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%)