Money game: X to play 1-4 from the bar

[tc...@lsa.umich.edu]

X is in trouble here and has to make the best of a bad situation. What
is your play? Over the board, I made the wrong decision.

GNU Backgammon Position ID: mLuDAwSw1+AAVA
+24-23-22-21-20-19------18-17-16-15-14-13-+ O: gnubg
| X X O O | | O O X | 0 points
| O O | | O O X |
| O | | O O X |
| | | |
| | | |
| |BAR| |v (Cube: 1)
| | | |
| X | | |
| X | | O |
| X X | | X O | Rolled 14
| O X X | X | X X O | 0 points
+-1--2--3--4--5--6-------7--8--9-10-11-12-+ X: tchow
--
Tim Chow tchow-at-alum-dot-mit-dot-edu
The range of our projectiles---even ... the artillery---however great, will
never exceed four of those miles of which as many thousand separate us from
the center of the earth. ---Galileo, Dialogues Concerning Two New Sciences

[Piranha]

No choice about the 1, so the only problem is, what to do with the 4.
I´d hit, 8/4.
Behind already, having an anchor in the 1, I don´t care to fall
further behind, so either I get away with an aggressive hit, or I try
for a backgame.

Not sure about odds against a bot, but against a real opponent,
depending on his skills, theres a good chance he might not dare cubing
against a huge backgame, but without the hit upon any other move, he
might cube right there, and I guess that would be a pass.

[N Merrigan]

The key to this position is O's 5-pt. Bold vs aggressive play I'll leave
for the birds. If O makes the 5 then its a casual hop, skip and a jump home
like a hippy with carefree in his hair. X must get there first.

8/4*.

N.Merrigan
<tc...@lsa.umich.edu> wrote in message
news:4b2ad3bb$0$502$b45e...@senator-bedfellow.mit.edu...

[David C. Ullrich]

On 18 Dec 2009 00:58:35 GMT, tc...@lsa.umich.edu wrote:

>X is in trouble here and has to make the best of a bad situation. What
>is your play? Over the board, I made the wrong decision.

Then you must not have hit. Because, as is well known,
it's never wrong to hit.

> GNU Backgammon Position ID: mLuDAwSw1+AAVA
> +24-23-22-21-20-19------18-17-16-15-14-13-+ O: gnubg
> | X X O O | | O O X | 0 points
> | O O | | O O X |
> | O | | O O X |
> | | | |
> | | | |
> | |BAR| |v (Cube: 1)
> | | | |
> | X | | |
> | X | | O |
> | X X | | X O | Rolled 14
> | O X X | X | X X O | 0 points
> +-1--2--3--4--5--6-------7--8--9-10-11-12-+ X: tchow

David C. Ullrich

"Understanding Godel isn't about following his formal proof.
That would make a mockery of everything Godel was up to."
(John Jones, "My talk about Godel to the post-grads."
in sci.logic.)

[tc...@lsa.umich.edu]

In article <mb6ni5hl2pldkskfi...@4ax.com>,

David C. Ullrich <dull...@sprynet.com> wrote:
>Then you must not have hit. Because, as is well known,
>it's never wrong to hit.

You are correct! I incorrectly reasoned that I didn't want another checker
sent back, so I played bar/24 7/3. But the usual safe-vs.-bold criteria
suggest a bold play, and this is no exception. The hit is right not only
because it gives O bad rolls (dancing), but because X needs the tempo. If
X does get hit back, not all is lost because O has only a two-point board
and X has decent chances of anchoring on the 20-point or 22-point, with a
playable holding game.

In fact bar/24 8/4* is the only play that allows X to take the cube. I did
the rollout slightly unconventionally here, rolling out O's cube decision
after each of three possible plays by X, so that you can see how big the
drop is. Each rollout was a 1296-game supremo rollout.

>> GNU Backgammon Position ID: mLuDAwSw1+AAVA
>> +24-23-22-21-20-19------18-17-16-15-14-13-+ O: gnubg
>> | X X O O | | O O X | 0 points
>> | O O | | O O X |
>> | O | | O O X |
>> | | | |
>> | | | |
>> | |BAR| |v (Cube: 1)
>> | | | |
>> | X | | |
>> | X | | O |
>> | X X | | X O | Rolled 14
>> | O X X | X | X X O | 0 points
>> +-1--2--3--4--5--6-------7--8--9-10-11-12-+ X: tchow

After bar/24 8/4*:
Centered 1-cube:
0.680 0.279 0.034 - 0.320 0.066 0.002 CL +0.604 CF +0.835
[0.002 0.002 0.001 - 0.002 0.001 0.000 CL 0.005 CF 0.013]
Player tchow owns 2-cube:
0.675 0.298 0.041 - 0.325 0.066 0.003 CL +1.243 CF +0.949
[0.003 0.003 0.002 - 0.003 0.001 0.000 CL 0.017 CF 0.022]

After bar/20:
Centered 1-cube:
0.717 0.243 0.015 - 0.283 0.054 0.001 CL +0.637 CF +0.877
[0.001 0.002 0.001 - 0.001 0.001 0.000 CL 0.003 CF 0.008]
Player tchow owns 2-cube:
0.703 0.299 0.026 - 0.297 0.057 0.002 CL +1.345 CF +1.108
[0.002 0.002 0.001 - 0.002 0.001 0.000 CL 0.011 CF 0.015]

After bar/24 7/3:
Centered 1-cube:
0.742 0.214 0.016 - 0.258 0.054 0.001 CL +0.659 CF +0.922
[0.001 0.001 0.001 - 0.001 0.001 0.000 CL 0.003 CF 0.007]
Player tchow owns 2-cube:
0.750 0.213 0.017 - 0.250 0.044 0.001 CL +1.371 CF +1.169
[0.002 0.002 0.001 - 0.002 0.001 0.000 CL 0.009 CF 0.012]