FIBS Board backgammon forum

We're ahead in the race by 16 pips, plus we've escaped our runners while he still has two back.  Big racing lead.

Our position is a bit better - a three point board, although we don't have the 5 point yet.  But the escaped runners count as a positional advantage, so clear advantage in position.

As for threats, we're threatening to make another homeboard point and if we can't do that, we'll just bring a couple of builders down and make a real threat.

Position, race and threats plus lots of market losers here, so ship it.

Hold. I don't like throwing the cube so recklessly when ahead 3-away/5-away. Also we have some gammon chances here. It should be very close though.

PL

I don't think we're being reckless here. An undoubled gammon doesn't win for us, but a doubled gammon does. Besides, do you really care if he takes and redoubles us ?

2-ply analysis says this is double-pass, and the holding the cube is a whopper.

0-ply rollout says it's too good to double, but that pushing the cube is a small error (.012)

When 2-ply analysis and 0-ply rollout disagree like this, it's time for a better rollout, so I hit it with 2-ply rollout. 2-ply rollout agrees with 0-ply rollout - too good to double, but by a small margin (.024)  Of course, if your cube play makes your opponent make a big error, who's to say that it's wrong?  It's a massive pass.




Cube analysis
2-ply cubeless equity  +0.786 (Money:  +0.681)
 0.730 0.276 0.009 - 0.270 0.061 0.002
Cubeful equities:
1. Double, pass         +1.000
2. Double, take         +1.108  ( +0.108)
3. No double            +0.906  ( -0.094)
Proper cube action: Double, pass


Rollout details:
Centered 1-cube:
 0.740 0.288 0.020 - 0.260 0.056 0.003 CL  +0.762 CF  +1.012
[0.001 0.003 0.002 - 0.001 0.001 0.000 CL   0.005 CF   0.010]
Player Zorba owns 2-cube:
 0.751 0.275 0.031 - 0.249 0.050 0.004 CL  +1.577 CF  +1.275
[0.002 0.003 0.003 - 0.002 0.001 0.001 CL   0.011 CF   0.014]
Full cubeful rollout with var.redn.
1296 games, Mersenne Twister dice gen. with seed 903967096 and quasi-random

dice
Play: 0-ply cubeful prune [expert]
Cube: 0-ply cubeful prune [expert]

1. Double, pass         +1.000  ( -0.012)
2. Double, take         +1.275  ( +0.263)
3. No double            +1.012  
Proper cube action: Too good to Double, pass



Rollout details:
Centered 1-cube:
 0.745 0.278 0.024 - 0.255 0.056 0.003 CL  +0.776 CF  +1.024
[0.001 0.003 0.002 - 0.001 0.001 0.001 CL   0.004 CF   0.008]
Player Zorba owns 2-cube:
 0.750 0.293 0.043 - 0.250 0.055 0.006 CL  +1.627 CF  +1.282
[0.001 0.004 0.004 - 0.001 0.001 0.001 CL   0.008 CF   0.012]
Full cubeful rollout with var.redn.
1296 games, Mersenne Twister dice gen. with seed 903967096 and quasi-random dice
Play:  2-ply cubeful prune [world class]
keep the first 0 0-ply moves and up to 8 more moves within equity 0.1
Skip pruning for 1-ply moves.
Cube: 2-ply cubeful prune [world class]

1. Double, pass         +1.000  ( -0.024)
2. Double, take         +1.282  ( +0.258)
3. No double            +1.024  
Proper cube action: Too good to Double, pass

courtesy of Neil Robins -

XG 3 ply rollout says its double/pass, not "too good".  The bots don't seem to agree on this one...



Analyzed in Rollout
No Double
Player Winning Chances:    74.95% (G: 25.53% B:  1.70%)
Opponent Winning Chances:  25.05% (G:  4.87% B:  0.24%)
Double/Take
Player Winning Chances:    75.06% (G: 28.83% B:  4.08%)
Opponent Winning Chances:  24.94% (G:  4.98% B:  0.37%)

Cubeless Equities: No Double=+0.779, Double=+1.527

Cubeful Equities:
      No Double:   +0.945 (-0.055)
      Double/Take: +1.159 (+0.159)
      Double/Drop: +1.000

Best Cube action: Double / Drop

Rollout
1298 Games rolled with Variance Reduction.
Dice Seed: 31247
First 2 moves and cube decisions: 4 ply
Remaining moves and cube decisions: 3 ply
Confidence No Double: ± 0.013 (+0.932<E<+0.958)
Confidence Double:    ± 0.021 (+1.138<E<+1.181)

Double Decision confidence: 100.0%
Take Decision confidence: 100.0%

Duration: 16 minutes 02 seconds

eXtreme Gammon Version: 1.21, MET: Rockwell-Kazaross