Hit or rip?

[Timothy Chow]

XGID=-EEaCB-----------bacbcab--:1:-1:1:21:0:0:0:0:10

Score is X:0 O:0. Unlimited Game
+13-14-15-16-17-18------19-20-21-22-23-24-+
| O O | | O O O O O | +---+
| O | | O O O O | | 2 |
| | | O O | +---+
| | | |
| | | |
| |BAR| |
| | | X X |
| | | X X |
| | | X X X |
| | | X X X X |
| | | X X O X X |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 37 O: 92 X-O: 0-0
Cube: 2, O own cube
X to play 21

---
Tim Chow

[ah....Clem]

I'll hit here. It keeps X even ended, it gets her our of our hair if she
rolls a six, and putting her on the roof seems to win more gammons than
ripping two since there are 16 dancing rolls that allow us to (usually)
take two off and be better off than ripping two now.

4/3*/1.

--
Ah....Clem
The future is fun, the future is fair.

[Timothy Chow]

Gammon wins are negligible here, and of course the win is in the bag
if X isn't hit. In such situations, hitting is often the wrong strategy
because it allows O to hang around longer for a shot. But here, O has
enough timing to hang around anyway if X doesn't hit, and hitting gives
O a chance to roll a 6 and (except for 63) be forced to disengage.

For comparison, see the variant, where it's a mistake to hit.

1. Rollout¹ 4/3* 3/1 eq:+0.874
Player: 93.81% (G:1.50% B:0.00%)
Opponent: 6.19% (G:0.01% B:0.00%)
Confidence: ±0.001 (+0.873..+0.875) - [100.0%]

2. Rollout¹ 4/2 1/Off eq:+0.810 (-0.064)
Player: 91.25% (G:1.20% B:0.00%)
Opponent: 8.75% (G:0.00% B:0.00%)
Confidence: ±0.001 (+0.808..+0.811) - [0.0%]

3. Rollout¹ 2/Off 1/Off eq:+0.794 (-0.080)
Player: 90.43% (G:2.70% B:0.01%)
Opponent: 9.57% (G:0.00% B:0.00%)
Confidence: ±0.002 (+0.791..+0.796) - [0.0%]

4. Rollout¹ 4/1 eq:+0.793 (-0.081)
Player: 90.51% (G:0.55% B:0.00%)
Opponent: 9.49% (G:0.01% B:0.00%)
Confidence: ±0.002 (+0.791..+0.795) - [0.0%]

5. Rollout¹ 2/1 2/Off eq:+0.761 (-0.112)
Player: 89.38% (G:1.43% B:0.00%)
Opponent: 10.62% (G:0.00% B:0.00%)
Confidence: ±0.003 (+0.758..+0.764) - [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
-------

XGID=-DDaCBB----------bacbcab--:1:-1:1:21:0:0:0:0:10

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

Pip count X: 46 O: 92 X-O: 0-0

Cube: 2, O own cube
X to play 21

1. Rollout¹ 2/Off 1/Off eq:+0.840
Player: 92.23% (G:2.61% B:0.01%)
Opponent: 7.77% (G:0.00% B:0.00%)
Confidence: ±0.002 (+0.838..+0.842) - [100.0%]

2. Rollout¹ 6/5 6/4 eq:+0.835 (-0.005)
Player: 92.24% (G:1.70% B:0.00%)
Opponent: 7.76% (G:0.00% B:0.00%)
Confidence: ±0.002 (+0.833..+0.837) - [0.0%]

3. Rollout¹ 2/1 2/Off eq:+0.804 (-0.036)
Player: 90.95% (G:1.64% B:0.00%)
Opponent: 9.05% (G:0.00% B:0.00%)
Confidence: ±0.002 (+0.802..+0.806) - [0.0%]

4. Rollout¹ 4/3* 3/1 eq:+0.775 (-0.066)
Player: 89.31% (G:2.04% B:0.00%)
Opponent: 10.69% (G:0.07% B:0.00%)
Confidence: ±0.002 (+0.773..+0.777) - [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

---
Tim Chow