Game number 4

The score (after 3 games) is: Rida Hassan 1, Johan Segers 5 (match to 9 points)

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Match Information

Date	januari 04, 2009
Event	5th Backgammon Masters
Round	8
Place	Antwerp, Belgium
Annotator	Johan Segers
Comment	The 2009 Masters tournament took place in Antwerp on 3 - 4 January. The tournament format was 9 rounds Swiss, with matches being played to 9 points and timed with electronic clocks (Bronstein system, 15 minutes for the match plus 15 seconds per move). The following analysis is performed with the help of GNU Backgammon at 3-ply search depth, setting "grandmaster". In cases of doubt, roll-outs have been done.

Move number 1: Rida Hassan to play 25

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

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

Pip counts: Rida Hassan 167, Johan Segers 167
Position ID: 4HPwATDgc/ABMA Match ID: MAA1ARAAKAAA

• Rida Hassan moves 13/11 13/8

#		Ply	Move	MWC
•	1	3	13/11 13/8	25,15%
			49,3 14,4 0,6 - 50,7 14,0 0,6
	2	3	24/22 13/8	25,10% ( -0,05%)
			49,6 13,3 0,4 - 50,4 13,0 0,4
	3	2	13/8 6/4	25,11% ( -0,04%)
			49,6 13,9 0,5 - 50,4 14,0 0,6
	4	2	13/6	24,97% ( -0,18%)
			48,8 13,8 0,6 - 51,2 14,3 0,5
	5	2	13/11 8/3	24,61% ( -0,54%)
			47,0 14,0 0,6 - 53,0 16,0 0,9

Annotation

In normal circumstances, the rollouts say that 24/22 13/8 is the best way to open with 5-2, despite the immediate risk of being blown away with Black's double fives. However, being far behind in the match, White is at "gammon-go", that is, he is actively looking for gammonish positions. The move played, 13/11 13/8, is an attacking move aiming at just that.

Move number 2: Johan Segers to play 21

Pip counts: Rida Hassan 160, Johan Segers 167
Position ID: 4PPIATDgc/ABMA Match ID: cAklARAAKAAA

• Johan Segers moves 24/23 13/11

#		Ply	Move	MWC
	1	3	13/11 6/5	73,74%
			46,4 13,1 0,5 - 53,6 17,3 1,2
•	2	3	24/23 13/11	73,70% ( -0,04%)
			45,6 12,5 0,4 - 54,4 16,9 0,7
	3	2	13/10	73,94% ( 0,20%)
			46,6 12,8 0,5 - 53,4 15,9 0,8
	4	2	24/21	73,91% ( 0,17%)
			46,6 11,5 0,5 - 53,4 16,0 0,6
	5	2	24/23 24/22	73,68% ( -0,06%)
			45,7 11,4 0,5 - 54,3 16,9 0,6

Annotation

According to the rollouts, the best way to play 21 in this position is 13/11 6/5, whatever the match score. [At "gammon-save", the opposite of "gammon-go", an almost equal alternative is the surprising 24/21, going for the advanced anchor immediately.] The normal-looking 24/23 13/11 is far worse.

According to a 2007 article by Bill Robertie, the reason is that since in the opening move White has brought two builders down, Black should not split his back chequers because of the increased risk they get attacked. Instead, Black should leave the back chequers safely together and do something constructive on his own side of the board.

In the game, the punishment of my error is severe.

Move number 3: Rida Hassan to play 55

Pip counts: Rida Hassan 160, Johan Segers 164
Position ID: 4HPkASjg88gBMA Match ID: MIE2ARAAKAAA

• Rida Hassan moves 8/3(2) 6/1*(2)

Cube decision
3-ply cubeless MWC		25,05%	(Money: +0,135)
	54,4 16,9 0,7 - 45,6 12,5 0,4
Cubeful equities:
1.	No double	26,30%
2.	Double, pass	29,81%	3,52%
3.	Double, take	25,76%	-0,54%
Proper cube action:		No double, take (13,3%)

Alert: lucky roll! (+2,186%)

#		Ply	Move	MWC
•	1	0	8/3(2) 6/1*(2)	28,44%
			60,5 29,3 1,2 - 39,5 10,5 0,4
	2	0	13/8 11/1* 6/1	26,63% ( -1,81%)
			54,4 21,3 0,7 - 45,6 13,0 0,4
	3	0	13/3 8/3 6/1*	26,40% ( -2,03%)
			53,2 20,8 1,0 - 46,8 12,9 0,6
	4	0	13/3 11/6 8/3	26,24% ( -2,20%)
			53,2 19,4 0,7 - 46,8 13,7 0,5
	5	0	11/1* 8/3(2)	26,19% ( -2,24%)
			52,3 20,0 0,9 - 47,7 12,9 0,5

Move number 4: Johan Segers to play 64

Pip counts: Rida Hassan 140, Johan Segers 165
Position ID: M87IATDgc+QBSA Match ID: cAkzARAAKAAA

• Johan Segers moves bar/21 11/5

#		Ply	Move	MWC
•	1	2	bar/21 11/5	71,27%
			41,8 11,3 0,6 - 58,2 30,1 1,5
	2	2	bar/21 13/7	70,19% ( -1,07%)
			39,6 10,8 0,5 - 60,4 32,4 2,3
	3	2	bar/15	70,19% ( -1,08%)
			39,3 9,6 0,5 - 60,7 33,9 1,3
	4	2	bar/21 8/2	70,19% ( -1,08%)
			36,6 9,6 0,4 - 63,4 34,7 2,2

Move number 5: Rida Hassan on roll, cube decision?

Pip counts: Rida Hassan 140, Johan Segers 155
Position ID: 0OfgARIzzsgBMA Match ID: MAEgARAAKAAA

• Rida Hassan doubles

Cube decision

Rollout cubeless MWC

26,51%

(Money: +0,337)

Cubeful equities:

Double, take

28,80%

Double, pass

29,81%

1,01%

No double

27,58%

-1,22%

Proper cube action:

Double, take

Rollout details

	Win	W g	W bg		Lose	L g	L bg	Cubeless	Cubeful
Centered 1-cube	58,1	29,1	0,9	-	41,9	11,3	1,2	26,51%	27,58%
Standard error	0,5	0,6	0,2	-	0,5	0,7	0,5	0,09%	0,21%
Player Johan Segers owns 2-cube	59,0	29,0	1,0	-	41,0	12,4	1,7	29,07%	28,80%
Standard error	0,6	0,6	0,4	-	0,6	1,0	0,7	0,21%	0,26%

Full cubeful rollout with var.redn.

144 games, Mersenne Twister dice gen. with seed 867997887 and quasi-random dice

Play: 0-ply cubeful prune [expert]

Cube: 0-ply cubeful prune [expert]

Annotation

White is looking forward to blow Black into pieces. The air carries a strong gammon smell. Flip that cube.

Move number 6: Rida Hassan doubles to 2

Pip counts: Rida Hassan 140, Johan Segers 155
Position ID: 0OfgARIzzsgBMA Match ID: MBkgARAAKAAA

• Johan Segers rejects

Alert: wrong pass ( -1,01%)!

Cube decision

Rollout cubeless MWC

26,51%

(Money: +0,337)

Cubeful equities:

Double, take

28,80%

Double, pass

29,81%

1,01%

No double

27,58%

-1,22%

Proper cube action:

Double, take

Rollout details

	Win	W g	W bg		Lose	L g	L bg	Cubeless	Cubeful
Centered 1-cube	58,1	29,1	0,9	-	41,9	11,3	1,2	26,51%	27,58%
Standard error	0,5	0,6	0,2	-	0,5	0,7	0,5	0,09%	0,21%
Player Johan Segers owns 2-cube	59,0	29,0	1,0	-	41,0	12,4	1,7	29,07%	28,80%
Standard error	0,6	0,6	0,4	-	0,6	1,0	0,7	0,21%	0,26%

Full cubeful rollout with var.redn.

144 games, Mersenne Twister dice gen. with seed 867997887 and quasi-random dice

Play: 0-ply cubeful prune [expert]

Cube: 0-ply cubeful prune [expert]

Annotation

Given my lead in the match, I decided to pass, to avoid losing a doubled gammon. However, not having any chequer on the bar for now, Black can take. If Black manages to anchor, which seems not too unlikely, White will have a long way to go, for the two White chequers buried on the ace-point will compromise White's flexibility for the rest of the game.

Rida Hassan wins 1 point

Game statistics for game 4
Player	Rida Hassan	Johan Segers
Checker play statistics
Total moves	2	2
Unforced moves	2	2
Unmarked moves	2	2
Moves marked doubtful	0	0
Moves marked bad	0	0
Moves marked very bad	0	0
Error total EMG (MWC)	+0,000 ( +0,000%)	-0,007 ( -0,038%)
Error rate mEMG (MWC)	+0,0 ( +0,000%)	-3,6 ( -0,019%)
Chequerplay rating	Supernatural	World class
Luck statistics
Rolls marked very lucky	0	0
Rolls marked lucky	1	0
Rolls unmarked	1	2
Rolls marked unlucky	0	0
Rolls marked very unlucky	0	0
Luck total EMG (MWC)	+0,449 ( +2,406%)	-0,408 ( -2,189%)
Luck rate mEMG (MWC)	+224,4 ( +1,203%)	-204,2 ( -1,095%)
Luck rating	Go to Las Vegas	Go to bed
Cube statistics
Total cube decisions	2	3
Close or actual cube decisions	2	1
Doubles	1	0
Takes	0	0
Passes	0	1
Missed doubles below CP (EMG (MWC))	0	0
Missed doubles above CP (EMG (MWC))	0	0
Wrong doubles below DP (EMG (MWC))	0	0
Wrong doubles above TG (EMG (MWC))	0	0
Wrong takes (EMG (MWC))	0	0
Wrong passes (EMG (MWC))	0	1 (-0,189 ( -1,015%))
Error total EMG (MWC)	+0,000 ( +0,000%)	-0,189 ( -1,015%)
Error rate mEMG (MWC)	+0,0 ( +0,000%)	-189,3 ( -1,015%)
Cube decision rating	Supernatural	Awful!
Overall statistics
Error total EMG (MWC)	+0,000 ( +0,000%)	-0,196 ( -1,053%)
Error rate mEMG (MWC)	+0,0 ( +0,000%)	-65,5 ( -0,351%)
Snowie error rate	+0,0 ( +0,000%)	-49,1 ( +0,000%)
Overall rating	Supernatural	Awful!
Actual result	+4,67%	-4,67%
Luck adjusted result	+0,07%	-0,07%
Luck based FIBS rating diff.	+0,86
Error based abs. FIBS rating	2050,0	1855,9
Chequerplay errors rating loss	0,0	41,7
Cube errors rating loss	0,0	152,4

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Output generated Thu Sep 03 00:41:46 2009 by GNU Backgammon 0.90-mingw 20090615 (HTML Export version 1.214)