Match 1, Game 3, Move 3, Forum double

[socksey]

Sorry, was that rather stupid of me?   

socksey



"The power of accurate observation is commonly called cynicism by those who have not got it." - George Bernard Shaw

[Zorba]

GNUBG 2-ply ROLLOUT:

Spoiler

Oh boy! Is it really this bad? I have a little doubt about the size of the error the rollout result gives (evaluations have it much closer), but there is no doubt that it's a big whopper with extras to cube this. The matchscore plays a big role in this. Only needing three points and ahead in the match, we should've been much more careful doubling in a (mutually) gammonish position.

Size of the doubling error in bold and underlined.

Rollout details:
Centered 1-cube:
   63,49  30,25   5,45 -  36,51   8,02   0,74 CL  +0,4638 CF  +0,5537
[  0,25   0,43   0,40 -   0,25   0,15   0,15 CL   0,0080 CF   0,0183]
Player factotum owns 2-cube:
   63,25  33,14   9,37 -  36,75   8,05   1,08 CL  +0,9276 CF  +0,3037
[  0,29   0,54   0,57 -   0,29   0,17   0,20 CL   0,0168 CF   0,0238]
Full cubeful rollout with var.redn.
1296 games, Mersenne Twister dice gen. with seed 857820087 and quasi-random dice
Play:  2-ply cubeful prune [world class]
keep the first 0 0-ply moves and up to 6 more moves within equity 0,09
Skip pruning for 1-ply moves.
Cube: 2-ply cubeful prune [world class]

No double: +0.5537
Double, take: + 0.3037 (-0.2501)
Double, pass: +1.000 (+0.4463)

No double, take (35.9%)

============================================================
Cube analysis
3-ply cubeless equity  +0,6204 (Money:  +0,5497)
   66,13  28,35   1,96 -  33,87   7,39   0,20
Cubeful equities:
1. No double            +0,6434
2. Double, pass         +1,0000  ( +0,3566)
3. Double, take         +0,5685  ( -0,0748)
Proper cube action: No double, take (17,3%)

Cube analysis
4-ply cubeless equity  +0,5542 (Money:  +0,4847)
   63,71  27,53   1,88 -  36,29   8,08   0,28
Cubeful equities:
1. No double            +0,5581
2. Double, pass         +1,0000  ( +0,4419)
3. Double, take         +0,3991  ( -0,1590)
Proper cube action: No double, take (26,5%)

[close]

[blitzxz]

Obviously, this rule won't help a player who's grossly misevaluating a position much. But that's not the goal of this rule. Also, the examples you give are not in any way contradicted by the Woolsey Rule, they are just situations outside the scope of it.

I think you fail to see the power of Woolsey's doubling rule: When there's any doubt in your mind about whether opponent has a take, you should always double. I consider it the single most best advice on using the cube, and even good players sometimes forget to apply it.

As said, the rule doesn't mean that there aren't other situations with a clear take or clear pass, where you should NOT double. And these are usually harder decisions to make. You will have to use other "tools" for those situations.

The reasons why Kit's rule works so well in practice are partly mathematical, and partly "psychological". Suppose you have indeed some doubt about whether it's a take. What are the scenarios?

If the double/take equity of a position is indeed close to 1, it's nearly always correct to double (certain lopsided matchscores are an exception). Also, it's often a pretty big to very big error NOT to double in these cases. Occasionally, even with the double/take equity close to 1, volatility may be so low that it's not a double yet. However, you will lose very little when you double those. And you may actually gain if opponent errs on the take! So, the rule works well here, preventing you from big errors at an extremely small cost.

If the double/take equity is more like 0.8 and thus a big take, it's often still correct to double these, sometimes by a fair amount, and if it's not, then you still won't lose much usually. BUT!!! Your opponent may well see the position like you did! And as such, have doubts about the take. If he drops, you gain a lot, whether it was a correct double or not. So the Woolsey Rule overall still works very well here.

If the double/take equity is more like 1.2 and thus a big drop, once more it's often still correct to double, and sometimes by a fair amount. It could be too good to double, but usually not by much, so you won't lose much on these. And once again, your opponent may have same problems evaluating as you did, and take your cube. Bingo! Once more, applying the Woolsey Rule stands to gain a lot at very little risk.

Of course, it's possible to misevaluate a position by more than this. Maybe it's a 0.5 take when you think it's close, or a 1.5 drop. Obviously, in those cases, you may lose quite a bit on a misguided double. But once more, it's not totally surprising to see your opponent misevaluate it as well, and the benefits from that only increase! Anyhow, even if you lose on those, you'd probably make errors from gross misevaluations anyway, so the Woolsey Rule is unlikely to make things any worse for you.

So overall, the Woolsey Rule is not a rule to help you evaluate winning chances or equity; it's a general rule on situations where you should double. It reminds you of the small risks in doubling compared to the big gains from either correct cube action by both, or an error from your opponent. It also reminds you of the fact that the question whether to double or not, should start with looking at opponent's take decision.

I'm so stubborn person that you can't change my mind so easily. And also I'm raised by bots. I only read about the law when I had already played over year analyzing every game with gnu. Of cource you want to be as close as possible to take point but to know when you're there you have to understand volatility which is the single most important thing when doubling. When vola is high you have to double far from take point because there is still big chance to lose markets and vica versa. And also you want to make hard decisions to opponent but there is no reason to believe that your opponent thinks same as you. To me Woolsey's law is all about this psychology. It tells you nothing about equities, volatility or nothing what's important to me when doubling. Only thing that it tells is that it makes opponents decision hard if he thinks same as me. And if you trust it as general guideline you end up doubling way too early in confusing positions which you don't understand or you easily wait too long for Woolsey positions when you actually should double right away because big volatility. But I'm not trying to sunk the whoie law because the general idea is pretty solid but it just doesn't suite my taste.