3rd roll blunders against XG

I have owned XG for some time but never actually played against it.  That is, until about a couple weeks ago.  An anonomous friend and I played a money session as a consulting team.  It was a fun learning experience.  We talked about the plays, strategies, tactics, etc. and reviewed the games (and our errors) immediately afterword.

Based on that experience, I started a few days ago playing some money sessions by myself against the computer.  I play about 10 games (which goes really quick) then peruse the errors after.

Stick has recommended keeping a working file of blunders based on these games, and Robertie recommends categorizing your errors and printing them out - maintaining a working binder of errors.

All good advice, but I am not quite ready to go that extreme yet.

Here are some 3rd roll errors I have in recent sessions against XG.

***************
32 to play.  63S-52S-32??

is eXtremeGammon score: 1 pip: 160

Unlimited Game Jacoby Beaver

pip: 158 score: 6 is Bill $$

XGID=-a-a--E-C-A-dD---dAe----A-:0:0:1:32:6:1:3:0:10

to play 32

1.	XG Roller++	18/16 13/10	eq: +0.093
	Player: Opponent: 52.93% (G:11.67% B:0.43%) 47.07% (G:12.20% B:0.40%)
2.	XG Roller++	18/13	eq: -0.022 (-0.115)
	Player: Opponent: 49.64% (G:11.02% B:0.38%) 50.36% (G:12.51% B:0.42%)
3.	4-ply	6/3* 3/1*	eq: +0.056 (-0.037)
	Player: Opponent: 51.40% (G:13.63% B:0.39%) 48.60% (G:12.48% B:0.55%)

eXtreme Gammon Version: 2.02

I moved 18/16 running a man to the midpoint.

Better was 18/16, 13/10.

My play leaves 7's and 9's to hit.  That's 11 shots, though XG may forego the hit on 33.  Let's call it 10 shots.

The other play leaves 13 shots, but 22 44 and 31 are good shots anyway so let's call it 8 shots.  So with some sort of duplication at work, the direct shot costs less than the indirect shots.

And, of course, the bot's play makes a point.  Making a point is always good in the early game, no matter where it is.

****************
52 to play.  43Z-52H-52??

is eXtremeGammon score: 3 pip: 160

Unlimited Game Jacoby Beaver

pip: 164 score: 10 is Bill $$

XGID=-b----E-CA--dD---d-d-a--AA:0:0:1:52:10:3:3:0:10

to play 52

1.	XG Roller++	Bar/23 13/8	eq: -0.117
	Player: Opponent: 47.20% (G:13.34% B:0.63%) 52.80% (G:15.86% B:0.71%)
2.	XG Roller++	Bar/20 13/11	eq: -0.118 (-0.001)
	Player: Opponent: 47.50% (G:13.00% B:0.62%) 52.50% (G:15.53% B:0.90%)
3.	XG Roller++	Bar/20 24/22	eq: -0.139 (-0.022)
	Player: Opponent: 46.84% (G:11.77% B:0.55%) 53.16% (G:14.92% B:0.66%)
4.	XG Roller++	Bar/20 6/4	eq: -0.150 (-0.033)
	Player: Opponent: 47.05% (G:12.46% B:0.60%) 52.95% (G:16.89% B:1.02%)
5.	Book1	Bar/18	eq: -0.208 (-0.091)
	Player: Opponent: 45.62% (G:11.29% B:0.52%) 54.38% (G:17.42% B:0.75%)
1 Generated by GameSite 2000, Ltd on 2/26/2011 using eXtreme Gammon 2.00 Analyzed in XG Roller++

eXtreme Gammon Version: 2.02

I played Bar/18.  This is a terrible blunder.  I place my checker on a point he wants to make and diversiy his numbers.  2's and 4's cover while 1's and 6's hit.  Some numbers hit and cover.  Too much, and why?

Two plays are better.

One is the "normal" looking Bar/22, 13/8.  This doesn't do much except stay out of harm's way but remaining on the deep and ace duece points.  13/8 isn't great since the midpoint is already unstacked but once you enter on the duece what other five is there?  Well, there is my ridiculous Bar/21/18 but let's forget I did that!!

The other is the tactically oriented Bar/20, 13/11.  This places your checkers where you want 'em.  It is a bit blotty but the blots in my outfield are sort of a mirage.  These guys are immune for one roll since any indirect hit by XG gives me fours to hit back from the bar and fives to anchor and perhaps combo two's as well to hit back in my outfield.  So barring a joker dance these guys are really safe this turn.  Staying on the five point is a bit risky but the blot on his four point mutes the danger somewhat.  There are only a handful of hit and cover numbers.  Barring that I should get an opportunity to make a good anchor next turn or at least make an offensive point.

*************
21 to play from the air.  64R-52H-21??

is eXtremeGammon score: 3 pip: 160

Unlimited Game Jacoby Beaver

pip: 168 score: 11 is Bill $$

XGID=-b----E-C---cEa--d-e----AA:0:0:1:21:11:3:3:0:10

to play 21

1.	XG Roller++	Bar/24 13/11	eq: -0.176
	Player: Opponent: 45.97% (G:12.45% B:0.52%) 54.03% (G:16.46% B:0.94%)
2.	XG Roller++	Bar/22	eq: -0.233 (-0.057)
	Player: Opponent: 44.62% (G:10.81% B:0.43%) 55.38% (G:16.62% B:0.66%)
3.	4-ply	Bar/23 6/5	eq: -0.185 (-0.008)
	Player: Opponent: 45.91% (G:11.45% B:0.46%) 54.09% (G:17.09% B:0.84%)

eXtreme Gammon Version: 2.02

I played Bar/22, inching up to influence the outfield and splitting to try and make an anchor.

Better was Bar/24, 13/11.  

I am not in urgent need of an anchor here.  He has made no points yet and in fact has a stacky position.  He would love to unload his stacks upon my pretty little head. Better to fight a stacky attacky position with an anchor than to 'spread the legs.' 

Besides those defensive points, Bar/24, 13/11 also unstacks my midpoint to an effective spot to develop my forward position.  The 11 point is only vulnerable to 64 (which as a bonus 64 is duplicated on his side of the board).  meanwhile the 11 point builder aims at both the bar and the 5 point. 

This play seems pretty clear to me now.  Hopefully I will get it right in the future.

*****************
53 to play.  62S-22A-53??

is eXtremeGammon score: 2 pip: 159

Unlimited Game Jacoby Beaver

pip: 159 score: 3 is Bill $$

XGID=-b----E-C--AcDb--cAc-b--A-:0:0:1:53:3:2:3:0:10

to play 53

1.	XG Roller++	18/10	eq: -0.251
	Player: Opponent: 43.98% (G:11.06% B:0.47%) 56.02% (G:16.16% B:0.67%)
2.	XG Roller++	18/13 11/8	eq: -0.282 (-0.031)
	Player: Opponent: 43.63% (G:10.25% B:0.49%) 56.37% (G:16.97% B:0.51%)
3.	XG Roller++	8/3 6/3	eq: -0.316 (-0.065)
	Player: Opponent: 43.05% (G:12.45% B:0.75%) 56.95% (G:20.21% B:1.07%)

eXtreme Gammon Version: 2.02

I made a point 8/3, 6/3.  While it would be nice to make the bar point this just seems too unlikely to work.  I am staring down a triple shot and standing on a point he would actually like to make.  At first glance this looks like a distraction play but XG already has the 4 point made so building either the bar or the 5 point starts to fill in a budding prime.  It looks in most variations I get and if I don't perform from the bar I am in big trouble already.

Better was 18/13, 11/8.  I suppose this way I hope to escape one man.  If I am not hit, then I am good shape to make a point somewhere next turn with a playable game.  There is also some duplication at work - 63 64 are both good shots on his side of the board - but I don't think this is the main reason.

Also not the wimp inspired 18/13, 11/8 is a reasonable if not entirely correct play.  This escapes the back man for sure by leaving no blots but at the cost of a stacked position.  XG is building structre quickly so I will need to roll well from here for this to work but note it is still superior to my play, which 'leads with the chin.'

robotkiller

Below are selected errors from the opening game of a 7 point online match against robotkiller.

**********

I am on roll.  Cube action?

is robotkiller score: 0 pip: 187

7 point match

pip: 155 score: 0 is Chutzpah

XGID=-b-Ba-CaC---dE---c-dA-A---:0:0:1:00:0:0:0:7:10

on roll, cube action?

Analyzed in XG Roller++	No double	Double/Take
Player Winning Chances:	60.64% (G:24.25% B:2.36%)	60.74% (G:24.21% B:2.39%)
Opponent Winning Chances:	39.36% (G:7.69% B:0.29%)	39.26% (G:7.60% B:0.29%)
Cubeless Equities	+0.406	+0.842
Cubeful Equities
No double:	+0.582
Double/Take:	+0.519 (-0.063)
Double/Pass:	+1.000 (+0.418)
Best Cube action: No double / Take
Percentage of wrong pass needed to make the double decision right: 11.6%

eXtreme Gammon Version: 2.02, MET: Kazaross XG2

I am up in the race, have him outboarded and am shooting at two blots with the potential to blitz.

I doubled and robotkiller took.  And yet the proper cube action is No double.  What gives?

My guess is that my extra home board point, the 3 point, is a bit too deep.  The priming threat is not as strong so I have mostly the blitz threat only.  However, robot is already anchored so this threat is diminished.

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

I altered the position a bit so that I have the 4 point instead of the 3 point and now the position is borderline cube.  I have more of a two-way game now, where I have potential to semi-blitz or prime.

is Player 2 score: 0 pip: 186

7 point match

pip: 157 score: 0 is Player 1

XGID=-b--BaCaC---dE---c-dA-A---:0:0:1:00:0:0:0:7:10

on roll, cube action?

Analyzed in XG Roller++	No double	Double/Take
Player Winning Chances:	62.98% (G:23.63% B:2.24%)	62.99% (G:23.73% B:2.25%)
Opponent Winning Chances:	37.02% (G:6.98% B:0.24%)	37.01% (G:6.97% B:0.25%)
Cubeless Equities	+0.452	+0.934
Cubeful Equities
No double:	+0.637
Double/Take:	+0.634 (-0.003)
Double/Pass:	+1.000 (+0.363)
Best Cube action: No double / Take
Percentage of wrong pass needed to make the double decision right: 0.8%

eXtreme Gammon Version: 2.02, MET: Kazaross XG2

**********************
Very next roll.  How to play 32?

is robotkiller score: 0 pip: 187

7 point match

pip: 155 score: 0 is Chutzpah

XGID=-b-Ba-CaC---dE---c-dA-A---:1:-1:1:32:0:0:0:7:10

to play 32

1.	XG Roller++	22/20 13/10	eq: +0.146
	Player: Opponent: 58.59% (G:18.93% B:1.04%) 41.41% (G:7.49% B:0.23%)
2.	XG Roller++	13/10 6/4*	eq: +0.073 (-0.074)
	Player: Opponent: 55.86% (G:20.07% B:1.63%) 44.14% (G:9.80% B:0.40%)
3.	4-ply	20/15	eq: +0.066 (-0.081)
	Player: Opponent: 56.55% (G:18.24% B:1.10%) 43.45% (G:9.92% B:0.35%)

eXtreme Gammon Version: 2.02, MET: Kazaross XG2

I pounced, like I always do.  13/10, 6/4*.  But I am overlooking that I actually have a three-way game here.  There are the semi-blitz and prime plans as I already mentioned.  But there is also the simple racing plan.

And it looks this dud of a roll best caters to a race.  22/02, 13/10 anchors up, duplicated 3's and 6's and preserves the most of my racing lead that I can.  A long game is ahead and while it would be nice to have the cube back at least I am still a solid favorite.

************
Later in the same game and I have 64 to play.

is robotkiller score: 0 pip: 175

7 point match

pip: 122 score: 0 is Chutzpah

XGID=-aBBBbBb-D--b-A-ab-c-Bb---:1:-1:1:64:0:0:0:7:10

to play 64

1.	XG Roller++	14/4	eq: +0.140
	Player: Opponent: 56.93% (G:24.42% B:0.59%) 43.07% (G:8.45% B:0.30%)
2.	XG Roller++	14/10 9/3	eq: +0.087 (-0.053)
	Player: Opponent: 54.91% (G:24.44% B:0.76%) 45.09% (G:9.10% B:0.33%)
3.	XG Roller++	21/15 14/10	eq: +0.030 (-0.110)
	Player: Opponent: 53.91% (G:22.73% B:1.01%) 46.09% (G:10.48% B:0.49%)

eXtreme Gammon Version: 2.02, MET: Kazaross XG2

A case of 'long think, wrong think.'  I made the 'creative' play 21/15, 14/10 making a play for the outfield and leaving three blots in jeopardy, but at a time when robot only has a two point board.  Still, this is just wrong.  This is unlikely to work and could turn into a disaster.  Best was to simply safety one man with 14/4 and await further developments.

***********

One more from this game.  I got hit in the bearoff and am now facing a recube.  Take or Drop?

is robotkiller score: 0 pip: 109

7 point match

pip: 44 score: 0 is Chutzpah

XGID=-GBC-a----a----b-b-bbbbaA-:1:-1:-1:00:0:0:0:7:10

on roll, cube action?

Analyzed in XG Roller+	No redouble	Redouble/Take
Player Winning Chances:	72.44% (G:0.00% B:0.00%)	72.25% (G:0.00% B:0.00%)
Opponent Winning Chances:	27.56% (G:7.09% B:0.05%)	27.75% (G:7.79% B:0.05%)
Cubeless Equities	+0.372	+0.776
Cubeful Equities
No redouble:	+0.696
Redouble/Take:	+0.648 (-0.048)
Redouble/Pass:	+1.000 (+0.304)
Best Cube action: No redouble / Take
Percentage of wrong pass needed to make the double decision right: 12.0%

eXtreme Gammon Version: 2.02, MET: Kazaross XG2

I dropped. Two off is not a lot and this position didn't look promising.  And yet the recube is even too early and dropping a heart attack triple whopper!!

To see my chances in action I swapped sides and played some games agasint the computer.

1: Won 8 points.  Hit loose with an ace.  Closed him out but XG bounced in immediately and got an 8 cube in, which I ended up winning anyway.

2: Won 2 points.  Covered 2 point immediately.  Hit loose on ace and closed him out.

3: Won 2 points.  Rolled mega joker 33 making full prime and rolled home the win.

4:  Won 2 points.  Covered 2 point immedately.  Then attacked on the ace point when it failed to escape.  Another easy win.

5:  Won 8 points.  Covered 2 point immediately.  Got hit with escaping six and had to stare down an 8 cube.  I got lucky and hit him.  Closed him out.  Got hit in the bearoff but luckily hit him a second time coming around to lock up the win.

6: Won 2 points.  Covered two point immediately.  Got hit with escapgin six but rolled a joker from the bar to enter and rehit.  Rolled home to another easy win.

7:  Won 2 points.  Hit loose with ace.  Covered ace point.  Misplayed the close out with open duece point but managed to win anyway.

8:  Won 2 points.  Covered 2 point first roll.  XG rolled an escaping and hitting joker but I hit back from the bar and won anyway.

9: Won 2 points.  Covered 2 point right away.  XG rolled a six on second try to get in the outfield but I hit back and won.

10: Won 2 points.  Covered 2 point right away.  XG failed to roll a six for several turns.  I misplayed the outfield containment but eventually hit loose onthe ace point and won again anyway.

Wow!!  So I won all ten times.  What did I learn from this exercise?  While I won every time, I did see how I could lose.  I may not cover the two point in which case XG gets a free shot to hit a blot (not a game winner to be sure but it helps).  Mostly XG gets a couple chances (usually) to roll a six out.  That six out could also hit in which case I am under big pressure to perform else get an 8 cube.  Also XG could six out and I simply miss in which case I am also under big pressure.  Even after the duece is covered and I hit loose on the ace there are oddball variations where I can't close him out.  And of course, XG retains some equity even after being closed out - having borne off 2 checkers.

Another point to consider how hard/easy the checker plays are for the stronger side.  I managed to play ten games with only two sizable errors but I could easily see people making mistakes.  So there is some likely equity gain there.  On the other hand, if you take this four cube you need to prepared to send an agressive 8 cube - you could cost yourself equity by not rewhipping fast enough when things turn around.

Knightmoves22 (bonehead cubes)

A series of boneheaded cube decisions by me, from an online match against Knightmoves22.

First a checker error.  53 to play.

is Knightmoves22 score: 0 pip: 145

7 point match

pip: 136 score: 0 is Chutzpah

XGID=-BaBa-C-B--AbC---cce-A-A--:0:0:1:53:0:0:0:7:10

to play 53

1.	XG Roller++	21/16 11/8	eq: +0.092
	Player: Opponent: 52.12% (G:16.29% B:0.41%) 47.88% (G:13.65% B:0.53%)
2.	XG Roller++	23/15	eq: +0.056 (-0.036)
	Player: Opponent: 51.41% (G:14.94% B:0.39%) 48.59% (G:13.91% B:0.65%)
3.	XG Roller++	21/13	eq: +0.006 (-0.086)
	Player: Opponent: 49.43% (G:15.26% B:0.34%) 50.57% (G:12.82% B:0.49%)

eXtreme Gammon Version: 2.02, MET: Kazaross XG2

I ran the midpoint.  Safe, obvious.  Pick pu the dice.

To my suprise this is a whopper of an error.  I never saw a second play, and in fact there are two superior options to my "obvious" choice.

Best is 21/16, 11/8.  I guess the idea is to make him pay to hit the blot.  Hitting on his side of the board breaks his midpoint, ceding outfield control and also gains a few pips less in the race, and also doesn't allow him to simulatenously hit and escape.

Also good is 23/15, a play I would likely never consider.  I suppose the guy on the two point is the most difficult to get going and we are up in the race, so we can take some chanecs while he only has a 1-point board.  This is blotty but I have good connectivity.  All blots support each other by being less than six pips apart.

***************
I am on roll.  Cube action?

is Knightmoves22 score: 0 pip: 44

7 point match

pip: 39 score: 0 is Chutzpah

XGID=-CBCCAA------------c-dbb--:1:1:1:00:0:0:0:7:10

on roll, cube action?

Analyzed in XG Roller++	No redouble	Redouble/Take
Player Winning Chances:	67.61% (G:0.00% B:0.00%)	67.56% (G:0.00% B:0.00%)
Opponent Winning Chances:	32.39% (G:0.00% B:0.00%)	32.44% (G:0.00% B:0.00%)
Cubeless Equities	+0.352	+0.728
Cubeful Equities
No redouble:	+0.612
Redouble/Take:	+0.496 (-0.116)
Redouble/Pass:	+1.000 (+0.388)
Best Cube action: No redouble / Take
Percentage of wrong pass needed to make the double decision right: 18.7%

eXtreme Gammon Version: 2.02, MET: Kazaross XG2

I redoubled and Knightmoves22 took.

This was superficial thinking on my part.  I saw the pips as 39 to 44 lead, and figured as follows.  Using Trice, point of last take is 39 - 5 divided by 7 or 5.  I am up 5 pips so let's recube and let him worry about the take.

Again, this is too shallow an analysis.  I need to consider the relative EPC's of our repsective positions.  In other words, I need to make adjustments for distribution.  My position is sort of flat so let's add 10 pips there and also penalaive myself about 4 pips for extra men on the ace point.  This gives me an adjusted pip count of about 53.

Knightmoves22 has a flatish position - the gap on 5 point is bad but nobody on the ace is good, so let's just call these a wash and add 10 pips and call it a day.  Probably wrong but I don't claim to be good at this.  Anyway that gives Knightmoves an adjusted pip count of about 54.

Up one pip (53 to 54) in a medium length race is obviously no recube.  No redouble / Take.

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

I lead 3 away 6 away and Knightmoves doubles.  Take or Drop?

is Knightmoves22 score: 1 pip: 133

7 point match

pip: 141 score: 4 is Chutzpah

XGID=-a---DC-C---eC--Aa-bbbb-A-:0:0:-1:00:4:1:0:7:10

on roll, cube action?

Analyzed in XG Roller+	No double	Double/Take
Player Winning Chances:	68.93% (G:28.24% B:0.76%)	68.89% (G:28.56% B:0.70%)
Opponent Winning Chances:	31.07% (G:6.20% B:0.25%)	31.11% (G:6.37% B:0.27%)
Cubeless Equities	+0.595	+1.299
Cubeful Equities
No double:	+0.914 (-0.086)
Double/Take:	+1.231 (+0.231)
Double/Pass:	+1.000
Best Cube action: Double / Pass

eXtreme Gammon Version: 2.02, MET: Kazaross XG2

I took.  big time oops.

Let's look at Joe Sylvester's criteria first - Position, Pips, Threats.

I am outboarded, down in the race, and opponent is shooting at a loose blot.  I am down in all phases of the game, opponent has significant threats and to top it all off I get gammoned a lot.  Add it all up and it an easy drop.  Factor in the elevated gammon value at this score and you get insult to injury with this boneheaded take.

**********
I lead 3 away 4 away and am facing a recube for the match?  Take or Drop?

is Knightmoves22 score: 3 pip: 132

7 point match

pip: 142 score: 4 is Chutzpah

XGID=-a-BBBB-C---c-b--aBccAb--A:1:-1:-1:00:4:3:0:7:10

on roll, cube action?

Analyzed in XG Roller++	No redouble	Redouble/Take
Player Winning Chances:	56.82% (G:23.39% B:0.57%)	57.64% (G:22.17% B:0.61%)
Opponent Winning Chances:	43.18% (G:12.58% B:0.64%)	42.36% (G:12.42% B:0.62%)
Cubeless Equities	+0.476	+0.889
Cubeful Equities
No redouble:	+0.794 (-0.095)
Redouble/Take:	+0.889
Redouble/Pass:	+1.000 (+0.111)
Best Cube action: Redouble / Take

eXtreme Gammon Version: 2.02, MET: Kazaross XG2

I don't feel too bad about this one, despite the size of the error.  I knew the lost gammons didn't matter and that my takepoint was 40%, so the question is simply can I win 40% of the time?

OK so I misjudged the position but at least I had my bearings right.

The important features giving me good winning chances are:

• I have a very strong board
• Knightmoves still has a man trapped on my ace point. 
• Knightmoves only has a 3 point board - I have decent prospects of establishing an anchor somewhere in which case I have a solid game.
• Any hits from the bar from me are deadly - Knightmoves has to be careful in conducting this blitz.
• He only has nine men within direct attacking range.