Glad to see I'm not the only one to find this decision difficult. First I'll give the rollout and then I'll give some analysis.
           
 
        
 | | White is Player 2
score: 0
pip: 116 | Money session
Jacoby | pip: 124
score: 0
Blue is Player 1 |
|
| XGID=--BABbB-D----BA-cabb-bb-aA:0:0:1:23:0:0:1:0:10 |
| Blue to play 23 |
| 1. | Rollout1 | Bar/23 14/11 | eq: -0.676 |
| Player:
Opponent: | 36.20% (G:7.37% B:0.44%)
63.80% (G:28.00% B:0.59%) | Conf: ± 0.017 (-0.693...-0.659)
Duration: 2 hours 00 minute |
|
| 2. | Rollout1 | Bar/20 | eq: -0.750 (-0.074) |
| Player:
Opponent: | 35.73% (G:6.25% B:0.32%)
64.27% (G:28.97% B:0.66%) | Conf: ± 0.015 (-0.765...-0.735)
Duration: 2 hours 06 minutes |
|
| |
1 2592 Games rolled with Variance Reduction.
Moves and cube decisions: 3 ply
|
eXtreme Gammon Version: 1.21
I think there are two key points to understanding this position. The first point is that White's attack is very strong and Blue's straggler is considerably safer when tucked away on the 23pt. After either bar/20 or bar/23 14/11, XG 3-ply correctly realizes that White has a huge cube. If White's position were slightly stronger—say White's 9pt spare were on White's 6pt instead—then Blue would probably have to pass. Note also that if we move that spare to White's 3pt then stepping up is probably correct because the 23pt is no longer as safe a haven (I'm going to rely on XGR+ here, which qualitatively agrees with the rollout of the original position):
| | White is Player 2
score: 0
pip: 110 | Money session
Jacoby | pip: 124
score: 0
Blue is Player 1 |
|
| XGID=--BABbB-D----BA-babb-bc-aA:0:0:1:23:0:0:1:0:10 |
| Blue to play 23 |
| 1. | XG Roller+ | Bar/20 | eq: -0.764 |
| Player:
Opponent: | 36.23% (G:6.78% B:0.32%)
63.77% (G:28.21% B:0.52%) | |
|
| 2. | XG Roller+ | Bar/23 14/11 | eq: -0.823 (-0.059) |
| Player:
Opponent: | 35.04% (G:7.71% B:0.41%)
64.96% (G:29.78% B:0.60%) | |
|
eXtreme Gammon Version: 1.21
The second point to note is that playing 14/11 and converting White's indirect shot into a direct shot is not as dangerous as it might seem at first glance. Although Blue would prefer to not move at all than to play the 3, it is apparently less dangerous to play 14/11 than to step up with 23/20. White has almost no hit-and-cover or double-hitting numbers. If we move Blue's 14pt checker to the 12pt then hanging back on the 23pt still seems right, though if we lift the 14pt blot to the 13pt then stepping up seems preferable to exposing a second blot:
| | White is Player 2
score: 0
pip: 116 | Money session
Jacoby | pip: 122
score: 0
Blue is Player 1 |
|
| XGID=--BABbB-D---AB--cabb-bb-aA:0:0:1:23:0:0:1:0:10 |
| Blue to play 23 |
| 1. | XG Roller+ | Bar/23 12/9 | eq: -0.565 |
| Player:
Opponent: | 37.37% (G:7.90% B:0.38%)
62.63% (G:23.59% B:0.60%) | |
|
| 2. | XG Roller+ | Bar/20 | eq: -0.689 (-0.123) |
| Player:
Opponent: | 36.91% (G:7.76% B:0.39%)
63.09% (G:27.90% B:0.65%) | |
|
eXtreme Gammon Version: 1.21
| | White is Player 2
score: 0
pip: 116 | Money session
Jacoby | pip: 123
score: 0
Blue is Player 1 |
|
| XGID=--BABbB-D----C--cabb-bb-aA:0:0:1:23:0:0:1:0:10 |
| Blue to play 23 |
| 1. | XG Roller+ | Bar/20 | eq: -0.519 |
| Player:
Opponent: | 38.25% (G:6.37% B:0.26%)
61.75% (G:22.51% B:0.30%) | |
|
| 2. | XG Roller+ | Bar/23 13/10 | eq: -0.599 (-0.081) |
| Player:
Opponent: | 37.32% (G:7.66% B:0.37%)
62.68% (G:24.28% B:0.58%) | |
|
eXtreme Gammon Version: 1.21
Finally, let's take a look at my decision on the preceding roll. This seems to me to be further confirmation that 14/11 isn't as dangerous as it looks; XGR+ prefers it to the safe-looking but somewhat destructive 6/3 that I played.
| | White is gnubg
score: 4
pip: 122 | | 7 point match | pip: 127
score: 0
Blue is tchow |
|
| XGID=--B-BbC-D----BA-cbbc--b-aA:0:0:1:43:0:4:0:7:10 |
| Blue to play 43 |
| 1. | XG Roller+ | Bar/21 14/11 | eq: -0.227 |
| Player:
Opponent: | 41.37% (G:6.48% B:0.26%)
58.63% (G:17.80% B:0.31%) | |
|
| 2. | XG Roller+ | Bar/21 6/3 | eq: -0.255 (-0.029) |
| Player:
Opponent: | 41.27% (G:5.68% B:0.23%)
58.73% (G:18.74% B:0.42%) | |
|
eXtreme Gammon Version: 1.21, MET: Rockwell-Kazaross