Just discovered this BG forum on 2+2 which looks pretty good.

Playing on-line BG cash games there is usually a limit, for example playing $1-$4 (limit $4).
It is obvious than for games like $1-$2 the double point is at 50%. Also for $1-$4 when the cube is at 2, the double point is at 50% contrary to normal cash games with no cash limit where the double window is around 60%-70% depending on volatility etc. The same for takes in above examples where the take is at 25%. Actually depending on the rake % the above % should be slightly more.

My question is the effect of table limits (as opposed to normal cash games) in the $1-$4 Initial double position. My initial instict is that I should double more and earlier compared to normal unlimited cash games. The reason been that ownership of the cube by the opponent is less valuable than normal because if the game turns and he gets the advantage there is no value in his gammons (he will redouble at table limit of $4 and gammons will have no effect).
Is my above thinking correct? If yes how much earlier should I double? Most books provide reference positions of when to double based on unlimited cash games. I need to get reference positions for this.

Regarding $1-$8 games, I would assume that the table limit poses very little effect (compared to normal cash games) of when to double and reference positions of normal cash games are satisfatory.

In a 4 point limit game, you can also save slightly more gammons because you can let your back checker stay until the last roll to possibly get a late shot with no fear for a backgammon, since losing 6 points is equivalent to losing 4.

Thought about that too, i play some lowstakes games on Party Gammon lately and have switched to $1/8 or $0.5/4 just because it seems more "realistic", so to say.

Obvious but wrong.

For money your doubling window opens at 50% and closes at 80%, theoretically.

As far as I know no one has ever done anything in-depth with table stakes games.

Suppose you are bearing in against a back game and are about a 45% game dog but win a gammon every time you win, and let's say you have a checker off already so you are off the G. Not sure if I can create such a position so I won't try.

For money this would be a strong cube. You would win .45(4) - .55 = 1.25 points per game. With recube vig it'd probably be a close take or drop decision.

Suppose you are playing $1 per point with a limit of $8. You double, he beavers to 4 and recubes to 8. Now you are a 45-55 dog, so your double was a huge blunder.

Should say .45(4) - .55(2) = .7 points per game, cubeless. This'd make it a reasonable cube but easy take.

Thanks for the feedback Atrifix.

Why is it wrong that the Double point in games like $1-$2 is 50%.
(assuming zero commision, and assuming perfect play by opponent).
My understanding is that such a game is equivalent to a 2 away 2 away position in a match.
Or equivalent to a last roll normal cash game where you double at 50% (ie 19/36 rolls).

There is no value to your opponent in passing him the cube.There is no value in gammons at all under jacoby rule. As soon as my winning changes exceed 50%, I am the favourite, and doubling doubles my equity.

The same applies in most circumstances for $1-$4 games when the cube is at 2. Here there is some value because it might be too good to redouble. But it would be a rare and unusual position when that happens.

You can double some positions, if they are volatile, with chances significantly lower than 50%, down almost to your drop point of 25%.

http://www.bgonline.org/forums/webbb...mes;read=29347

This I do not understand. Why should volatility have anything to do with it when the table limit is twice the initial stake?
I understand the point of volatility when there is no limit.
Why would it ever be beneficial to double in the $1-$2 game at lower than 50%? (except if I think the opponent will drop).
If say now I have 45% changes, my equity is -0.10. If I double my equity becomes -0.20.

If both oponents understand the above then, the first player just doubles and the other accepts (you always play $2 games ). But of course not all undrestand. Someone might wait until he gets to 80%, so I drop and save some equity.

By the way, the link you posted does not work.

The theory is that you should double as soon as you have a market loss, assuming you would not drop your opponent's cube on his turn. More market losses (i.e., more volatility) makes it a bigger error not to cube.

Say you have two checkers on your 6 & 5 point and your opponent has two checkers on his 5 & 1 point [first position in the above link]. If you do not bear off on this roll you will have to take your opponent's cube since he is only a 23-13 favorite. Therefore by not cubing you ensure all your losses are 2 points while many of your wins are only 1 point. By cubing you kill your opponent's cube. So all of your losses remain 2 points but all of your wins are also 2 points.

As to whether that can possibly hold up in practice or not is better judged based on your opponent's play. I gave my thoughts on this http://www.bgonline.org/forums/webbb....pl?read=29383 here.

But when I talk about "doubling windows" I am speaking of theory, not practice. In practice I don't give much consideration to a window. Though figuring takepoints is still useful at certain match scores.

It is more or less the same conceptually; only slightly different in that your cash point is 75% instead of 68% so you don't lose your market as quickly as you would in a 2-point match.

Odd, works for me.

You are right.

Could not get the link to work, so I did some calculations to see how it works on your example of 6,5 v 5,1.
My results at this position were:
Probab of Win 42.22%, Lose 57.78%, Equity -0.1556
Doubling now equity becomes -0.3113.

If I do not Double now then and opponent doubles then
Prob Win +1 16.67%
Prob Lose -1 13.89% (drop if win changes after play is less than 25%)
Prob Win +2 23.18%
Prob Lose -2 46.26%
Equity -0.4338.

Strange result for my understanding of the game. ie Doubling at a disadvantage because the disadvantage increases when opponent doubles. Always thought that the main difference of analysing BG as oppossed to a static game like say Blackjack, was the value of the ownership of the cube because of the redoubling ability to the person who owns the cube. And if there is no redoubling capability then the game could be analysed like a static game (for doubling purposes). As you say this is not the case.

If I understand correctly the reason of this strange result in this example is because the game can end immediately (if I get 6,5 6,6 etc) with a prob 16.67% and if I do not double now I only win 1.

For practical purposes (ignoring end positions like this where the game can finish on this roll), especially in the beginning of a game, Would it always (or almost always) to have the Double Point at 50%?

Right..the point is by doubling you kill your opponent's cube, which you don't by not doubling. So ND gives your opponent full benefit of the cube on his shake but you don't get the added benefit on your (prior) shake.

This often comes up at certain match scores when you are trailing. E.g. let's say you are -5 -3 (5-away 3-away) and holding a 2-cube, playing a back game and you get a late shot with a strong board. You may be only 30% or something to hit. But hitting will lose your market. If your opponent wins he usually gammons you for the match anyway. Therefore it is often right to redouble at such a score, because you kill your opponent's gammons when you lose (he would have won 4 points anyway), but you ensure your wins when you hit are 4 points instead of 2 points.

EDIT: I should also point out that it is never an error to not double if you don't have a market loss.

Yes, generally speaking. I would usually wait until I have an advantage to double, sometimes a bit longer if I don't think there are any market losses.

However if you are playing a 2-point match or a $1-2 game rather than a money game I believe most games should be cubed by the favorite very early on, probably within the first two or three rolls.

Thanks for your Input Atrifix.

Regarding a $1-$4 game do you have any insight of how doubling should be approached (as opposed to normal cash game).
My instict says that I should be more aggresive (ie earlier) to Double than Normal cash games.

I honestly don't know.

• When your opponent recubes you have exactly a 25% takepoint, so on opponent's recube you have exactly the same decision as you would if he recubed to 4 at 3-away 3-away.
• Your gammon value on a 2 cube is still 0.5 (you can win +2, lose -2, or win +4, so risk is 4 & gain is 2), but both player's gammon value on a 4 cube is 0. Is it ever a good idea to recube in this situation to kill gammons? Let's say A wins 60% games with 30% gammons. B loses .3*4 + .3*2 = 1.8 points per game. By recubing to 4 he loses only .4*4 = 1.6 points per game. So this is something to keep in mind in very volatile positions.
• Your takepoint is a bit lower than the money value of ~22%. This is because when you recube your opponent will have a dead cube.
• Beavers are more or less worthless. If you are going to get the cube on 4 you can do it by recubing if things go well or holding the cube if they don't. The only reason to beaver is if the position is volatile enough that you will lose your market on your opponent's shake before you even get to roll (say, if opponent doubles you when he has a double shot & misses, or doubles you as a dog in a bearoff). You should not beaver cubes unless you are over 50% in the game as cube ownership is worth nothing.

With this in mind I believe you should be marginally slower to cube than you would for money and take marginally deeper. But for the most part initial cube play is about the same as it would be for money, just that the recubes are a bit stronger. Kind of the opposite affect of playing a 4-away 4-away match where going out with 4 points is extremely important and 2 points doesn't matter so much.

Just occurred to me that Snowie has a table stakes feature. If you have Snowie you can play around with it, though I haven't used it enough to see if it's any good or not. I know GNU does not have such a feature and I believe XG does not.

Thanks for the Info Atrifix.


Regarding the take Point in $1-$4, I found this article that ahs a table regarding take points on table limit games(sorry, do not know how the make the link active)
http://www.bkgm.com/faq/Variants.htm...ed_money_play_

Basically as you say there is very little difference on take points.
Probably there is a little difference on Double points as well.

Regarding Snowie, I do not have it. I might buy it in the future. I usually practise on Jellyfish and GNU.

Most of my play is on Fibs. I estimate my FIBS rating around 1830 (last 6 months my rating has been between 1800-1880). I recently started to play cash games on money sites. Because of very little experience with cash games, I am better in match play and I am trying to get some experience in cash games.
I have alredy figured out that it is impossible to make any serious money on Internet cash games because of the rake and because bad players are only willing to play for very small stakes.
I think I can make around 0.20 ppg (points per game) before the rake at levels of play of $10-$40 and a lot more on very low limits like $1-$4. Above the $10-$40 limits most willing players are too good.