Game number 3

The score (after 2 games) is: White 1, Black 4 (match to 7 points)

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Match Information

Date	août 05, 2008
Place	Slot Backgammon training match
Annotator	Fabrice Liardet
Comment	This match is played with the rules of Nack Ballard's Slot Backgammon, which state that the first move of the game must always be "a slot", which means a move that leaves a blot in direct range of the opponent's rear checkers (points 7 to 2).

Move number 1: White to play 52

+-12-11-10--9--8--7-+---+--6--5--4--3--2--1-+

+-13-14-15-16-17-18-+---+-19-20-21-22-23-24-+

Pip counts: White 167, Black 167
Position ID: 4HPwATDgc/ABMA Match ID: MIDqABAAIAAA

• White moves 13/8 6/4

#		Ply	Move	Equity
			13/8 6/4

Move number 2: Black to play 65

Pip counts: White 160, Black 167
Position ID: yPPgATDgc/ABMA Match ID: cAn3ABAAIAAA

• Black moves 24/13

#		Ply	Move	Equity
•	1	2	24/13	-0,221
			0,488 0,103 0,004 - 0,512 0,152 0,004
	2	2	24/18 13/8	-0,327 ( -0,107)
			0,466 0,112 0,005 - 0,534 0,169 0,005
	3	2	13/8 13/7	-0,380 ( -0,159)
			0,451 0,129 0,006 - 0,549 0,169 0,009
	4	0	24/18 8/3	-0,419 ( -0,198)
			0,443 0,115 0,007 - 0,557 0,195 0,009
	5	0	13/2	-0,425 ( -0,205)
			0,435 0,127 0,007 - 0,565 0,180 0,011

Move number 3: White to play 52

Pip counts: White 160, Black 156
Position ID: 4HPwAyDI8+ABMA Match ID: MIHqABAAIAAA

• White moves 13/8 6/4

Cube decision
2-ply cubeless equity		+0,055	(Money: +0,072)
	0,512 0,152 0,004 - 0,488 0,103 0,004
Cubeful equities:
1.	No double	+0,221
2.	Double, pass	+1,000	+0,779
3.	Double, take	+0,091	-0,129
Proper cube action:		No double, take (14,2%)

#		Ply	Move	Equity
•	1	2	13/8 6/4	+0,196
			0,510 0,144 0,003 - 0,490 0,104 0,003
	2	2	8/3 6/4	+0,154 ( -0,042)
			0,496 0,151 0,004 - 0,504 0,116 0,005
	3	2	6/4 6/1*	+0,107 ( -0,089)
			0,486 0,140 0,003 - 0,514 0,120 0,005
	4	0	24/22 13/8	-0,015 ( -0,211)
			0,459 0,115 0,003 - 0,541 0,128 0,003
	5	0	13/11 13/8	-0,025 ( -0,221)
			0,453 0,125 0,003 - 0,547 0,136 0,006

Move number 4: Black to play 63

Pip counts: White 153, Black 156
Position ID: mPPBATDgc/ADIA Match ID: cAnvABAAIAAA

• Black moves 24/15

#		Ply	Move	Equity
•	1	2	24/15	-0,227
			0,486 0,078 0,002 - 0,514 0,137 0,003
	2	2	24/18 13/10	-0,398 ( -0,171)
			0,453 0,089 0,003 - 0,547 0,181 0,005
	3	0	13/10 13/7	-0,406 ( -0,179)
			0,445 0,113 0,005 - 0,555 0,190 0,008
	4	0	13/4	-0,436 ( -0,209)
			0,437 0,105 0,004 - 0,563 0,191 0,007
	5	0	13/7 6/3	-0,588 ( -0,361)
			0,418 0,104 0,004 - 0,582 0,216 0,010

Annotation

After having escaped one checker, Black's plan is clearly to escape the second one.

Move number 5: White to play 53

Pip counts: White 153, Black 147
Position ID: 4HPwEwCY88EBMA Match ID: MIHuABAAIAAA

• White moves 13/10* 8/3

Cube decision
2-ply cubeless equity		+0,075	(Money: +0,087)
	0,514 0,137 0,003 - 0,486 0,078 0,002
Cubeful equities:
1.	No double	+0,227
2.	Double, pass	+1,000	+0,773
3.	Double, take	+0,078	-0,149
Proper cube action:		No double, take (16,2%)

#		Ply	Move	Equity
•	1	2	13/10* 8/3	+0,450
			0,551 0,206 0,006 - 0,449 0,102 0,005
	2	2	13/10*/5	+0,447 ( -0,003)
			0,552 0,197 0,005 - 0,448 0,094 0,003
	3	2	13/10* 13/8	+0,371 ( -0,080)
			0,540 0,181 0,004 - 0,460 0,089 0,003
	4	0	13/10* 6/1	+0,238 ( -0,212)
			0,510 0,174 0,004 - 0,490 0,110 0,004
	5	0	24/21 8/3	+0,079 ( -0,372)
			0,483 0,107 0,001 - 0,517 0,070 0,002

Annotation

The 5 point is the point that White really needs, so slotting is beneficial to him, but then there is that huge stack on the 8 point crying to be developed. I thought that a good distribution was more important, while in fact it is a photo.

Move number 6: Black to play 44

Pip counts: White 145, Black 157
Position ID: NOeJATDgc/ADQA Match ID: cAnyABAAIAAA

• Black cannot move

Alert: very unlucky roll! ( -0,604)

#		Ply	Move	Equity
			Cannot move

Move number 7: White to play 64

Pip counts: White 145, Black 157
Position ID: 4HPwA0A054kBMA Match ID: MAHzABAAIAAA

• White moves 13/3

Alert: missed double ( -0,083)! [very bad]

Cube decision

Rollout cubeless equity

+0,555

(Money: +0,538)

Cubeful equities:

Double, pass

+1,000

Double, take

+1,181

+0,181

No double

+0,917

-0,083

Proper cube action:

Double, pass

Rollout details

	Win	W g	W bg		Lose	L g	L bg	Cubeless	Cubeful
Centered 1-cube	0,652	0,296	0,008	-	0,348	0,067	0,003	+0,555	+0,917
Standard error	0,001	0,001	0,000	-	0,001	0,001	0,000	0,002	0,003
Player Black owns 2-cube	0,665	0,305	0,008	-	0,335	0,067	0,003	+1,253	+1,181
Standard error	0,001	0,001	0,000	-	0,001	0,001	0,000	0,004	0,004

Truncated cubeful rollout (depth 11) with var.redn.

1296 games, Mersenne Twister dice gen. with seed 837397995 and quasi-random dice

Play: world class 2-ply cubeful prune [world class]

keep the first 0 0-ply moves and up to 8 more moves within equity 0,16

Skip pruning for 1-ply moves.

Cube: 2-ply cubeful prune [world class]

#		Ply	Move	Equity
•	1	0	13/3	+0,869
			0,651 0,318 0,007 - 0,349 0,066 0,002
	2	0	8/2 6/2	+0,692 ( -0,178)
			0,603 0,279 0,008 - 0,397 0,087 0,004
	3	0	24/20 10/4	+0,579 ( -0,291)
			0,591 0,224 0,005 - 0,409 0,076 0,002
	4	0	24/14	+0,561 ( -0,308)
			0,591 0,216 0,005 - 0,409 0,086 0,003
	5	0	24/18 8/4	+0,547 ( -0,323)
			0,582 0,226 0,006 - 0,418 0,095 0,003

Annotation

White is almost sure to cover the blot in his home board. If as I thought he can still cash after he does so and Black enters without a double or a hit, then it is too good to double and he should give the undoubled gammon a try. As we will see after that happens in the game, those variations don't allow White to cash and he should cash now.

Move number 8: Black to play 31

Pip counts: White 135, Black 157
Position ID: bM4TATDgc/ADQA Match ID: cInlABAAIAAA

• Black moves bar/24 13/10

#		Ply	Move	Equity
•	1	2	bar/24 13/10	-0,792
			0,400 0,082 0,004 - 0,600 0,271 0,008
	2	2	bar/24 6/3	-1,000 ( -0,208)
			0,351 0,073 0,003 - 0,649 0,341 0,013
	3	2	bar/24 8/5	-1,000 ( -0,208)
			0,348 0,072 0,003 - 0,652 0,335 0,014

Annotation

Let's do our take point calculation again from Black's point of view : winning double is 89%, losing single is 65%, and losing double is somewhere between 40% and 57.5%. A 40% gammon rate would make it a little less than 50% but seems to be on the low side. I think 49% is a good figure for Black losing a doubled game. That makes the take point 16/40 = 40%. Very high, so it has to be a correct double, and it is rather the take which is in question.

Move number 9: White doubles to 2

Pip counts: White 135, Black 153
Position ID: 4HPiAyBszhMBMA Match ID: MBngABAAIAAA

• Black rejects

Alert: wrong pass ( -0,057)! [very bad]

Cube decision

Rollout cubeless equity

+0,466

(Money: +0,434)

Cubeful equities:

Double, take

+0,943

Double, pass

+1,000

+0,057

No double

+0,791

-0,152

Proper cube action:

Double, take

Rollout details

	Win	W g	W bg		Lose	L g	L bg	Cubeless	Cubeful
Centered 1-cube	0,617	0,275	0,008	-	0,383	0,078	0,004	+0,466	+0,791
Standard error	0,001	0,001	0,000	-	0,001	0,001	0,000	0,003	0,004
Player Black owns 2-cube	0,623	0,286	0,008	-	0,377	0,076	0,004	+1,021	+0,943
Standard error	0,001	0,001	0,000	-	0,001	0,001	0,000	0,005	0,005

Truncated cubeful rollout (depth 11) with var.redn.

1296 games, Mersenne Twister dice gen. with seed 837397995 and quasi-random dice

Play: world class 2-ply cubeful prune [world class]

keep the first 0 0-ply moves and up to 8 more moves within equity 0,16

Skip pruning for 1-ply moves.

Cube: 2-ply cubeful prune [world class]

Annotation

At first sight 40% seems much to ask for. But Black is not that far of it, with only one checker back which is relatively safe, and still definite chances of priming White's two unmoved back checkers. Still, as I expected GNU says that Black just doesn't get those 40% of wins, and still has a take. What happens ?

The difference was small enough for being undone by the two factors we neglected in our calculations. Black's gammons and Black's redoubles. Small factors since the difference between a 6-1 lead (89% match equity) and a win is small, but big enough for shifting the take point by 2%, if GNU's "market window" values are correct. Anyway that makes enough sense for me not trying to dispute it by more precise computations.

White wins 1 point

Game statistics for game 3
Player	White	Black
Checker play statistics
Total moves	4	4
Unforced moves	3	3
Unmarked moves	1	0
Moves marked good	3	4
Moves marked doubtful	0	0
Moves marked bad	0	0
Moves marked very bad	0	0
Error rate (total)	+0,000	+0,000
Error rate (per move)	+0,0	+0,0
Chequerplay rating	Supernatural	Supernatural
Luck statistics
Rolls marked very lucky	0	0
Rolls marked lucky	0	0
Rolls unmarked	3	3
Rolls marked unlucky	0	0
Rolls marked very unlucky	0	1
Luck rate (total)	+0,135 ( +1,022%)	-0,925 ( -7,014%)
Luck rate (per move)	+33,7 ( +0,256%)	-231,2 ( -1,754%)
Luck rating	Good dice, man!	Haaa-haaa
Cube statistics
Total cube decisions	4	5
Close or actual cube decisions	4	1
Doubles	1	0
Takes	0	0
Passes	0	1
Missed doubles (below CP)	0	0
Missed doubles (above CP)	1 (-0,083 ( -0,630%))	0
Wrong doubles (below DP)	0	0
Wrong doubles (above TG)	0	0
Wrong takes	0	0
Wrong passes	0	1 (-0,057 ( -0,431%))
Error rate (total)	-0,083 ( -0,630%)	-0,057 ( -0,431%)
Error rate (per cube decision)	-20,8 ( -0,157%)	-56,8 ( -0,431%)
Cube decision rating	Casual player	Awful!
Overall statistics
Error rate (total)	-0,083 ( -0,630%)	-0,057 ( -0,431%)
Error rate (per decision)	-11,9 ( -0,090%)	-14,2 ( -0,108%)
Equiv. Snowie error rate	-10,4	-7,1
Overall rating	Advanced	Intermediate
Actual result	+6,40%	-6,40%
Luck adjusted result	-1,64%	+1,64%

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Output generated Tue Sep 09 12:27:47 2008 by GNU Backgammon 0.16-mingw (HTML Export version 1.172)