Discussion:
Followup to previous problem
(too old to reply)
Tim Chow
2020-06-23 14:12:16 UTC
Permalink
Here you can see what I played OTB in the "Either 5pt beats either 4pt"
problem. Now what?


XGID=---a-BCCAA--cB----bdBb-cA-:1:1:1:41:0:0:0:0:10

X:Player 1 O:Player 2
Score is X:0 O:0. Unlimited Game
+13-14-15-16-17-18------19-20-21-22-23-24-+
| X O | | O X O O X |
| X O | | O X O O |
| | | O O |
| | | O |
| | | |
| |BAR| |
| | | |
| | | |
| O X | | X | +---+
| O X | | X X | | 2 |
| O X X X | | X X O | +---+
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 156 O: 113 X-O: 0-0
Cube: 2, X own cube
X to play 41

---
Tim Chow
Peter
2020-06-23 16:16:45 UTC
Permalink
Post by Tim Chow
Here you can see what I played OTB in the "Either 5pt beats either 4pt"
problem. Now what?
XGID=---a-BCCAA--cB----bdBb-cA-:1:1:1:41:0:0:0:0:10
X:Player 1 O:Player 2
Score is X:0 O:0. Unlimited Game
+13-14-15-16-17-18------19-20-21-22-23-24-+
| X O | | O X O O X |
| X O | | O X O O |
| | | O O |
| | | O |
| | | |
| |BAR| |
| | | |
| | | |
| O X | | X | +---+
| O X | | X X | | 2 |
| O X X X | | X X O | +---+
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 156 O: 113 X-O: 0-0
Cube: 2, X own cube
X to play 41
---
Tim Chow
If I were me, I'd play 9/8 24/20. Otherwise I'd hit.
b***@gmail.com
2020-06-25 22:02:41 UTC
Permalink
Post by Peter
Post by Tim Chow
Here you can see what I played OTB in the "Either 5pt beats either 4pt"
problem. Now what?
XGID=---a-BCCAA--cB----bdBb-cA-:1:1:1:41:0:0:0:0:10
X:Player 1 O:Player 2
Score is X:0 O:0. Unlimited Game
+13-14-15-16-17-18------19-20-21-22-23-24-+
| X O | | O X O O X |
| X O | | O X O O |
| | | O O |
| | | O |
| | | |
| |BAR| |
| | | |
| | | |
| O X | | X | +---+
| O X | | X X | | 2 |
| O X X X | | X X O | +---+
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 156 O: 113 X-O: 0-0
Cube: 2, X own cube
X to play 41
---
Tim Chow
If I were me, I'd play 9/8 24/20. Otherwise I'd hit.
Just be yourself.

Stick
Tim Chow
2020-06-26 14:19:20 UTC
Permalink
XGID=---a-BCCAA--cB----bdBb-cA-:1:1:1:41:0:0:0:0:10

X:Player 1 O:Player 2
Score is X:0 O:0. Unlimited Game
+13-14-15-16-17-18------19-20-21-22-23-24-+
| X O | | O X O O X |
| X O | | O X O O |
| | | O O |
| | | O |
| | | |
| |BAR| |
| | | |
| | | |
| O X | | X | +---+
| O X | | X X | | 2 |
| O X X X | | X X O | +---+
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 156 O: 113 X-O: 0-0
Cube: 2, X own cube
X to play 41

Although it's not as clear an example as BlueDice's recent position, this
position also illustrates how keeping your last checker back "for more
contact" isn't necessarily the right idea even when you're far behind in
the pip count. Keeping the straggler back may increase your chances of
sending another of your opponent's checkers back, but it can also be a
liability, and stepping it up can help with containing your opponent's
straggler.

As for hitting, it's not very effective here. X is trying to contain,
not blitz. To give some sense for the tradeoff---XG says that getting hit
back with 32 or 21 after 9/8 7/3* is about as bad for X as having O roll
a 62 after 24/20 9/8.

1. Rollout¹ 24/20 9/8 eq:+0.203
Player: 49.73% (G:9.51% B:0.32%)
Opponent: 50.27% (G:10.06% B:0.14%)
Confidence: ±0.010 (+0.193..+0.212) - [100.0%]

2. Rollout¹ 9/8 7/3* eq:+0.088 (-0.114)
Player: 48.75% (G:11.22% B:0.44%)
Opponent: 51.25% (G:19.98% B:0.63%)
Confidence: ±0.011 (+0.077..+0.099) - [0.0%]

¹ 1296 Games rolled with Variance Reduction.
Dice Seed: 271828
Moves: 3-ply, cube decisions: XG Roller

eXtreme Gammon Version: 2.19.207.pre-release

---
Tim Chow
b***@gmail.com
2020-06-26 15:39:46 UTC
Permalink
Post by Tim Chow
XGID=---a-BCCAA--cB----bdBb-cA-:1:1:1:41:0:0:0:0:10
X:Player 1 O:Player 2
Score is X:0 O:0. Unlimited Game
+13-14-15-16-17-18------19-20-21-22-23-24-+
| X O | | O X O O X |
| X O | | O X O O |
| | | O O |
| | | O |
| | | |
| |BAR| |
| | | |
| | | |
| O X | | X | +---+
| O X | | X X | | 2 |
| O X X X | | X X O | +---+
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 156 O: 113 X-O: 0-0
Cube: 2, X own cube
X to play 41
Although it's not as clear an example as BlueDice's recent position, this
position also illustrates how keeping your last checker back "for more
contact" isn't necessarily the right idea even when you're far behind in
the pip count. Keeping the straggler back may increase your chances of
sending another of your opponent's checkers back, but it can also be a
liability, and stepping it up can help with containing your opponent's
straggler.
As for hitting, it's not very effective here. X is trying to contain,
not blitz. To give some sense for the tradeoff---XG says that getting hit
back with 32 or 21 after 9/8 7/3* is about as bad for X as having O roll
a 62 after 24/20 9/8.
1. Rollout¹ 24/20 9/8 eq:+0.203
Player: 49.73% (G:9.51% B:0.32%)
Opponent: 50.27% (G:10.06% B:0.14%)
Confidence: ±0.010 (+0.193..+0.212) - [100.0%]
2. Rollout¹ 9/8 7/3* eq:+0.088 (-0.114)
Player: 48.75% (G:11.22% B:0.44%)
Opponent: 51.25% (G:19.98% B:0.63%)
Confidence: ±0.011 (+0.077..+0.099) - [0.0%]
¹ 1296 Games rolled with Variance Reduction.
Dice Seed: 271828
Moves: 3-ply, cube decisions: XG Roller
eXtreme Gammon Version: 2.19.207.pre-release
---
Tim Chow
It's pretty clear regardless of the race that you don't keep a rear guard/last man back when he can step up to an anchor posed for coverage/escaping when the opponent has mainly filled in the points between your anchor and that back man.

Stick

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