Gammonfever BG Quiz - Position #11/12 (2 in one position)

Micke Nilsson

unread,

Sep 25, 2005, 5:20:02 AM9/25/05

to

Here's another 2-in-1 position. O is on roll:

A) Double or no double for O from the bar?
B) If O dances, what should O do when X doubles?

Money session. Score X-O: 0-0

O on roll, cube action
+-1--2--3--4--5--6--------7--8--9-10-11-12-+
| O O O | | O X O X |
| O O O | | O O X |
| O | | | S
| O | | | n
| | | | o
| |BAR| | w
| X | O | | i
| X | | | e
| X | | |
| X X X | | O |
| X X X X | | X X O |
+24-23-22-21-20-19-------18-17-16-15-14-13-+
Pipcount X: 99 O: 129 X-O: 0-0/Money (1)
CubeValue: 1

jckz

unread,

Sep 25, 2005, 7:04:06 AM9/25/05

to

A) No double. 9 numbers don't enter, only 5 numbers hit, and X is way
ahead in the race.

B) Pass. X will probably make one more point in his home board next
turn, and is ahead in the race.

paulde...@att.net

unread,

Sep 25, 2005, 7:29:12 AM9/25/05

to

A) I don't understand jckz saying "only 5 numbers hit". I counted 20
hitting numbers. But jckz is right that it's no double. The hits are
not devastating and X is well ahead in the race if 0 misses and
slightly ahead if 0 hits. If 0 blunders and doubles, X should not
beaver.

B) I agree with jckz that 0 passes in this scenario. Even if X fails
to make another point, X can safety the blot on the 3 point. Then X
wins the race when 0 enters. X doesn't have enough contact
possibilities to justify a take.

Paul Epstein

David C. Ullrich

unread,

Sep 25, 2005, 9:55:41 AM9/25/05

to

On 25 Sep 2005 04:29:12 -0700, paulde...@att.net wrote:

>A) I don't understand jckz saying "only 5 numbers hit". I counted 20
>hitting numbers. But jckz is right that it's no double. The hits are
>not devastating and X is well ahead in the race if 0 misses and
>slightly ahead if 0 hits. If 0 blunders and doubles, X should not
>beaver.
>
>B) I agree with jckz that 0 passes in this scenario. Even if X fails
>to make another point, X can safety the blot on the 3 point. Then X
>wins the race when 0 enters. X doesn't have enough contact
>possibilities to justify a take.

Assuming that the last sentence was a typo, this all seems
right to me. Actually this seems like the easiest one so far.

(But what do we know?)

>Paul Epstein
>
>
>
>
>jckz wrote:
>> A) No double. 9 numbers don't enter, only 5 numbers hit, and X is way
>> ahead in the race.
>>
>> B) Pass. X will probably make one more point in his home board next
>> turn, and is ahead in the race.

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

David C. Ullrich

jckz

unread,

Sep 25, 2005, 10:32:44 AM9/25/05

to

Sorry for miscounting...

paulde...@att.net

unread,

Sep 25, 2005, 10:47:56 AM9/25/05

to

Yes, sorry about the typo. I meant that 0 doesn't have enough contact
possibilities to justify a take (scenario B).

Paul

Grunty

unread,

Sep 25, 2005, 12:51:04 PM9/25/05

to

A) No double.
20 hits and many blots around, but O's board is only 3 points.
The sequence O hits - X dances does not occur as much as to guarantee O
enough gammons.
Plus, the immediate 25% chance of staying on the bar.

B) That 25% are *big* cashes for X.

C) We can add a third question, making it problem 12bis:
If O doubled and then danced, it's not obvious at all that X should
redouble -- should X play on for a gammon instead ?

paulde...@att.net

unread,

Sep 25, 2005, 1:46:07 PM9/25/05

to

Grunty,

X is nowhere near good enough to play on for a gammon. The number of
losses for X are far more than 1/2 X's gammons and there are lots of
ways for X to lose if X plays on. Playing on for the gammon is a huge
blunder.

Even if X achieves the closeout without 0 moving at all (surely a great
deal to hope for), 0 retains significant gammon-saving chances.

Paul Epstein

Micke Nilsson

unread,

Sep 25, 2005, 3:56:36 PM9/25/05

to

For the first time so far nobody agrees with Snowie in this position. You
all got A right, but it's not a huge error to double here. The rollout shows
that double/take is only -0,005 compared to a hold.

A:

3-ply instant evaluation:

Money session. Score X-O: 0-0

O on roll, cube action
+-1--2--3--4--5--6--------7--8--9-10-11-12-+
| O O O | | O X O X |
| O O O | | O O X |
| O | | | S
| O | | | n
| | | | o
| |BAR| | w
| X | O | | i
| X | | | e
| X | | |
| X X X | | O |
| X X X X | | X X O |
+24-23-22-21-20-19-------18-17-16-15-14-13-+
Pipcount X: 99 O: 129 X-O: 0-0/Money (1)
CubeValue: 1

3-Ply Money equity: 0,216
1,1% 21,7% 55,7% 44,3% 12,1% 0,3%
1. No double 0,171
2. Double, take 0,107 (-0,064)
3. Double, pass 1,000 (+0,829)
Proper cube action: No double, take 7%

------------------------------ End ----------------------------------

3-ply rollout:

Money session. Score X-O: 0-0

O on roll, cube action
+-1--2--3--4--5--6--------7--8--9-10-11-12-+
| O O O | | O X O X |
| O O O | | O O X |
| O | | | S
| O | | | n
| | | | o
| |BAR| | w
| X | O | | i
| X | | | e
| X | | |
| X X X | | O |
| X X X X | | X X O |
+24-23-22-21-20-19-------18-17-16-15-14-13-+
Pipcount X: 99 O: 129 X-O: 0-0/Money (1)
CubeValue: 1

Rollout Money equity: 0,218
1,4% 21,6% 55,4% 44,6% 11,8% 0,3%
95% confidence interval:
- money cubeless eq.: 0,218 ą0,024,
- live cube no double: 0,179 ą0,044,
- live cube double take: 0,174 ą0,066.
Rollout settings:
Full rollout,
324 games (equiv. 13764 games),
played 3-ply (standard), cube 3-ply,
settlement 0,550 at 16 pts,
seed 1, without race database.
Evaluations
1. No double 0,171
2. Double, take 0,108 (-0,063)
3. Double, pass 1,000 (+0,829)
Proper cube action: No double, take 7%
Live cube
1. No double 0,179
2. Double, take 0,174 (-0,005)
3. Double, pass 1,000 (+0,821)
Proper cube action: No double, take 1%

------------------------------ End ----------------------------------

Micke Nilsson

unread,

Sep 25, 2005, 3:58:22 PM9/25/05

to

When it comes to B, the drop you all think is obvious is actually a pretty
big blunder...

3-ply instant evaluation:

Money session. Score X-O: 0-0

X on roll, cube action
+24-23-22-21-20-19-------18-17-16-15-14-13-+

| O O O | | O X O X |
| O O O | | O O X |
| O | | | S
| O | | | n
| | | | o
| |BAR| | w
| X | O | | i
| X | | | e
| X | | |
| X X X | | O |
| X X X X | | X X O |

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

Pipcount X: 99 O: 129 X-O: 0-0/Money (1)
CubeValue: 1

3-Ply Money equity: 0,459
0,4% 19,3% 66,5% 33,5% 6,5% 0,2%
1. Double, take 0,675
2. No double 0,626 (-0,048)
3. Double, pass 1,000 (+0,325)
Proper cube action: Double, take

------------------------------ End ----------------------------------

3-ply rollout:

Money session. Score X-O: 0-0

X on roll, cube action
+24-23-22-21-20-19-------18-17-16-15-14-13-+

| O O O | | O X O X |
| O O O | | O O X |
| O | | | S
| O | | | n
| | | | o
| |BAR| | w
| X | O | | i
| X | | | e
| X | | |
| X X X | | O |
| X X X X | | X X O |

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

Pipcount X: 99 O: 129 X-O: 0-0/Money (1)
CubeValue: 1

Rollout Money equity: 0,505
0,2% 19,0% 68,8% 31,2% 6,0% 0,2%
95% confidence interval:
- money cubeless eq.: 0,505 ą0,018,
- live cube no double: 0,652 ą0,026,
- live cube double take: 0,797 ą0,046.
Rollout settings:
Full rollout,
324 games (equiv. 14381 games),

played 3-ply (standard), cube 3-ply,
settlement 0,550 at 16 pts,
seed 1, without race database.
Evaluations

1. Double, take 0,783
2. No double 0,663 (-0,121)
3. Double, pass 1,000 (+0,217)
Proper cube action: Double, take
Live cube
1. Double, take 0,797
2. No double 0,652 (-0,144)
3. Double, pass 1,000 (+0,203)
Proper cube action: Double, take

------------------------------ End ----------------------------------

paulde...@att.net

unread,

Sep 25, 2005, 4:03:29 PM9/25/05

to

Not to be too defensive but jckz and I never suggested the drop in B
was "obvious". So I'd argue with "you all..."
I am surprised, though.

Paul Epstein

Micke Nilsson

unread,

Sep 25, 2005, 5:11:36 PM9/25/05

to

Sorry, obvious was not a correct description. What I meant was that nobody
said it was a marginal drop or a possible take. I was surprised myself. I am
sure I would have dropped this at the table.

/Micke

<paulde...@att.net> skrev i meddelandet
news:1127678609.4...@g47g2000cwa.googlegroups.com...