Hit or play safe? 2

[Timothy Chow]

XGID=--aB--DaB---bD---b-e-bB-bA:0:0:1:21:0:0:0:0:10

Score is X:0 O:0. Unlimited Game
+13-14-15-16-17-18------19-20-21-22-23-24-+
| X O | | O O X O |
| X O | | O O X O |
| X | | O |
| X | | O |
| | X | O |
| |BAR| |
| | | |
| | | X |
| | | X |
| O X | | X X |
| O X O | | X X O |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 167 O: 123 X-O: 0-0
Cube: 1
X to play 21

---
Tim Chow

[Robert Zimmerman]

My first inclination was to hit despite seeing that almost 2/3 of Os rolls will hit or make an advanced anchor. Not hitting looked too resigned. But looking at Os rolls after playing the quiet bar/22 reveals a pretty rough position for O. 6s, 3s and 1s stink for O. I'd play safe.

Bob

[Timothy Chow]

Backgammon adages often contradict each other. Magriel's criteria tell
us to note that X has more checkers back and is anchored while O is not.
That might seem to suggest a bold play, such as hitting or slotting the
5pt. But Joe Sylvester famously said, "When defending, make defensive
plays."

The trouble with hitting here is that there's not too much upside to be
had. O has only four dancing rolls, and not very many other bad rolls.
O has no immediate threat that demands a tempo hit.

In Variant 1 below, X has a spare on his 8pt to hit with. In Variant 2,
O has slotted her 5pt, which incentivizes X to hit for tempo.

1. Rollout¹ Bar/22 eq:-0.319
Player: 42.94% (G:10.28% B:0.44%)
Opponent: 57.06% (G:19.11% B:0.47%)
Confidence: ±0.014 (-0.333..-0.305) - [100.0%]

2. Rollout¹ Bar/23 6/5 eq:-0.455 (-0.136)
Player: 42.34% (G:9.82% B:0.46%)
Opponent: 57.66% (G:28.60% B:0.84%)
Confidence: ±0.016 (-0.471..-0.439) - [0.0%]

3. Rollout¹ Bar/23 8/7* eq:-0.464 (-0.145)
Player: 42.17% (G:10.60% B:0.49%)
Opponent: 57.83% (G:30.14% B:1.15%)
Confidence: ±0.013 (-0.477..-0.452) - [0.0%]

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

eXtreme Gammon Version: 2.19.211.pre-release

---------
Variant 1
---------

XGID=--aB--DaC---bC---b-e-bB-bA:0:0:1:21:0:0:0:0:10

Score is X:0 O:0. Unlimited Game
+13-14-15-16-17-18------19-20-21-22-23-24-+
| X O | | O O X O |
| X O | | O O X O |
| X | | O |

| | | O |
| | X | O |
| |BAR| |
| | | |
| | | X |
| X | | X |
| O X | | X X |
| O X O | | X X O |
+12-11-10--9--8--7-------6--5--4--3--2--1-+

Pip count X: 162 O: 123 X-O: 0-0

Cube: 1
X to play 21

1. Rollout¹ Bar/23 8/7* eq:-0.216
Player: 46.41% (G:13.29% B:0.59%)
Opponent: 53.59% (G:22.48% B:0.78%)
Confidence: ±0.017 (-0.233..-0.199) - [100.0%]

2. Rollout¹ Bar/22 eq:-0.274 (-0.058)
Player: 43.52% (G:10.99% B:0.40%)
Opponent: 56.48% (G:16.88% B:0.40%)
Confidence: ±0.014 (-0.288..-0.261) - [0.0%]

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

eXtreme Gammon Version: 2.19.211.pre-release

---------
Variant 2
---------

XGID=--aB--DaB---cD---b-cabB-bA:0:0:1:21:0:0:0:0:10

Score is X:0 O:0. Unlimited Game
+13-14-15-16-17-18------19-20-21-22-23-24-+

| X O | | O O O X O |

| X O | | O O X O |
| X | | O |
| X | | |

| | X | |
| |BAR| |

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

Pip count X: 167 O: 129 X-O: 0-0

Cube: 1
X to play 21

1. Rollout¹ Bar/23 8/7* eq:-0.452
Player: 41.22% (G:11.13% B:0.53%)
Opponent: 58.78% (G:26.88% B:1.05%)
Confidence: ±0.012 (-0.464..-0.441) - [97.9%]

2. Rollout¹ Bar/22 eq:-0.469 (-0.016)
Player: 38.89% (G:9.66% B:0.40%)
Opponent: 61.11% (G:19.04% B:0.52%)
Confidence: ±0.011 (-0.479..-0.458) - [2.1%]

3. Rollout¹ Bar/23 6/5 eq:-0.483 (-0.031)
Player: 40.85% (G:10.87% B:0.52%)
Opponent: 59.15% (G:27.41% B:0.85%)
Confidence: ±0.011 (-0.494..-0.473) - [0.0%]

¹ 2592 Games rolled with Variance Reduction.
Dice Seed: 271828
Moves: 3-ply, cube decisions: XG Roller

eXtreme Gammon Version: 2.19.211.pre-release

---
Tim Chow