| |
BGonline.org Forums
Help with contact situations - Kieth Count (or other racing formulas)
Posted By: Daniel Murphy In Response To: Help with contact situations - Kieth Count (or other racing formulas) (Max Levenstein)
Date: Tuesday, 26 July 2011, at 11:33 a.m.
In the first position both players have stripped midpoints and you have four other outfield spares. The raw 98-108 pipcount suggests CWP of about 76% if you look here), or 75.7% by Kleinman count, and your analysis says 75.3%. But I think that difference may be all due to Blue's greater wastage because of the checkers on the 1 and 2 points, and indeed according to a Gnubg's one-sided database rollout Blue has about 0.76 pips more wastage than White.
I'll suggest that the chance of you losing by not being able to clear the midpoint is about the same as the chance of rolling 6-1 5-1 4-1 3-1 or 1-1 four times in a row followed by a 6-1 followed by a hit, which is very close to zero.
So for positions like this one where you have several spares and a midpoint to clear against an opposing midpoint, I'd ignore this tiny chance and treat the position as if there were no contact.
In the second position Blue has slightly less net wastage (0.66 pips says Gnubg). Over the board I'd still treat this as a noncontact position. Your analysis has CWP 0.40% lower than in the first position, and I can believe that is because of the increased contact. If I suggest that the chance of contact losing the game for you is about the same as rolling 6-1 5-1 4-1 3-1 2-2 6-2 5-2 4-2 or 3-2 four times followed by 6-1 followed by a hit, that's about 0.3%.
Your third position suggests that with a few spares, opposing outfield points blocking threes costs about 2.5% CWP -- I guess I can believe that -- another 4% if fours are blocked, and another 2% if fives are blocked. That all seems reasonable and worth remembering, but you might check the EPCs on those, and also consider that part of the reason your CPW is going down is not because of the chance of not clearing but because your 4-4 or 5-5 are no longer excellent racing numbers.
Your sixth position with three spares has higher CPW than your fourth position with four spares, so Blue must be gaining a bit from distribution -- Gnubg says Blue's wastage is now about 0.3 pips less than White's.
In the seventh, it's interesting that having two spares instead of three doesn't cost you much, but again you might play around with this a bit more and see how much of that is due to better EPC. And in the last position, Blue's wastage advantage is about 0.6 pips. So if in the last two Blue and White's positions were more balanced, these borderline cube decisions should become clearer no-doubles.
I can't recall reading a detailed study of a series of similar positions -- you've certainly uncovered some useful information in your excellent start on one!
| |
BGonline.org Forums is maintained by Stick with WebBBS 5.12.