Hrqls: wellllll...i knew you were nervous about experimenting! I really didn't want to double, that game was fun! But..i like points too..

OK， new question. In this game:

1) would you play the double hit on the 6-4 roll?
i didn't, because without the cube, i didn't feel that taking the risk of "squandering" a 10 roll for no chance of the increased reward of a gammon was worth it...leading to the second question...

2. could this be one of the situations where you'd play differently based on a cube or not? If it's not, what's the most striking opening example you can think of?

Also, playbunny, i don't understand the terminology of "gaining blocks", hoping for something didactic here!

http://brainking.com/cn/ShowGame?g=1406288

playBunny: Direction button. Got it. Works now. THANK YOU. (And Thank God too- because I'm not sure I would have been able to go on with this otherwise great book!)

redsales: "i knew you were nervous about experimenting!"

It can sometimes be said that asking questions about a game in progress gives an advantage to the one asking. Not this time!

Quick definitions: didactic - adjective: instructive (especially excessively)
Wot me?

"gaining blocks" - poor choice of words given that there's the standard "making points".

1) I'd do the double-tap. If hit there's every chance of making a nice anchor with the blots on 5 and 4 so it wouldn't be a total disaster. GnuBg says .. double-tap for best move. It says to hit one of the blots with the next 3 choices and making the 2-point is only 5th and a blunder! (-.100) The hitting priority doesn't surprise me because tapping a naughty blot sharply on the nose is the thing to do at the beginning but I'm surprised that making the point is considered blunderful. I guess another part of that is because the blocking effect has been lost given that the point is behind the escaping backrunners. A kind of bolting the stable door thing.

2) Striking opening examples where non-cube (or rather non-gammon) is different from cube. Hmmm. I can't think of anything striking offhand. I tend to play gammonish anyway and have to remind myself not to.

redsales: *nod* thats why i thought it to be a very good move :) its often very nice to know your opponent in bg

btw in the messages i the game redsales worked even more towards this point by stating 'one is going down hard in this game' (or something like that :)) .. i had to agree (with a smile :)) and next turn i felt like i had to drop the double :)

i would take the double hit, leaving only 1 single, and your opponents board empty so you would have no problem getting back on the board

Pedro Martínez: Even without looking the games a score of 20 won games out of 20 games played, in a game of luck like Backgammon and ESPECIALLY in a game of much luck like Hypergammon, is something no one can achieve! Only if his opponents were random-movers. But i guess they were human species with a kind of intelligence.

Assume that someone is very skillful at Hypergammon. That would give him let's say a 58% advantage over his opponents to win a game since at Hypergammon even a huge skill difference is rejected by the huge luck factor in this game.
Then in order to win both 20 games the probability of that is 0,0019% or 1 to 54000.

Also if you see some of his games you can obviously see stupid play from his opponents.....

Alsi i wonder why he plays with an ix almost every time.....?

I a so depressed!
Can someone please put this position into on of your programs and tell me the odds of me losing this game? Also the odds of me getting a gammon? And winning without a gammon?

I hate this game!!!!!

http://brainking.com/en/ArchivedGame?g=1405138&i=50

Czuch:


Just after Sue's 3-3 you had a 91% chance.
When you then had to leave a blot it went down to 84.5%.
When she hit the blot it went down to 60.3%.
At the point just before Sue started bearing off it was back up to 70.9%.
After her first bearoff and a gap opened it was 71.6%.
After you got your man back in it was 74.3%.
When she hit you again it dropped to 66.4%.
By the time you'd finished dancing and got back in it was a mere 23.5%.

playBunny: Thank you! WebTV doesnt have much ability...
This type of game is a good example of how I plummeted from 13th to where I am today.... not doing much better in my poker games either! LOL!

Czuch: Sorry to hear that. $$$$$$ Where can I come and play you.

playBunny: HAHA LOL... you already refused all of my game invitations!

Czuch: Heh heh. Forget the Backgammon, I just want your money!

Czuch Chuckers: you know, internet access is quite cheap these days. If you really like using your TV as a "computer" monitor for internet surfing, on most modern TVs, you can run a coaxial cable from your hard drive to the TV to make it your monitor, that would be a natural transition for you WEBTV users. With that capability and WEBTV's costs, I really can't see it having any advantages anymore.

Czuch Chuckers: why did you resign in the last move ? you could have rolled a high double and still win

that game was a nice example of how a backgame can win :)

Hrqls: You cant resign without seeing your next roll.... it was double twos, I think! That game should have been a gammon for me and we should be tied at 4 each, but NOOOOOOOOOOOOO!!!!!

It is a good example tha a back game can win, but that will only happen once every 25 situations or so, although that number seems too high to me.

Is it against the rules here to have a program assess a situation to help determine the probability to get a gammon or if a double should be offered?

Czuch: "Is it against the rules here to have a program assess a situation to help determine the probability to get a gammon or if a double should be offered?"

For sure. You should only analyse a chequer play or cube decision, after you've made it. Same with discussing it here.

"It is a good example tha a back game can win, but that will only happen once every 25 situations or so, although that number seems too high to me."

That 1/25 is much too low. Have a look at those numbers again. Sue had a 1/10 chance even when you were down to your last 6 men. With a double-anchor back game your chances can be as high as 30% and is why you should be hesitant about doubling if you're winning and ready for the cube if you're the one playing the back game.

Czuch Chuckers: i meant at the end of the game

she just rolled a double 2 and could bear all her men off except 1

you had only 4 men in your home, so either a double 4,5 or double 6 would win you the game ... that still was a chance of 1/12 to win .. but you resigned and threw away that chance .... we will never know if your next roll would have been a high double though :)

Hrqls: No, that was my double 2 that I did n ot use....

is it always wise to bear off as many pieces as possible in the end game ?

for example in this game .. i roll double 2 and beared (bore?) off 3 pieces ... but this leaves me with 3 empty positions and a pile on 6 ... should i have beared off only 1 or 2 pieces and reduce the pile on 6 instead ?

Okay, I was offered a double here and accepted it..... what was the best play and why? (btw....his next roll of double 4s was not availqable for my decision) (nor his double 5s on the roll after that!)

http://brainking.com/en/ShowGame?g=1411482

Hrqls: am not an expert, but my opinion is that you have to take as many off now as possible, and hope for a double 6s next turn, as double 6s is as likeley as any other roll you may get.

Hrqls: If you miss bearing off a piece with the current roll, why would you be doing so? To save the risk of being forced to miss on bearing off at a later stage. But that's voluntarily falling behind because of something that's only a possibility.

There are times when you shouldn't bear off as much as you can. Unfortunately it's been rare enough for me that I can't think of any examples and I still have to ask GnuBg to see whether I chose correctly.

Czuch: The best play would have been to put a link in your message.

playBunny: *nod* thats what i tell myself all the as well and why i bear off as many as i can ... the only really bad thing that can happen is for me to roll a double of an empty spot and therefore missing 2 bear offs while i maybe could have prevented that if i had not beared off as many as possible ... but i have no example of such a bad thing (yet :))

i began to wonder some time ago when i beared off as many as possible on a roll on dailygammon, and the site didnt continue with a predicted next move .. so i assumed what i did wasnt the best move (according to the sites engine)

playBunny: okay, back to your job of doing what I should bedoing if I had a computer! LOL, Thanks!

Czuch: Lol. I was ahead of you. I took a guess that it was a current game so I've got the whole thing staring at me. Oh dear, oh dear. I don't think it's cheating to say don't redouble!

But the double that was offered .. you were right to snap it up - it was way to early. All your opponent had was an anchor giving 60% win including 15% gammons. Not enough by far. That 4-4 was handy but still not enough. Had the double come after the 4-4 it would still have been too early. And after hitting you and you dancing? Not as bad but not time to double. The 5-5 was good. Chances went up to 80% but you got in and hit back. Bad time to double then as well.

But then you got hit again and danced. But then it was beyond doubling! Time to get out the frying pan and chase the sizzle.

playBunny: Czuch: "Is it against the rules here to have a program assess a situation to help determine the probability to get a gammon or if a double should be offered?"

For sure. You should only analyse a chequer play or cube decision, after you've made it. Same with discussing it here. "

No! About the first case: You should NOT analyse a chequer play or cube decision, after you've made it.

Why? Because you may have an exact position later against another opponent or the same one! So you would gain inappropriate knowledge that comes from a computer! Cheating!
Also you should wait all games here to finish before analysing with a computer anything! Why? Because you may have a position you analysed so you will gain that knowledge and play according to computer's analysis.....
So in short: We should never use computer for analysing anything until we stop playing here.....

In the second case: "Same with discussing it here."
Again another person may meet the exact position with what you had and shown with your analysis so he would take advantage of it. So no more analysis here until all games finish. In 15-20 years i guess.....

Pythagoras: Thats a lot of work for such poor sarcasm ;)~

It does bring up a good point though.... when is it okay for advise?

I think you shouldn't analyze until after the game (not the match, just the current game). If you analyze immediately after a move it may give you insight into the position that you wouldn't otherwise have that could be used next turn.

I once read in a backgammon book (I think it was Robertie--I haven't read that many) that the break even point for taking a double should be 25%. If you win 25% of the doubles you accept, this person wrote, over the long run, you won't be behind any more points than if you dropped every game for single stakes (for instance, over the course of four such games, you'll be down 6-2 instead of 4-0, etc.).

This reasoning seems to me to miss one crucial factor--volatility. In a nutshell, I would rather be down 4-0 than 6-2 in, say, a 9 point match because 6-2 puts me closer to losing. Consequently, I think you need to adjust that 25% up--you need more than that to accept, and you need less than 75% to double. But I don't know how much to adjust that. I guess it would depend on the count in the match, length of the match, etc.

Thoughts on this?

so its best for me to wait until a game has finished before i bring a position here to discuss ? even though i already made my move ?

i will wait a bit longer with my next questions then :)

Hrqls: grenv said "If you analyze immediately after a move it may give you insight into the position that you wouldn't otherwise have".

That wouldn't apply to a cube decision unless recubing wa sin the air but woudl to chequer play.

With chequer play it depends on the move and the stage in the game. If it was about whether it was wise to risk putting a blot somewhere and that blot's been hit taking the game into a new phase then there is no danger of gaining inappropriate knowledge about the current position - too much has changed.

As an example of a case where I wouldn't give advice, say you are trailing badly and have hit a last-minute blot and are trying to contain it. I wouldn't discuss how you'd lay your backrunner net down or build your forward blockade on a particular move because the advice would be strategic and cover that whole phase. On the other hand I was happy to discuss Czuch's game just now because there was nothing he could gain from anything I said.

playBunny: I agree it depends on the position, and what knowledge you gain, however I would err on the side of caution if you aren't sure.

pentejr Yes, the %age changes slightly depending on the match score, but not as much as you might think. You also have to account for gammons either way so a simple percentage is not useful until both players have borne off.

What you need to do is work out the chance of winning for each match score (there are tables) and figure it out from there.

So in a 9 point match, ignoring gammons, if I refuse my chance of winning from 0-1 is about 44%.

If I take the double I will either be at 0-2 or 2-0. The chance of winning from 0-2 is about 37% and, conversely, from 2-0 is about 63%.

So if my chance of winning the first game are currently x, then my chances of winning the match if I take are .37(1-x)+.63x = .37+26x

So to equalize to teh 44% chance if I drop, then .44 = .37+.26x
.26x = .07
x = .07 / .26
x = about 27%

Which, as you said, is a little more than 25%

:)

grenv: however I would err on the side of caution if you aren't sure.

Yep

If the rules to Backgammon and Nackgammon are the same- I assume that the correct strategy for Nackgammon is slightly different from a godd Backgammon game- because of the two extra chequers? Are there any general principles for Nackgammon that differ from Backgammon. (I finally noticed I can set GNU to play Nackgammon.)

DragonKing: Yes the stratergies are very different. Though the dice will decide if you play an attacking game or defensive. Best way to find out is to play, you'll soon notice different ways to play.

playBunny & grenv: thanks.
just tell me if i ask a question too soon and i will postpone it until the game has been finished :)

the best way to learn is from examples i think, thats why i keep asking about positions which came up in games i played :)

Hrqls: No problem. I'm pretty sure I speak for grenv as well in saying that that's always been a consideration when we answer a question. :-)

playBunny: *phew* so i can stop sweating now ;)

Hrqls: No carry on sweating and make sure you bottle it. I know a guy who can get $$$ for refined blond sweat. ;-)

(Sue, you can delete this one once we've finished chuckling )

playBunny: lol! isnt there a difference in smell between male and female ? i should ask the mosquitoes, they always pick my gf first :)
(but she isnt blonde ... so maybe its not the sexe but the color ?)

i know .. i know ...

Hrqls: Aye, there's a big differences in pheromones (but I don't think it's that for the mozzies either as I'm the target amongst people that I know).

playBunny + Hrqls: I leave for one day and this board gets off track . . . who knew that a backgammon board would get into hypothetical geneto-biology. ;)

ColonelCrockett: Lolol. Where've you been when we needed your guidance? Off on your own blood sucking quest, no doubt!

[Not an insult, our Colonel is a vampire.]

ColonelCrockett: In other words.... you missed all the fun!

playBunny: oh, yes! ;) I've been a very aggressive little vampire! (I've brought the board to yet another subject, for shame, lol)

Eriisa: ooookkkk ;)

ColonelCrockett: OOK? Are you the librarian at Unseen University?


[Now we're waaaay off topic and into Discworld, lolol]