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Should Black Run?
12-26-2014
, 01:56 AM
Here's another situation I run into from time to time which stresses me a bit. Should black run or stay put?
12-26-2014
, 06:18 PM
White - Pips 142
Black - Pips 155
Black to Play 6-2
XGID=-aa-B-D-B--BcC---bbbb-AbA-:0:0:1:62:0:0:0:0:10
This is the same position, but with a different roll. Unlike the OP, you cannot safely play the 6 down from the midpoint. You can, however, make an anchor with the 2, and use the 6 to hit on the 2pt. Is running better? Between the two running plays, 24/16 or 22/14, which one is better?
Mike
Black - Pips 155
Black to Play 6-2
XGID=-aa-B-D-B--BcC---bbbb-AbA-:0:0:1:62:0:0:0:0:10
This is the same position, but with a different roll. Unlike the OP, you cannot safely play the 6 down from the midpoint. You can, however, make an anchor with the 2, and use the 6 to hit on the 2pt. Is running better? Between the two running plays, 24/16 or 22/14, which one is better?
Mike
12-27-2014
, 06:31 AM
The problem with making the anchor and hitting is, that you are almost virtually behind a 5-prime. If white hits back, you now have three checkers behind that blockade. If he doesn't hit back, you will get a real timing problem, because the pipcount difference will be even or worse. Probably the importance of a good timing (and some other factors) is shown, when black is a substantial amount of pips behind.
White - Pips 142. Match Score 0/64
Black - Pips 166. Match Score 0/64
Black to Play 6-2
Created with www.BGdiagram.com
Black - Pips 166. Match Score 0/64
Black to Play 6-2
Created with www.BGdiagram.com
Code:
1. 24/22 13/7 Eq.: -0,472
0,397 0,085 0,003 - 0,603 0,181 0,006 CL -0,304 CF -0,472
2. 22/14 Eq.: -0,636 ( -0,164)
0,381 0,084 0,004 - 0,619 0,284 0,010 CL -0,444 CF -0,636
Truncated cubeful rollout (depth 10) with var.redn.
146 games, Mersenne Twister dice gen. with seed 766752762 and quasi-random dice
Stop when std.errs. are small enough: ratio 0,1 (min. 144 games)
Play: world class 2-ply cubeful prune [world class]
keep the first 0 0-ply moves and up to 8 more moves within equity 0,16
Skip pruning for 1-ply moves.
Cube: 2-ply cubeful prune [world class]
12-27-2014
, 09:53 AM
White - Pips 142
Black - Pips 155
Black to Play 6-2
XGID=-aa-B-D-B--BcC---bbbb-AbA-:0:0:1:62:0:0:0:0:10
My 5k rollout of this position shows that 24/16 beats 22/14 by about 19 millipoints. That's 0.019. Hitting on the 2pt is a distant 4th-best, trailing the top play by 60 millipoints. Getting the rear checker to daylight is clearly correct.
Mike
Black - Pips 155
Black to Play 6-2
XGID=-aa-B-D-B--BcC---bbbb-AbA-:0:0:1:62:0:0:0:0:10
My 5k rollout of this position shows that 24/16 beats 22/14 by about 19 millipoints. That's 0.019. Hitting on the 2pt is a distant 4th-best, trailing the top play by 60 millipoints. Getting the rear checker to daylight is clearly correct.
Mike
12-27-2014
, 04:31 PM
The situation changes when the blot is on the 21 point. In that case 24/21 8/2* is best.
White - Pips 142. Match Score 0/64
Black - Pips 154. Match Score 0/64
Black to Play 6-3
Created with www.BGdiagram.com
Black - Pips 154. Match Score 0/64
Black to Play 6-3
Created with www.BGdiagram.com
Code:
1.24/21 8/2* Eq.: -0,357
0,446 0,129 0,004 - 0,554 0,157 0,005 CL -0,138 CF -0,357
2.24/21 13/7 Eq.: -0,374 ( -0,017)
0,443 0,112 0,004 - 0,557 0,148 0,005 CL -0,152 CF -0,374
3.24/15 Eq.: -0,413 ( -0,055)
0,459 0,113 0,006 - 0,541 0,250 0,008 CL -0,221 CF -0,413
Truncated cubeful rollout (depth 10) with var.redn.
147 games, Mersenne Twister dice gen. with seed 766752762 and quasi-random dice
Stop when std.errs. are small enough: ratio 0,1 (min. 144 games)
Play: world class 2-ply cubeful prune [world class]
keep the first 0 0-ply moves and up to 8 more moves within equity 0,16
Skip pruning for 1-ply moves.
Cube: 2-ply cubeful prune [world class]
12-27-2014
, 07:35 PM