
                         
7 point match
                          pip: 201
score: 6

is Bill
XGID=-a--aaBB-B-BA-A-----ABbAA-:0:0:1:42:6:6:0:7:10
to play 42

1.XG Roller++14/10 12/10eq: -0.078
Player:
Opponent:
46.11% (G:0.00% B:0.00%)
53.89% (G:19.31% B:5.53%)
2.XG Roller++9/5* 7/5eq: -0.271 (-0.193)
Player:
Opponent:
36.44% (G:0.00% B:0.00%)
63.56% (G:40.92% B:21.95%)
3.3-ply23/21 9/5* eq: +0.173 (+0.250)
Player:
Opponent:
58.63% (G:0.00% B:0.00%)
41.37% (G:33.33% B:19.64%)

eXtreme Gammon Version: 2.02, MET: Kazaross XG2



I made the "auto" play of 9/5*, 7/5 remaking the 5 point. What could be more logical?


This is another example of the wrong strategy. Again I want to force Ali out and around so I can focus on two blots only.


*******

51 to play.


is Ali

score: 6
pip: 67
                         
7 point match
                          pip: 213
score: 6

is Bill
XGID=---aaBBa-A-BA-A-----ABbAAA:0:0:1:51:6:6:0:7:10
to play 51

1.XG Roller++Bar/24 14/9eq: -0.323
Player:
Opponent:
33.85% (G:0.00% B:0.00%)
66.15% (G:39.63% B:19.65%)
2.XG Roller++Bar/24 12/7* eq: -0.484 (-0.161)
Player:
Opponent:
25.81% (G:0.00% B:0.00%)
74.19% (G:54.37% B:33.14%)
3.XG Roller++Bar/19eq: -0.552 (-0.229)
Player:
Opponent:
22.42% (G:0.00% B:0.00%)
77.58% (G:57.23% B:32.41%)

eXtreme Gammon Version: 2.02, MET: Kazaross XG2



I won't show every position but here is the theme in action again. The computer likes Bar/24, 14/9 ignoring the third man and starting to build a block against the remaining back two men.

I of course hit with Bar/24, 12/7*

***********

22 to play


is Ali

score: 6
pip: 70
                         
7 point match
                          pip: 181
score: 6

is Bill
XGID=---abCCA-B----A---A-A-bAB-:0:0:1:22:6:6:0:7:10
to play 22

1.XG Roller++23/21 14/12 9/7(2)eq: +0.294
Player:
Opponent:
64.72% (G:0.00% B:0.00%)
35.28% (G:10.92% B:3.78%)
2.XG Roller++14/12 9/7 9/5eq: +0.265 (-0.029)
Player:
Opponent:
63.25% (G:0.00% B:0.00%)
36.75% (G:12.45% B:4.44%)
3.XG Roller++18/14 9/7 5/3* eq: +0.100 (-0.194)
Player:
Opponent:
55.00% (G:0.00% B:0.00%)
45.00% (G:16.43% B:5.93%)

eXtreme Gammon Version: 2.02, MET: Kazaross XG2


One more with the same theme.

I made the bar, moved in the outfield 18/14 and hit loose 5/3*

The right idea is to make the bar 9/7 and any other deuces are OK. Don't hit!! Wait for him to break the anchor so you can focus on closing out two blots!!

**********

63 to play.

is Ali

score: 6
pip: 68
                         
7 point match
                          pip: 165
score: 6

is Bill
XGID=----cBCCB--A--------AAaaB-:0:0:1:63:6:6:0:7:10
to play 63

1.XG Roller++20/17 11/5eq: +0.414
Player:
Opponent:
70.71% (G:0.00% B:0.00%)
29.29% (G:6.89% B:1.88%)
2.XG Roller++20/14 11/8eq: +0.410 (-0.004)
Player:
Opponent:
70.49% (G:0.00% B:0.00%)
29.51% (G:6.67% B:1.85%)
3.XG Roller++21/15 20/17eq: +0.374 (-0.040)
Player:
Opponent:
68.68% (G:0.00% B:0.00%)
31.32% (G:7.57% B:2.07%)

eXtreme Gammon Version: 2.02, MET: Kazaross XG2



Actually I don't really care about the right play here. I want to focus on the winning percentage. I am about 70/30 to win after the best play. Pretty decent but I had closed two men out and Ali having 10 men off I would be in the low to mid 80's to win. a big difference!!



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