[CENTER]White - Pips 141. Match Score 4/7

Black - Pips 150. Match Score 1/7
White on roll. Cube action?

Take or pass, is the double tg and why?

Hi

after an opening 52 split - 55 - dance we get a clear dp according to K.Woolseys Encyclopedia. The position here seems better for white to me than this + matchscore. Imho: tgtd

Stick's rule should apply here. Leader never doubles with contact at 3 away 6 away or better (3 away 7 away, 3 away 8 away, etc)

The window where double / take is correct is very small. Usually it's No double or Too Good. Stick advises don't even try to find this window. Instead "never double."

As always in backgammon it is about risk and reward. When the leader doubles, he lessens his own gammon value while giving the trailer powerful ownership of the cube.

Holding the cube, the trailer only retains his winning chances at Crawford away if he loses. Yet he can gain quite a bit by redoubling to four. He completely kills the leaders gammons with a cube on four, while giving himself the chance to possibly win four points, or even eight on a freak gammon. Because of these factors, the trailer will redouble very very early.

Also because of these factors, it is the leaders strategy to keep the cube on one and just try to win an undoubled gammon. This would take the leader to Crawford, which is a pretty good accomplishment but without the risk of a turnaround and a four point loss or that freak gammon and an eight point loss. Bottom line, leader doesn't want to see a four cube.

So in this position, 3 away is Too Good. He should hold the cube and play for the gammon.

First of all, tyvm for your answer.
This position was sent to me by a good friend who was playing against xg, got doubled and passed it. He wondered if there could be a mathematically approach for him to prove that this is a take. Me, I am just more or less confident to do these calculations in moneygames, but in match play, calculations like these involve for my small brain too many factors to include in the calculation.Maybe someone like Mr. Robertie could? IMO no human being would double this position and everybody just would go for the gammon.
XG ++ says that it's a double/take and a blunder not to double, so maybe somebody could prove it mathematically?

XGID=-a--BaEAB---dCa--a-c--b-bB:0:0:-1:00:1:4:0:7:10

X:XG Roller++ O:Player
Score is X:4 O:1 7 pt.(s) match.
+13-14-15-16-17-18------19-20-21-22-23-24-+
| X O O | | O X O X |
| X O | | O O |
| X | | O |
| X | | O |
| | | O |
| |BAR| |
| | O | |
| | O | |
| O | | X |
| O | | X X X |
| O X X | | X X X |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 141 O: 150 X-O: 4-1/7
Cube: 1
X on roll, cube action

Analyzed in XG Roller++
Player Winning Chances: 71,71% (G:45,19% B:1,85%)
Opponent Winning Chances: 28,29% (G:7,05% B:0,44%)

Cubeless Equities: No Double=+0,911, Double=+1,480

Cubeful Equities:
No double: +0,890 (-0,082)
Double/Take: +0,973
Double/Pass: +1,000 (+0,027)

Best Cube action: Double / Take

eXtreme Gammon Version: 2.10, MET: Kazaross XG2

Using CODE tags (click the #):

Do you ever post rollout results on this forum? I am asking because generally I don't particularly trust evaluations in these very gammonish positions at lopsided scores. 1-2 percent in game winning chances can result in a large swing.