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BGonline.org Forums
41S-11 question
Posted By: Nack Ballard In Response To: 41S-11 question (David Rockwell)
Date: Saturday, 30 January 2010, at 9:36 p.m.
I did a rollout to try to understand the value lost in 41S-11F (Float 24-23, 6-5(3)) due to the floating checker versus the value lost by not splitting all of the way to the 22 point with e (each 24-22, 6-5(2)), the best play. I did this by playing only three aces instead of the required four. I don't know how to Nactate this illegal play, if indeed there is a way. I will use ? for this one time usage. I have:
41S-11 [e ?16 F33 E61] - 5k
I was quite surprised to see that the float was as costly as the failure to split all the way. I expected the float to be relatively insigificant. Of course, if I was sure about that, I wouldn't have done the rollout. I am wondering if I need to extend these rollouts or not. Does anyone have any knowledge of this position and whether or not the rollouts look reasonable?
First, I agree with Paul's articulate explanation for the 6/5 float being a harmful ace. To further elucidate (perhaps beating a dead horse, even), if you end up with two 6pt spares you can play 6/5, whereas if you end with two 5pt spares you can't play 5/6. This is why, intuitively, experts see the two-5pt spare position as ugly but the two-6pt spare position as tolerable. (Even if other inside points are subequently made, a distinction remains; for example, if the 4pt is made, it relieves the 5pt-5pt situation because an ace can improve the distribution, but it also relieves the 6pt-6pt situation because a deuce as well as an ace brings relief.) You haven't actually stacked yet, but stacking will be a more palatable option if your spare is on the 6pt, and therefore the equity filters back.
I would add to that another important reason, and it's much easier to explain: There may come a time when you (moderately to badly) need a spare ace to play. If you play 6/5 you've already burnt that ace.
In case you grasp (or already grasped) those reasons but still wonder if the 6/5 ace really costs as much as .033 - .016 =.017 or if some of that is due to variance, I offer below some additional data (two or three bots results averaged for each position) where the relevant comparison of a fourth ace involves a back-checker scoot versus 6/5:
21S-11 [e F20]
21S-11e-11 [E e24 m30 F33]
41S-63R-11 [E N14 e28 F38]
41S-65R-11 [N E8 e32 F28]I have numerous other third roll positions with a 6/5 float candidate rolled out, many of which make floating a smaller error, but in each of those cases it is because the fourth ace is harmful either way (i.e., it's pick your poison). Instead, I selected three positions that should give you the best idea. Note, though, that E's 22/21 is a helpful fourth ace, while e's 24/23 (walking into Opp's three-checker 8pt) is a harmful fourth ace (in one of the positions more harmful than 6/5).
In case it isn't clear, the other three aces are 23/22 6/5(2). Ignore the N play for your purposes: It is the E/e/F comparison that is relevant.
I realize that doesn't tell you everything you need to know because in none of the positions have I rolled out the illegal three-ace play, but the .017 difference in your 41S-11 rollout is not at all surprising to me (I would have guessed .014). You should extend it, though, if knowing the exact difference is important to you.
Regarding the Nactation of illegal plays, I have not given it much thought. If I wanted to use a single character, I would just wade down the lower-case/italic/underline hierarchy until all legal plays are exhausted (sometimes just one or two), but in many cases it would still require use of illegal-specific conventions I haven't yet created, and I probably won't bother. Illegal plays arise so rarely that I recommend falling back on trad notation in those instances (as well as marking it "illegal").
That said, I think your use of "?" is ideal here, because it's not a character otherwise used in Nactation, you explained what it meant, and it didn't take up additional space in the nacbrac (where you want the information condensed).
As a side note, I have done several rollouts of the (legal) position using MWC settings. The absolulte equity of these vary by a surprising amount from the Supremo rollouts. The differences between plays are somewhat consistent between the two settings.
Like you, I am often surprised by the size of the difference in absolute equities produced by different bots and different settings, though they fortunately still seem to produce relatively consistent margins, and it is the latter to which I mostly pay attention.
I sometimes see people (not you) show rollouts or display data tables in which some plays are rolled out at different settings, some are evaluated, etc. It's a veritable horror show. We should always compare apples to apples.
Nack
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