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OLM 20141219B The Prime Factors
Posted By: kruidenbuiltje
Date: Saturday, 20 December 2014, at 9:45 a.m.
In Response To: OLM 20141219B The Prime Factors (Jason Lee)
24/18 8/6 is the gammonsave move.
After this move white has 43 pips to go and blue 38 to save the gammon.
The white position has a waste of about 13 pips.
I estimate the blue waste (for crossing over) is about 6 pips.
So effectively after this move the race is 56 vs. 44.
With blue to move that is 44 vs. 48, a 9% lead.
That is a redouble point, this is about 72% chance of saving the gammon.

Playing 8/2 wastes 4 pips, sorry 3 pips, that is about 6% gammons.
A hitchance will occur after {64,54,D3} = 5/36 x 11/36 (hits) = 4%.
And we need 12% wins to compensate for the gammons at equal matchscore.

What about wasting one pip (with 11/5 8/6) to prevent white from hitting with a 123 combination.
Such a combination occurs 9/36 times + D4 = 10/36.
The cost of such a hit is 9/36 x 25/36 (fanchance) x 8 pips = 1800/1296 pips = about 1,5 pip and more after further fanning.
So wasting one pip is worthwhile.

Further waste in the form of playing 11/5 6/4 does not seem worthwhile, since our hitchance (if any) will probably occur on the next move.

Answer: 11/5 8/6

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