Re: [Bug-gnubg] Emailing: 2003-11-23-gnubg-user-5.sgf

[Joern Thyssen]

On Sun, Nov 23, 2003 at 08:16:12PM -0500, Daniel Robak wrote
> 
> I am sometimes questioning how the odds percentage is
> calculated. 
> I found myself in this attached position and I rolled a 5,1.
> A gammon is very likely, the only chance to escape a gammon
> would be to roll doubles on the following roll. Moving 17-11
> only allows one possible double to avoid a gammon, moving
> 17-12, 11-10 gives me three possible doubles to avoid a gammon.
> How can this result in only .002 difference in equity?

This is because gammons doesn't count much. Saving gammon is the
difference between -1,-4PC and -1,-3PC; the trailer needs to win two
games or a doubled gammon at either score. The only difference is the
free drop at -1,-4PC which is typically worth approx 0.4% MWC. The MWC
gain from 17-12 11-10 compared to 17-11 is thus 5/6 * 2/36 * 0.4% MWC =
0.02% MWC

At -1,-5 0.02% MWC is equivalent to 0.01-0.02 EMG.

Jørn

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