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BGonline.org Forums
Lopsided Score
Posted By: Stick In Response To: Lopsided Score (Steve Mellen)
Date: Wednesday, 12 May 2010, at 5:21 a.m.
This is a double of monstrous proportions. You don't have to be a genius to figure out as the taker your opponent's gammon value on a 4 cube is highly elevated, that if you take the cube is more or less dead as your recube vig is as close to non-existent as it can be while still existing, your own gammon value probably shoots as low as your opponent's does high. Everything so far has been in favor of aggressive doubling and a cube is mandatory. Can we take?
Oh match equities in 29pt matches, not exactly my forte and I wonder where oh where were you playing a 29pt match?!
Let's try this:
- DP gives -6 -18 or 92%
- DTL gives -6 -16 or 88%
- DTW gives -2 -20 or 99%
For the sake of trying to figure this out OtB I will ignore any recube vig that might exist and also take the gammon value down to 0 for the leader. I will keep these items in the back of my mind if the decision is close then they will definitely swing it to a take.
I also only know the MET out to 15pts so I've made some common sense adjustments to get the figures above. They should be close enough. Our raw take point is then 4/11 or ~36%. The biggest hole I feel so far in my calculations is about to come, the gammon value. I would wing it at .9 on feel alone making my take point 36% + 9/10ths of my gammon losses. Of note here is that if I am making an educated guess at my gammon value I should undershoot it since I didn't figure in my own gammon value which while not worth much at all would counterbalance any small error in that direction.
How many gammons does my opponent win from here? He has 15 numbers that hit the blot on the 5pt, 22, and 33 which are quite good pointing on the 21pt blot, and 11 which hits also. All the entering sixes will hit loose on the 21pt (6 rolls + already mentioned 65 is a double hitter), all entering 4s will hit loose also as well as the remaining 31. This should add up to every entering roll hitting something! That means only 4 rolls, the dancing numbers, don't put something in the air. Now it's only a 3pt board and as the taker you are currently ahead in the race. With the particularly high take point and augmented gammon value though we have to be careful. I'll estimate 20% gammon losses for the taker here meaning he'll need 36% + 18% or 54% net wins to take.
Wow that's high but it seems like a fair number. Is Blue a favorite in this position? I don't think so, so RD/P. I also failed to figure in the backgammon value which on a 4 cube for the trailer is significant to say the least. He may only win at most 1% bgs from here but something to figure into the equation if it was a close decision. Since I've already concluded it's a pass, I don't need to figure out if it's more of a pass and can leave the bg figure alone.
Let's now cheat and go back and look at some of my numbers but with the help of GNU and the mec26 MET.
I figured -6 -18 as 92%, it is actually 91.5%.
I figured -6 -16 as 88%, it is actually 88.2%.
I figured -2 -20 as 99%, it is actually 99.3%
You see how close these numbers appear? The point to this story isn't that extrapolation works, it's the huge difference in take points we get by approximating at these lopsided scores. Using my figures for the raw take point which look pretty damn accurate in comparison we arrived at a take point of about 36%. Using the exact numbers from mec26 we get:
- DP gives -6 -18 or 91.5%
- DTL gives -6 -16 or 88.2%
- DTW gives -2 -20 or 99.3%
This gives us 3.3/11.1 as the raw take point instead of 4/11 (36.3%) dropping the take point down to 29.7%! Quite the difference for what amounts to more or less some rounding. So we have our actual raw take point of 29.7% and looking up the gammon value it is listed as .92 (rounded) so again, close. If we use that gammon value with our new raw take point and our estimated 20% gammon losses we now only need 29.7% + 18% or 47.7% to take. Hmmm, this is could be close, now we have to figure in backgammon losses which with only two blots floating around and a three point board can't be much, 1% tops. The bg value rings in at 2.4% so adding that on to our 47.7% figure we still need to be a favorite in the game and I don't believe we are so pass.
This post advocates clocked play if you didn't catch that. People say clocked play favors the stronger player but I doth protest. The weaker player has far less to think about than the stronger player. You give the Tardieu's and the O'Hagan's of the world all the time they could ever want and they will pipple the hell out of you. I would certainly take some time on this problem OtB as it's a recube in a semi-gammonish position at a lopsided score but I wouldn't take anywhere near the amount of time I would without a clock.
Stick
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