Game 1 - UKBGF is always a contender for best play Player: Opponent: 34.51% (G:4.71% B:0.16%) 65.49%...
Transcript of Game 1 - UKBGF is always a contender for best play Player: Opponent: 34.51% (G:4.71% B:0.16%) 65.49%...
Game 1
11 point match, Score is robin swaffield: 0, andy darby: 0
31: 8/5 6/5
This article is aimed at the improving player so a few words of explanation of the numbers that
accompany each roll in the analysis to follow might be apposite. The move description should be
obvious after a moment’s thought. The % figures by each move are respectively wins, gammons
and backgammons.
For example, 70.00% (G:30.00% B:5.00%) means that a player will win 70% of the remaining games, of
those 40% will be single wins, 25% will be gammons and 5% backgammons.
The equity (eq) after each move is a valuation of the position from the standpoint of the player
who has just made the move. (The opponent’s equity in the same position would be the same
number but the opposite sign).
An equity of 1.00 is a sure-fire victory (with no gammons). An equity of over 1 is possible when
you are a huge favourite and gammons are available. An equity of 0.00 is even-stevens whilst a
75-25% favourite (with no gammons) would give an equity of 0.500
The moves for each dice roll are shown in order of strength, with a tick corresponding to the play
made by Robin or Andy and the XG symbol evident if the bot disagrees with their choice. By each
non-best move is the difference (in equity) between it and the best. It is convention to call a
move with a greater than twenty millipoints (0.020) drop in equity an error and, if greater than
80 millipoints (0.080) a blunder.
If there are no sensible alternatives (or if the choice in plays is not worthy of comment) then I
have just listed the one move, otherwise you will see a selection of possible moves.
That’s enough waffle from me. Let’s get to the game.
XGID=-b----E-C---eE---c-e----B-:0:0:-1:31:0:0:0:11:10 Pip=167-167
1. Book1 8/5 6/5 eq: +0.236
Player: Opponent:
55.30% (G:16.29% B:0.69%) 44.70% (G:11.19% B:0.47%)
21: 24/23 13/11
XGID=-b----E-C---eE---b-db---B-:0:0:1:21:0:0:0:11:10 Pip=167-163
1. 4-ply 24/23 13/11 eq: -0.344
Player: Opponent:
41.96% (G:10.30% B:0.41%) 58.04% (G:17.89% B:0.85%)
65: 24/13
This is the standard response. The top players know the opening replies and to learn them, and
more importantly to understand them is an exercise worth spending the time and effort doing.
http://www.extremegammon.com/Openingbook.aspx is worth a look. To get a response wrong
will not usually result in a big enough equity difference to be officially classed as an error
according to XG. But bear in mind that half of all the backgammon games you play will require
you to make an opening move response and you can imagine how these little mistakes will add
up.
Useless fact: the worst possible start in backgammon is 31 followed by a 54.
XGID=-b----E-C--AeD---b-db--AA-:0:0:-1:65:0:0:0:11:10 Pip=164-163
1. XG Roller++ 24/18 13/8 eq: +0.331
Player: Opponent:
57.58% (G:16.87% B:0.81%) 42.42% (G:10.38% B:0.38%)
2. XG Roller++ 24/13 eq: +0.323 (-0.008)
Player: Opponent:
58.28% (G:14.11% B:0.58%) 41.72% (G:9.64% B:0.29%)
41: 11/7 8/7
XGID=-a----E-C--AfD---b-db--AA-:0:0:1:41:0:0:0:11:10 Pip=164-152
1. 4-ply 11/7 8/7 eq: -0.405
Player: Opponent:
39.21% (G:8.62% B:0.25%) 60.79% (G:14.47% B:0.62%)
“Lover’s leap” would be the play virtually everyone would make but this is one of those situations
where the stronger board, the unstacking of the midpoint and the replenishing of the 8 point
combine to make 24/13 a very close second best
62: 24/16
XGID=-a----EBB---fD---b-db--AA-:0:0:-1:62:0:0:0:11:10 Pip=159-152
1. 4-ply 24/16 eq: +0.372
Player: Opponent:
60.82% (G:10.61% B:0.37%) 39.18% (G:7.60% B:0.21%)
2. 4-ply 13/5 eq: +0.367 (-0.005) Player:
Opponent: 59.22% (G:15.45% B:0.60%) 40.78% (G:9.13% B:0.28%)
63: 24/18 13/10
XGID=------EBBa--fD---b-db--AA-:0:0:1:63:0:0:0:11:10 Pip=159-144
1. XG Roller++ 24/21 13/7 eq: -0.569
When ahead or even in a race, the chance of escaping the back man at the expense of a single
shot is always a contender for best play
Player: Opponent:
34.51% (G:4.71% B:0.16%) 65.49% (G:11.20% B:0.33%)
2. XG Roller++ 24/18 13/10 eq: -0.701 (-0.132)
Player: Opponent:
32.76% (G:5.15% B:0.17%) 67.24% (G:16.11% B:0.67%)
3. 4-ply 13/7 6/3 eq: -0.612 (-0.042) Player:
Opponent: 32.94% (G:5.30% B:0.12%) 67.06% (G:11.40% B:0.42%)
4. 4-ply 13/4 eq: -0.615 (-0.046) Player:
Opponent: 32.82% (G:5.35% B:0.12%) 67.18% (G:11.54% B:0.44%)
5. 4-ply 24/18 6/3 eq: -0.626 (-0.057) Player:
Opponent: 33.51% (G:5.05% B:0.17%) 66.49% (G:14.37% B:0.50%)
No double
XGID=------EBBaA-fC---bAdb--A--:0:0:-1:00:0:0:0:11:10 Pip=150-144
Analyzed in XG Roller++ No double Double/Take Player Winning Chances: 67.44% (G:16.01% B:0.64%) 67.47% (G:16.24% B:0.66%) Opponent Winning Chances: 32.56% (G:5.04% B:0.17%) 32.53% (G:5.02% B:0.17%) Cubeless Equities +0.465 +0.951
Cubeful Equities
No double: +0.694 (-0.018)
Double/Take: +0.712
Double/Pass: +1.000 (+0.288)
Best Cube action: Double / Take
Duplication for the sake of it and asking for contact with a weaker board. The first blunder of the
match.
Andy misses this double, but few would see it. The position looks innocuous but 24% of the time
you do lose your market (most double hits and large sets)
62: 16/14 13/7*
XGID=------EBBaA-fC---bAdb--A--:0:0:-1:62:0:0:0:11:10 Pip=150-144
1. XG Roller++ 13/7* 7/5 eq: +0.684
Player: Opponent:
66.96% (G:16.26% B:0.70%) 33.04% (G:6.53% B:0.22%)
2. XG Roller++ 16/14 13/7* eq: +0.530 (-0.154)
Player: Opponent:
63.14% (G:15.68% B:0.70%) 36.86% (G:8.19% B:0.32%)
3. 4-ply 13/11 13/7* eq: +0.577 (-0.107) Player:
Opponent: 64.47% (G:17.16% B:0.76%) 35.53% (G:8.09% B:0.35%)
4. 4-ply 16/8 eq: +0.534 (-0.150) Player:
Opponent: 65.12% (G:7.22% B:0.18%) 34.88% (G:2.68% B:0.08%)
32: Bar/22 13/11*
Andy’s turn to blunder. Getting hit on the bar point would give White a good chance to
subsequently make it and get a foothold in the game. Far better to pick and pass and leave the
blot on the 16pt, if this gets hit it’s no big deal.
XGID=------EBB-AaeC---badb--A-A:0:0:1:32:0:0:0:11:10 Pip=157-136
1. 3-ply Bar/22 13/11* eq: -0.348
Player: Opponent:
41.43% (G:10.71% B:0.37%) 58.57% (G:17.63% B:1.02%)
65: Bar/20 13/7
XGID=a-----EBB-AAeB---badb-AA--:0:0:-1:65:0:0:0:11:10 Pip=152-147
1. XG Roller++ Bar/14* eq: +0.601
Player: Opponent:
64.48% (G:18.54% B:1.14%) 35.52% (G:8.27% B:0.36%)
2. XG Roller++ Bar/20 13/7 eq: +0.558 (-0.043)
Player: Opponent:
63.71% (G:16.58% B:0.88%) 36.29% (G:9.07% B:0.25%)
41: 11/7 6/5*
XGID=-----aEBB-AAdB---bbdb-AA--:0:0:1:41:0:0:0:11:10 Pip=152-136
1. 4-ply 11/7 6/5* eq: -0.806
Player: Opponent:
32.26% (G:6.82% B:0.23%) 67.74% (G:21.50% B:1.36%)
2. 4-ply 23/22 11/7 eq: -0.826 (-0.020) Player:
Opponent: 27.68% (G:3.59% B:0.09%) 72.32% (G:9.29% B:0.26%)
Double/Take
Tempting to make the 4 prime but Black will find his lone man under attack. Although White only
has a one-point board at present, he has 11 men in the zone (‘men in the zone’ by the way are
checkers that make a point in board or checkers that are within six points of any open point in
board).
A useful rule of thumb when thinking of whether to blitz: If you have less than 9 in the zone –
forget it.
XGID=a----ADCB-A-dB---bbdb-AA--:0:0:-1:00:0:0:0:11:10 Pip=147-141
Analyzed in 4-ply No double Double/Take Player Winning Chances: 67.73% (G:21.52% B:1.36%) 67.74% (G:21.50% B:1.36%) Opponent Winning Chances: 32.27% (G:6.83% B:0.23%) 32.26% (G:6.82% B:0.23%) Cubeless Equities +0.516 +1.049
Cubeful Equities
No double: +0.728 (-0.077)
Double/Take: +0.806
Double/Pass: +1.000 (+0.194)
Best Cube action: Double / Take
21: Bar/22
Doubling from the bar is often missed by beginners. Here Andy correctly seizes the opportunity.
With four juicy blots for the taking things could go very well indeed for Black and there are only
very few sequences in the immediate next two rolls where White can become a favourite.
XGID=a----ADCB-A-dB---bbdb-AA--:1:1:-1:21:0:0:0:11:10 Pip=147-141
1. 4-ply Bar/22 eq: +0.124
Player: Opponent:
60.35% (G:15.49% B:0.74%) 39.65% (G:10.29% B:0.30%)
2. 4-ply Bar/24 13/11 eq: +0.094 (-0.030) Player:
Opponent: 58.62% (G:16.84% B:0.72%) 41.38% (G:10.35% B:0.38%)
3. 4-ply Bar/23 6/5 eq: +0.086 (-0.038) Player:
Opponent: 58.32% (G:17.15% B:0.77%) 41.68% (G:10.78% B:0.36%)
62: 22/16 7/5
XGID=---a-ADCB-A-dB---bbdb-AA--:1:1:1:62:0:0:0:11:10 Pip=147-138
1. 4-ply 22/16 7/5 eq: -0.160
Player: Opponent:
38.78% (G:8.76% B:0.26%) 61.22% (G:15.76% B:0.67%)
2. 4-ply 10/4 7/5 eq: -0.283 (-0.123) Player:
Opponent: 35.46% (G:8.74% B:0.33%) 64.54% (G:19.84% B:1.03%)
64: 22/16 13/9*
A poor roll from Andy but he plays it well. He needs to step up to prevent being stuck behind the
upcoming prime.
XGID=---a-BDBB-A-dB--Abbdb--A--:1:1:-1:64:0:0:0:11:10 Pip=139-138
1. 4-ply 22/16 13/9* eq: +0.316
Player: Opponent:
67.19% (G:15.91% B:0.72%) 32.81% (G:7.70% B:0.29%)
2. 4-ply 13/7 13/9* eq: +0.179 (-0.137) Player:
Opponent: 61.36% (G:17.51% B:0.81%) 38.64% (G:9.14% B:0.33%)
52: Bar/23 10/5
XGID=-----BDBBaA-cB--abbdb--A-A:1:1:1:52:0:0:0:11:10 Pip=148-128
1. 4-ply Bar/23 10/5 eq: -0.540
Player: Opponent:
21.95% (G:2.35% B:0.05%) 78.05% (G:7.63% B:0.22%)
63: 16/10 13/10
Nice roll, simultaneously hitting and escaping.
XGID=-----CDBBa--cB--abbdb--B--:1:1:-1:63:0:0:0:11:10 Pip=141-128
1. 4-ply 16/10 13/10 eq: +0.532
Player: Opponent:
77.84% (G:7.90% B:0.25%) 22.16% (G:2.86% B:0.08%)
2. 4-ply 16/7 eq: +0.493 (-0.039) Player:
Opponent: 76.41% (G:7.44% B:0.21%) 23.59% (G:2.89% B:0.06%)
3. 4-ply 16/10 9/6 eq: +0.472 (-0.060) Player:
Opponent: 75.68% (G:6.80% B:0.17%) 24.32% (G:2.64% B:0.05%)
42: 8/4 6/4
Should be plain sailing for Andy from now on. He is hoping to break from the midpoint, make the
4pt and 3 pt in turn, whilst keeping the spare checkers in front of the anchor, and then to clear
from the back. He might need to take some slight risks in the short run to achieve this. With his
race lead he should win this game if he avoids being hit.
XGID=-----CDBB---bB-babbdb--B--:1:1:1:42:0:0:0:11:10 Pip=141-119
1. 4-ply 8/4 6/4 eq: -0.587
Player: Opponent:
19.77% (G:1.64% B:0.03%) 80.23% (G:6.52% B:0.17%)
65: 10/4 9/4
XGID=----BCCBA---bB-babbdb--B--:1:1:-1:65:0:0:0:11:10 Pip=135-119
1. 4-ply 10/4 9/4 eq: +0.654
Player: Opponent:
82.76% (G:6.47% B:0.16%) 17.24% (G:0.87% B:0.02%)
64: 8/2 6/2
Robin, on the other hand, needs to patiently build his board in the hope that if and when the shot
comes he instantly wins with a hit. He is in no danger of being gammoned so does not need to
pile his men on the 6 point.
XGID=----BCCBA---bB-a-bbdbb-B--:1:1:1:64:0:0:0:11:10 Pip=135-108
1. XG Roller++ 8/2 6/2 eq: -0.657
Player: Opponent:
17.07% (G:0.81% B:0.01%) 82.93% (G:6.25% B:0.14%)
2. XG Roller++ 8/2 7/3 eq: -0.661 (-0.004) Player:
Opponent: 17.32% (G:0.98% B:0.02%) 82.68% (G:7.25% B:0.27%)
53: 13/10 13/8
XGID=--B-BCBB----bB-a-bbdbb-B--:1:1:-1:53:0:0:0:11:10 Pip=125-108
1. 4-ply 13/10 13/8 eq: +0.656
Player: Opponent:
83.03% (G:5.78% B:0.09%) 16.97% (G:0.52% B:0.01%)
63: 13/4
XGID=--B-BCBB-----B-b-cbdbb-B--:1:1:1:63:0:0:0:11:10 Pip=125-100
1. 4-ply 13/4 eq: -0.669
Player: Opponent:
16.33% (G:0.52% B:0.00%) 83.67% (G:5.61% B:0.11%)
54: 10/5 8/4
XGID=--B-CCBB-----A-b-cbdbb-B--:1:1:-1:54:0:0:0:11:10 Pip=116-100
1. 4-ply 10/5 8/4 eq: +0.634
Player: Opponent:
82.19% (G:5.61% B:0.08%) 17.81% (G:0.51% B:0.01%)
43: 7/3 4/1
XGID=--B-CCBB-----A-a-bbdcc-B--:1:1:1:43:0:0:0:11:10 Pip=116-91
1. XG Roller++ 13/10 7/3 eq: -0.620 Player:
Opponent: 18.22% (G:0.96% B:0.01%) 81.78% (G:5.35% B:0.11%)
2. XG Roller++ 7/3 4/1 eq: -0.627 (-0.006)
Player: Opponent:
18.24% (G:0.89% B:0.01%) 81.76% (G:5.70% B:0.18%)
31: 6/3 4/3
XGID=-ABABCBA-----A-a-bbdcc-B--:1:1:-1:31:0:0:0:11:10 Pip=109-91
1. 4-ply 6/3 4/3 eq: +0.749
Player: Opponent:
86.71% (G:6.07% B:0.10%) 13.29% (G:0.22% B:0.01%)
22: 7/1 5/3
XGID=-ABABCBA-----A-a-bbccbbB--:1:1:1:22:0:0:0:11:10 Pip=109-87
1. 4-ply 7/1 5/3 eq: -0.736
Player: Opponent:
13.53% (G:0.34% B:0.00%) 86.47% (G:5.50% B:0.07%)
62: 10/4 5/3
XGID=-BBBBBB------A-a-bbccbbB--:1:1:-1:62:0:0:0:11:10 Pip=101-87
1. 4-ply 10/4 5/3 eq: +0.729
Player: Opponent:
86.23% (G:5.08% B:0.09%) 13.77% (G:0.26% B:0.00%)
62: 13/5
XGID=-BBBBBB------A---bbcbccB--:1:1:1:62:0:0:0:11:10 Pip=101-79
1. 4-ply 13/5 eq: -0.703
Player: Opponent:
14.67% (G:0.44% B:0.00%) 85.33% (G:4.72% B:0.06%)
44: 8/4(2) 7/3(2)
XGID=-BBBBCB----------bbcbccB--:1:1:-1:44:0:0:0:11:10 Pip=93-79
1. 4-ply 8/4(2) 7/3(2) eq: +0.784
Player: Opponent:
88.97% (G:3.48% B:0.07%) 11.03% (G:0.01% B:0.00%)
63: 23/14
XGID=-BBBBCB------------cbeeB--:1:1:1:63:0:0:0:11:10 Pip=93-63
1. 4-ply 23/14 eq: -0.763
Player: Opponent:
11.42% (G:0.01% B:0.00%) 88.58% (G:2.17% B:0.02%)
54: 6/1 4/Off
XGID=-BBBBCB-------A----cbeeA--:1:1:-1:54:0:0:0:11:10 Pip=84-63
1. 4-ply 6/1 4/Off eq: +0.826
Player: Opponent:
91.91% (G:1.03% B:0.02%) 8.09% (G:0.00% B:0.00%)
32: 14/9
XGID=-BBBBCB-------A----bbdeAa-:1:1:1:32:0:0:0:11:10 Pip=84-54
1. 4-ply 14/9 eq: -0.853
Player: Opponent:
7.00% (G:0.00% B:0.00%) 93.00% (G:1.25% B:0.01%)
64: 6/Off 4/Off
XGID=-BBBBCB--A---------bbdeAa-:1:1:-1:64:0:0:0:11:10 Pip=79-54
1. 3-ply 6/Off 4/Off eq: +0.317
Player: Opponent:
67.99% (G:0.81% B:0.01%) 32.01% (G:0.00% B:0.00%)
43: 23/19* 9/6
Whoops!
XGID=-BBBBCB--A---------abceAa-:1:1:1:43:0:0:0:11:10 Pip=79-44
1. 4-ply 23/19* 9/6 eq: +1.000
Player: Opponent:
93.52% (G:0.00% B:0.00%) 6.48% (G:0.00% B:0.00%)
Cannot Move
Double/Pass
XGID=aBBBBCC------------Abce-a-:1:1:1:00:0:0:0:11:10 Pip=72-63
The real skill in backgammon! Surprisingly we had to wait till move 16 for our first joker or
antijoker (you saw the Emoji? ) and then two come at once! First blood to Robin.
A joker by the way is a (lucky) roll that increases one’s equity by over 300 millipoints; an anti-
joker is the opposite.
Analyzed in 4-ply No redouble Redouble/Take Player Winning Chances: 93.52% (G:0.00% B:0.00%) 93.52% (G:0.00% B:0.00%) Opponent Winning Chances: 6.48% (G:0.00% B:0.00%) 6.48% (G:0.00% B:0.00%) Cubeless Equities +0.870 +1.779
Cubeful Equities
No redouble: +1.000
Redouble/Take: +1.727 (+0.727)
Redouble/Pass: +1.000
Best Cube action: Redouble / Pass
Wins 2pts.
Game Summary:
robin swaffield Category andy darby
World Class (-0.0081) Total Error Expert (-0.0101)
World Class (-0.0086) Checker Play Expert (-0.0128)
World Champ. (+0.0000) Cube Play World Champ. (-0.0030)
4.05 Performance Rating 5.06
1(1) Move Errors 2(1)
-0.138(-0.70%) Equity lost (cost) -0.205(-0.99%)
0 Double Errors 0
+0.000 Equity lost (cost) -0.018(-0.09%)
0 Take Errors 0
+0.000 Equity lost (cost) +0.000
1(1) Total Error 2(1)
-0.138(-0.70%) Equity lost (cost) -0.223(-1.08%)
2 Jokers 0
+0.532(+9.59%) Luck -0.532(-9.59%)