Basic doubling position, one checker behind

[blitzxz]

Doubling is usually well played in holding games but what about when there is only one checker behind. Black on roll. Answer in spoiler.

Score is 0-0 (5 point match). Pip count: Black 123, White 135.

Spoiler

There is three important things in this kind of positions. Prime & number of points, distribution of checkers and of course race.

Weak side can usully take in normal 10 % down racing lead or so but if the distribution is good for leader or there is any kind of prime (for example three points together) then it is a pass. Or vica verse if the race is even then with good distribution or prime, leader still might just have a double but it's clear take.

Cube analysis
Rollout cubeless equity  +0,641 (Money:  +0,636)

Cubeful equities:
1. Double, pass         +1,000
2. Double, take         +1,188  ( +0,188)
3. No double            +0,945  ( -0,055)
Proper cube action: Double, pass
Rollout details:
Centered 1-cube:
  0,752 0,159 0,002 - 0,248 0,028 0,001 CL  +0,641 CF  +0,945
[0,001 0,002 0,000 - 0,001 0,001 0,001 CL   0,003 CF   0,007]
Player Trystman owns 2-cube:
  0,760 0,167 0,001 - 0,240 0,027 0,002 CL  +1,364 CF  +1,188
[0,002 0,003 0,000 - 0,002 0,001 0,001 CL   0,010 CF   0,013]
Full cubeful rollout with var.redn.
791 games, Mersenne Twister dice gen. with seed 825396884 and quasi-random dice
Play: 0-ply cubeful prune [expert]
Cube: 0-ply cubeful prune [expert]

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[PersianLord]

Doubling is usually well played in holding games but what about when there is only one checker behind. Black on roll. Answer in spoiler.

Score is 0-0 (5 point match). Pip count: Black 123, White 135.

Spoiler

There is three important things in this kind of positions. Prime & number of points, distribution of checkers and of course race.

Weak side can usully take in normal 10 % down racing lead or so but if the distribution is good for leader or there is any kind of prime (for example three points together) then it is a pass. Or vica verse if the race is even then with good distribution or prime, leader still might just have a double but it's clear take.

Cube analysis
Rollout cubeless equity  +0,641 (Money:  +0,636)

Cubeful equities:
1. Double, pass         +1,000
2. Double, take         +1,188  ( +0,188)
3. No double            +0,945  ( -0,055)
Proper cube action: Double, pass
Rollout details:
Centered 1-cube:
  0,752 0,159 0,002 - 0,248 0,028 0,001 CL  +0,641 CF  +0,945
[0,001 0,002 0,000 - 0,001 0,001 0,001 CL   0,003 CF   0,007]
Player Trystman owns 2-cube:
  0,760 0,167 0,001 - 0,240 0,027 0,002 CL  +1,364 CF  +1,188
[0,002 0,003 0,000 - 0,002 0,001 0,001 CL   0,010 CF   0,013]
Full cubeful rollout with var.redn.
791 games, Mersenne Twister dice gen. with seed 825396884 and quasi-random dice
Play: 0-ply cubeful prune [expert]
Cube: 0-ply cubeful prune [expert]

[close]

Spoiler

I was the 1st voter, and the 1st sucker, lol. I thought that white may well escape black's onslaught and then there will be an even race. If black can't make a point next rolls, white will do a more normal bear-in and this might be of help, if white can run away. There are also rolls for black that would leave him with direct and indirect shots, like 6-5.Just my thoughts

By the way, would you plz provide us with 2-ply analysis?

[close]

[blitzxz]

Spoiler

6-5 is the only roll that gives any shots and even then black is just ok to hit loose. 6-3 is a hit and point. 6-2 from mid point and 5-2 is a new point. Majority of rolls makes new points for black. White to win black must roll couple bad rolls in row and then leave a shot or white could just run over black even though he is now 10 % behind and might get trapped. But this is just what happened in the actual game. White got his lucky shot after all and won the game. Gammons are also important here. Lot more then I thought.

2 ply rollout takes a while but sure.

[close]

[socksey]

Spoiler

I'm the dummy who voted double/pass.  Vici would yell at me because black has no 6 move and is 2 away.  I'd probably do it anyway.  The pass because of position.

[close]

socksey



The worst moment for an atheist is when he feels grateful and has no one to thank. -- Wendy Ward

[blitzxz]

Spoiler

Here is very short 2-ply rollout with narrow filter. Difference is clear with only 250 games and I don't have now time to make longer rollout.

Cube analysis
Rollout cubeless equity  +0,633 (Money:  +0,634)

Cubeful equities:
1. Double, pass         +1,000
2. Double, take         +1,169  ( +0,169)
3. No double            +0,940  ( -0,060)
Proper cube action: Double, pass
Rollout details:
Centered 1-cube:
  0,747 0,174 0,002 - 0,253 0,035 0,001 CL  +0,633 CF  +0,940
[0,002 0,004 0,001 - 0,002 0,002 0,000 CL   0,006 CF   0,012]
Player X owns 2-cube:
  0,759 0,170 0,003 - 0,241 0,031 0,001 CL  +1,357 CF  +1,169
[0,003 0,006 0,001 - 0,003 0,002 0,000 CL   0,017 CF   0,018]
Full cubeful rollout with var.redn.
251 games, Mersenne Twister dice gen. with seed 825264581 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 0,12
Skip pruning for 1-ply moves.
Cube: 2-ply cubeful prune [world class]

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