Ali post 2

Here are some more positions from my match against Ali.


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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++	13/5	eq: -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* 21/15	eq: -0.343 (-0.072)
	Player: Opponent: 47.59% (G:12.51% B:0.72%) 52.41% (G:20.02% B:1.10%)
3.	3-ply	24/18 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.


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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 13/8	eq: -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-ply	13/11 13/8	eq: -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.

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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 13/11	eq: -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 10/8	eq: -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 22/20	eq: -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.

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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 13/10	eq: +0.066
	Player: Opponent: 53.53% (G:12.13% B:0.46%) 46.47% (G:10.74% B:0.26%)
2.	XG Roller++	16/8	eq: -0.041 (-0.106)
	Player: Opponent: 50.21% (G:11.26% B:0.40%) 49.79% (G:10.05% B:0.22%)
3.	3-ply	16/11 8/5	eq: -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.

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

Ali post 1

I was invited this year to particiapte in the Michigan versus Ohio challenge. Michigan won, and I was fortunate to earn top individual honors with a performance of 7-1. I recorded three of my matches and plan on looking at some of my mistakes here. Based on these three matches, I am forced to conclude my success was more a story of hot dice than strong play.

Several errors were the WTF variety, like me missing a hit or missing making a key point or reading the die wrong. How does that happen?

Otheres were outrageously bad cube decisions. All over the map too. Sometimes I am doubling crazy early, while other times I don't double at all, missing a clear double.

I also got into several backgames and played them all like a chump. I need to go back to square one when it comes to backgames. My thinking was completely wrong, leading me to make fundamental mistakes move after move after move after move. Needless to say, repeated checker play whoppers doesn't help your PR. The last two games against Ali were both backgames where I posted a 7 in one game and a 15 in the other!! Keep in mind these are long games, many moves, many decisions. These are the games to lower your PR since you get a big base of decisions to smooth out your blunders. And yet, disaster!! My overall PR this match was a humbling 7.8

What follows are errors from the first several games of my match against Ali. I intend on looking at the concluding backgames separately.


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Score is 7 away 7 away. 21 to play.

is Ali score: 0 pip: 147

7 point match

pip: 149 score: 0 is Bill

XGID=-a--a-EBB---bEa-ac-d-b--A-:0:0:1:21:0:0:0:7:10

to play 21

1.	XG Roller++	24/23 6/4*	eq: -0.235
	Player: Opponent: 46.03% (G:11.44% B:0.67%) 53.97% (G:19.94% B:0.67%)
2.	XG Roller++	7/5 6/5	eq: -0.235 (-0.001)
	Player: Opponent: 45.11% (G:12.07% B:0.62%) 54.89% (G:18.59% B:0.88%)
3.	XG Roller++	6/4* 4/3	eq: -0.247 (-0.013)
	Player: Opponent: 45.29% (G:10.91% B:0.56%) 54.71% (G:18.56% B:0.72%)
4.	XG Roller++	24/23 13/11	eq: -0.267 (-0.033)
	Player: Opponent: 45.09% (G:9.41% B:0.44%) 54.91% (G:18.55% B:0.52%)

eXtreme Gammon Version: 2.02, MET: Kazaross XG2

I moved 24/23, 13/11. With one man back to his two I figured I don't want to get hit here. And yet there are three better plays than mine, all of which expose myself to a doubleshot.

The computer likes 24/23, 6/4*, which unstacks, keeps the mini-prime and takes away half the roll.

I think I prefer 7/5, 6/5 but this is a dangerous lessson to learn. The 5-point is forever and I can understand the motivation to play that. On the other hand a doubleshot is a lot and it's probably rare that this can be right. Probably this is a special circumstance as both Ali's 6's and 3's are duplilacted a bit. In fact, all sixes are pretty good for Ali which either escape or make his 5 point. So the "cost" of getting hit on my bar point is not so bad. Similarly, Ali's 3's either make the advanced anchor or make his 5 point in addition to hitting me. So once again the cost isn't so bad.

The weird one to me is the computer likes 6/4*/3 over my play. I guess this is telling me I can't hang back and allow Ali to play his full roll. Something good is going to happen next time for him - either hit in the outfield, anchor, make an offensive point...I must slow him down seems to be the most important thing in this position.


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7 away 7 away . 31 to play.

is Ali score: 0 pip: 116

7 point match

pip: 155 score: 0 is Bill

XGID=--a-B-CBB---bCA-ab-cbbbB--:0:0:1:31:0:0:0:7:10

to play 31

1.	XG Roller++	14/11 6/5	eq: -0.362
	Player: Opponent: 43.49% (G:6.01% B:0.17%) 56.51% (G:24.44% B:1.50%)
2.	XG Roller++	14/10	eq: -0.408 (-0.046)
	Player: Opponent: 40.61% (G:5.81% B:0.16%) 59.39% (G:18.25% B:0.92%)
3.	3-ply	13/9	eq: -0.576 (-0.214)
	Player: Opponent: 38.50% (G:5.15% B:0.20%) 61.50% (G:23.36% B:1.50%)

my excuse for this was i thought the roll was 21 and played 14/11.  Ali corrected me that is was 31 and I simply moved 14/10 without thinking about the play.  I think I would have slotted if I saw the dice right the first time.

eXtreme Gammon Version: 2.02, MET: Kazaross XG2

This isn't an outrageous error but an example of me misreading the die. I thought the roll was 21 and moved 14/11. Ho hum. Then Ali pointed out the roll was 31 so I just moved my man another pip - resulting in the move 13/10.

If I had thought at all, I am sure I would have come up with the correct move 13/11, 6/5. I need to make the 5-point to win and slotting is the way to go about it before Ali can cube.

This is an example of careless play on my part. The lesson is to move the man back to the original position and look at the position anew.

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I trail 6 away 7 away, have already doubled, and have 62 to play.

is Ali score: 1 pip: 124

7 point match

pip: 141 score: 0 is Bill

XGID=---b-BDBBA--bB---b-cbBc-a-:1:-1:1:62:0:1:0:7:10

to play 62

1.	XG Roller++	13/11 13/7	eq: +0.061
	Player: Opponent: 57.43% (G:12.15% B:0.46%) 42.57% (G:10.62% B:0.23%)
2.	XG Roller++	13/7 9/7	eq: +0.038 (-0.022)
	Player: Opponent: 55.89% (G:12.62% B:0.56%) 44.11% (G:9.27% B:0.20%)
3.	XG Roller+	9/1	eq: +0.045 (-0.016)
	Player: Opponent: 55.80% (G:14.33% B:0.41%) 44.20% (G:10.12% B:0.24%)

eXtreme Gammon Version: 2.02, MET: Kazaross XG2

I played 13/7, 9/7. I figured I didn't want to let him hit and escape at the same time.

The computer likes 13/11, 13/7.

The number of shots are the same after either pay so that's not the issue.

I think the factors at play are ....

1) make him to pay to hit: even though he's escaping he is leaving the anchor. I may be able to attack that blot before he escapes the other man. With my play he uses aces to hit on the midpoint which is a small cost sure but not so bad as Ali will dominate the outfield.

2) I have return shots from the bar. If he hits me I may roll an ace right back.

3) He might miss! If he does miss than I retain the possibility of rolling a 2 (or boxes) to make the 9 point block. 53 would make the 4 point.


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Later in the same game. 43 to play.

is Ali score: 1 pip: 84

7 point match

pip: 112 score: 0 is Bill

XGID=aB---CCBBa----AA--Abc-cbc-:1:-1:1:43:0:1:0:7:10

to play 43

1.	XG Roller++	6/2 5/2	eq: +0.303
	Player: Opponent: 65.43% (G:17.48% B:0.41%) 34.57% (G:13.28% B:0.31%)
2.	XG Roller++	15/11 14/11	eq: +0.232 (-0.071)
	Player: Opponent: 62.23% (G:11.85% B:0.28%) 37.77% (G:5.23% B:0.06%)
3.	XG Roller++	18/14 15/12	eq: +0.231 (-0.072)
	Player: Opponent: 62.54% (G:11.82% B:0.32%) 37.46% (G:5.99% B:0.05%)

eXtreme Gammon Version: 2.02, MET: Kazaross XG2

First off my play was 18/14, 15/12. This cleans up a blot, duplicates threes to enter and hit and puts myself in a position to hit Ali's loose blot next turn if he rolls a dud. But this move gives him good sixes. 36 anchors while 26 or 46 escape a blot completely. Also, 43, 33, and 23 hit me from the bar - a disaster.

Another poor play is one I didn't even see. 15/11, 14/11 is probably the play I would have made had I seen it!! I set up a bunch of plays but didn't notice this one. It is very frustrating when that happens, and it has been happening a lot to me lately. I do listen to music but I don't think this is the reason. Perhaps Ali's slow play was a contributing factor. I'm not sure. I need to find a way to retain good concentration.

Anyway, this play looks appealing at first glance. The chief virtue of this play is it leaves no return shots. I also retain my backmost man to play defense with.

But neither of these plays make another point and that appears to be the most important feature of this position. Hence the computer play 6/2, 5/2. This jumps the number of dancing numbers from 9 to 16, a significant increase. And if Ali does dance, I have 5's and 6's to pick up a second blot next time. The risk is I leave Ali some jokers - 35 36 45 46 or 33 are slam dunk killers. Nine super-jokers weighed against 7 more dancing numbers seems like too much risk yet it's right. Why? Perhaps one explanation is if Ali does hit I come back in on his board 30% of the time. So the practical impact of those 9 jokers is a bit less, maybe closer to about 7 real hits. Maybe it's that the upside is really more than those 7 dancing numbers. First if he does dance, which is about 45% this is really bad as I will likely scoop up that second blot. And if Ali enters and doesn't hit, I am still positioned to scoop up that second blot. So just put your checkers where you want them assuming the opponent dances and cross your fingers. No fear!!

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Later in the same game. I am on roll, owning a four cube and trailing 6 away 7 away. Too good or cash?

is Ali score: 1 pip: 76

7 point match

pip: 96 score: 0 is Bill

XGID=aBB-BCC-------B--a-bcAcbc-:2:1:1:00:0:1:0:7:10

on roll, cube action?

Analyzed in XG Roller++	No redouble	Redouble/Take
Player Winning Chances:	85.21% (G:17.83% B:0.47%)	85.89% (G:13.43% B:0.32%)
Opponent Winning Chances:	14.79% (G:1.50% B:0.03%)	14.11% (G:1.33% B:0.03%)
Cubeless Equities	+0.882	+1.534
Cubeful Equities
No redouble:	+1.095
Redouble/Take:	+1.534 (+0.439)
Redouble/Pass:	+1.000 (-0.095)
Best Cube action: Too good to redouble / Pass
Percentage of wrong take needed to make the double decision right: 17.8%

eXtreme Gammon Version: 2.02, MET: Kazaross XG2

OK so we know Ali is not taking but should we double?

What has to happen for Ali to take? I miss and he enters. This happens roughly 70% times 30% or about 15%. I figured my gammon chances weren't too big so I should just bank the points.

And yet this a big error. I am way too good. What is going on?

It looks like on the bad scenario (I miss, he enters) I still have a strong recube. If I hit I am happy. If I don't hit and he dances I am happy. If I miss and he enters (the bad scenario) I am still happy since I can send a powerful recube anyway.

That all adds up to shut up and roll.

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Enough for one post. More to follow. Bill