Pythagoras: Hey, that looks close to what I thought!!

playBunny: I thought I had heard that computer analysis had ressurected the 2-point opener.
Aye, I'd gained that impression as well and it's been my preferred move for some time now. There's always the possibility of operator error, lol.

64 with making 2-point is the best choice in a gammon-go situation. That means when you hunt a gammon....
But it's a bit inferior in my opinion in general games' situations.....See here for some 2-ply rollouts!

grenv: Aye.

I've added the gammon-go to the analysis post below. Making the point is judged best.

Hrqls: I was only comparing the other two openings since we were talking about gammon saves and gammon goes. Of course 24-18 13-9 is possibly best overall, particularly in light of playBunny's analysis.

playBunny: I would tend to make the 2-point in games where the gammons don't matter, I thought it was back in vogue as well.

Your numbers are not all that conclusive in the matter. It looks like they would favor making the 2 point when trying for a gammon though, any conclusion on that?

alanback: I'd love to do it and I'm sure it makes sense. But it also makes for a million cups of coffee. Well, maybe not but a 0-ply is instantaneous while 2-ply can take 3 seconds or so per dice roll and 3-ply takes about 7 seconds (both timings longer for a double and perhaps highly spread positions, etc). The rollout at 0-ply took about an hour and a half so I shudder to think what a 2-ply would require, let alone a 3-ply. There is the option of doing just the first N moves at a higher play and then reducing but I haven't tried that. I don't know that it would make that much difference on an opening move rollout. I'll have to try it ...

The writers of Gnu say that 0-ply is adequate as the errors would tend to balance out for the two players and the dice are random beyond the first two rolls anyway and blah, blah, but only the future will tell us how correct they are.

I thought I had heard that computer analysis had ressurected the 2-point opener.
Aye, I'd gained that impression as well and it's been my preferred move for some time now. There's always the possibility of operator error, lol.

Paul Magriel's updating his 70's classic to correct the "mistakes" of that era and also include more about the cube. He's doing it conjunction with some other guy (whose name I can't remember) and they're doing full rollouts on Snowie of all the openings (and maybe all replies?). Hopefully they'll be able to go well beyond 1296 which has far too high an error range for the rolls with subtle differences. I guess it'll be taken as the definitive data for the next wee while..

playBunny: I thought I had heard that computer analysis had ressurected the 2-point opener. I see you did your analysis on 0-ply, I would be interested in seeing a 3-ply result. Or does that not make sense in a rollout?

Hrqls: So in the double match point (DMP) situation the best moves are the drop-and-split and the run-for-home. The difference between them (0.008) is only just bigger than the possible error, so they make be closer than reported or even reversed.

In the gammon-save situation the run-for-home is more clearly judged to be the better move. In both cases GnuBg judges making the 2-point to be a fairly Doubtful move.

Hrqls: Lol. I forgot the column headings. I'll put them in...

Okay, the Move number and Move columns are obvious. The percentage columns are the expected Wins, Wins by gammon (included in the Wins) and Wins by backgammon (including in Wins and W.G) plus the corresponding Lose percentages.

The Equity, is how GnuBg evaluates the potential earning power of the move. 0.000 would mean that there is as much lost as won. 0.018 would indicate a small gain. The -0.202 in the gammon-save situation means that the roll and move is not good in match terms. Perhaps Alan or Pythagoras can explain that one as I'm still uncertain about what equity means in absolute terms.

The important value from the point of view of judging the relative merits of the moves is the last figure, in brackets. This is the difference in equity between that move and the best move. With the levels that I use anything worse than -0.010 is Doubtful and anything from -0.050 is a Bad move. (Thus move 5 in the gammon-save situation is an error because 24/20 24/18 leaves the player open to several double-taps, which is hardly a gammon saving kind of thing to do!)

playBunny: uhm ... care for a little explanation ? ;)

(i only played with gnubg for a couple of days and that was several months ago :))

Hrqls: These are the GnuBg rollouts. According to these, making the 2-point is a doubtful move and the standard drop-and-split is the best for the non-gammon situation and second best even in gammon-save! But in the gammon-go situation the 2-point comes to the fore.

Double match point. Gammons don't matter to either side.

#. Move _________ Win __ W.G __ W.Bg __ Lose __ L.G ___ L.Bg ___ Equity
1. 24/18 13/9 ____ 50.9% _ 20.6% _ 2.7% ... 49.1% _ 19.7% _ 2.8% ... +0.018
2. 24/14 _________ 50.5% _ 17.1% _ 2.5% ... 49.5% _ 17.4% _ 1.9% ... +0.010 (-0.008)
3. 8/2 6/2 _______ 49.4% _ 22.5% _ 3.6% ... 50.6% _ 18.9% _ 2.0% ... -0.012 (-0.030)
4. 24/20 24/18 ___ 49.1% _ 17.5% _ 2.0% ... 50.9% _ 18.8% _ 2.3% ... -0.019 (-0.037)
5. 24/20 13/7 ____ 48.9% _ 19.0% _ 2.4% ... 51.1% _ 20.1% _ 3.3% ... -0.022 (-0.040)

Error: ___________ 0.3% __ 0.6% _ 0.3% ..._ 0.3% __ 0.6% _ 0.4% ..._ 0.006


1-away, 5-away. Gammon-Save for the leader.

#. Move _________ Win __ W.G __ W.Bg __ Lose __ L.G ___ L.Bg ___ Equity
1. 24/14 _________ 50.1% _ 19.5% _ 2.9% ... 49.9% _ 13.1% _ 0.3% ... -0.202
2. 24/18 13/9 ____ 49.7% _ 21.0% _ 3.3% ... 50.3% _ 13.7% _ 0.4% ... -0.222 (-0.019)
3. 8/2 6/2 _______ 49.3% _ 22.4% _ 4.0% ... 50.7% _ 14.0% _ 0.5% ... -0.235 (-0.032)
4. 24/20 13/7 ____ 47.9% _ 19.4% _ 2.6% ... 52.1% _ 13.0% _ 0.4% ... -0.249 (-0.046)
5. 24/20 24/18 ___ 48.6% _ 18.2% _ 2.9% ... 51.4% _ 14.1% _ 0.5% ... -0.253 (-0.050)

Error: ____________ 0.2% __ 0.6% _ 0.3% ..._ 0.2% __ 0.2% _ 0.1% ..._ 0.006


5-away, 1-away. Gammon-Go for the trailer.

#. Move _________ Win __ W.G __ W.Bg __ Lose __ L.G ___ L.Bg ___ Equity
1. 8/2 6/2 ______ 50.3% _ 15.6% _ 0.4% ... 49.7% _ 18.3% _ 2.5% ... +0.245
2. 24/18 13/9 ___ 51.2% _ 13.0% _ 0.4% ... 48.8% _ 20.6% _ 2.3% ... +0.231 (-0.013)
3. 24/14 ________ 51.1% _ 11.4% _ 0.4% ... 48.9% _ 19.5% _ 2.1% ... +0.207 (-0.037)
4. 24/20 13/7 ___ 49.5% _ 13.1% _ 0.5% ... 50.5% _ 21.3% _ 3.8% ... +0.198 (-0.047)
5. 13/9 13/7 ____ 48.5% _ 14.1% _ 0.4% ... 51.5% _ 23.2% _ 4.9% ... +0.190 (-0.055)

Error: ___________ 0.2% __ 0.2% _ 0.1% ..._ 0.2% __ 0.6% _ 0.4% ..._ 0.006


Full cubeful rollout with var.redn.
1296 games, Mersenne Twister dice gen.
Seed 985902322 and quasi-random dice.
Play: 0-ply cubeful prune [expert]
Cube: 0-ply cubeful prune [expert]

(I made a mistake when doing the gammon-go rollouts in that I forgot to set the Crawford-game flag. It's thus calculated as if the cube were live for the trailer. But that's fair enough if you think of it as a 7-pointer and the trailer has won the Crawford game.)

grenv: what about 24-18 and 13-9 ?

Pythagoras: With 6-4, making the 2 point is a good play in any situation, though 24-14 is just as good usually. While going for gammon the 2 point should be made and while saving a gammon 24-14 is correct, but the cubeless equity of either move is about the same I think.

Pythagoras: No, I didn't correct my "mistake", lolol.

I anticipated (nay, hoped for, lol) a wee bit of discussion so I plugged in a qualifier.

I wouldn't say that playing for gammon means a significant difference strategy (though, of course it depends on what makes for significance).

I guess we differ if what we see as significantly different. I picked the game up again a couple of years ago at VogClub. I must admit that gammons were part of the game right from the start - whether played without the cube (first 12 months or so) or with (thereafter) - so my play is more gammon-centred than it would be if I'd been playing here. I do often play for gammons even when not necessary because that win is a thrill and so worth the risk of losing the point. (That's obviously not a good tactic for serious tournament play, so it's a good job that I don't play serious tournaments!)

But when I do play without needing a gammon then it's not a significant difference in game play. There are some differences in the opening moves (though 6-4: I'd make the point in both gammon-go and gammon-save) but the majority of the game is the same for gammon-go and gammon-save. You might have "Gammon..Gammon..Gammon" running in your mind the whole time but it may not be obvious on the board. Closing the home board is always a priority and needs those builders, double-taps are a joy in many occasions (though sometimes a foolhardy one, lol). To me it's more a toning down of aggressiveness and less risk taking. A shift in emphasis towards the race and away from the battle. But, like I said, my base level is perhaps already more gammonish than others.

We're talking about the same things here yet while Alan says "significant difference" and you say "very different", I say "tone down" and "shift in emphasis".

playBunny: Gammons are part of chequer play while I'm used to having the cube as a separate deal. I wouldn't say that playing for gammon means a significant difference strategy (though, of course it depends on what makes for significance).

Oh no.....You've disappointed me! But hopefully you corrected your mistake at the last moment....
Of course and game play is very different when someone plays for a Gammon. Even from the start. Trying to close his home board from the beginning, slotting like a maniac(well the maniac goes in desperate situations), playing very aggresively, bringing builders targeting at the home board, double hitting in almost every chance, not paying big attention to splitting, etc.
For example when you are going for a gammon and the start play is 64 then you just make the 2 point! This would be correct in this situation. 43,32 starting rolls call for bringing 2 builders from 13. Even when the opponent starts with 43 and plays both from his 24-point, and then you have 32 for example, a double hit is probably the best move in a go-gammon situation....Also 21 with slotting, although this is considered superior in no gammon-go situations too, 51 with slotting, etc.....

redsales: correct

back/gammons still don't count for cubeless games, do they??

grenv: True, but that's a lame excuse. ;-)

Thad: Hear Hear. I guess it's part of the game engine for all games though.

alanback: Which makes me wonder if there should even be a draw button in backgammon games. Pente is the same. Matches can be draws, but not games.

Pythagoras: It's true draws are theoretically possible, but only if both players agree. Theoretically, again, that should happen so rarely that it is not necessary to consider the possibility of a draw in discussing backgammon.

alanback:
I don't think there is a difference, is there? There is a difference for games where draws are possible. If draws were possible, then each player would earn half a point toward the 10 point goal in a draw, but draws would not count for anything in a 10 wins match.

But draws in Brainking Backgammon are possible.....
So a 10 points match is different from a 10 wins match....

Imagine the following:

Situation-1
----------------------
----------
At a 10 points match:
Player-1 = 18 draws + 1 win
Player-2 = 18 draws
Player-1 wins!
----------------------
At a 10 wins match:
Player-1 = 18 draws + 1 win
Player-2 = 18 draws
Nobody wins yet! Score is just 1-0 for player-1. Player-1 has to win 9 more games in order to win, while Player-2 has to win 10 games....
--------------------------------

Si

tuation-2
--------------------------------
At a 10 points match:
Player-1 = 2 draws + 9 wins
Player-2 = 2 draws + 5 wins
Player-1 wins by 10-6!
----------------------
At a 10 wins match:
Player-1 = 2 draws + 9 wins
Player-2 = 2 draws + 5 wins
Nobody wins yet! Score is 9-5 for player-1. Player-1 has to win 1 more game in order to win, while Player-2 has to win 5 games....
--------------------------------

So there is a difference.
What i am missing.....?

playBunny: I stand corrected!

alanback: It should never appear routine.

grenv: Comedy should never be routine

grenv: Heh heh. My best is only viewable in the fellowships.

playBunny: You'll need to improve your comedic routine before you impress me.

alanback: (Obvious line.. ) I've already gathered that impression. Boom boom.

playBunny: What if I'm an impressionist?

alanback: I think of gammon and the cube as part of the package.

Gammons are part of chequer play while I'm used to having the cube as a separate deal. I wouldn't say that playing for gammon means a significant difference strategy (though, of course it depends on what makes for significance). I think it would be an interesting enhancement to non-cube matches without being alien territory to non-cubists.

Marfitalu: That's my understanding.

Marfitalu: Well -- I think of gammon and the cube as part of the package. Of course, it would be possible to count gammons and backgammons in multiple point matches, but it would be odd. If there's no cube, I am used to the idea that I am playing for one point only. There is a significant difference in strategy.

alanback: You are right, of course! I stand corrected.

txaggie: It makes very little sense to count gammons in one-point matches or matches without the cube. It's rarely done, and it isn't done here.

alanback: Lol. I was having second thoughts even as I posted, so I just did. My reply's been deleted.

playBunny: You need to go and read the description of a 10 points match! This is not a 10 game match, but a match to 10 points.

alanback: Marfitalu: Isn't the answer that even without the cube, you can score more than one point in a single game of a multi-game match? If you reach gammon or backgammon against your opponent, you would get 2 or 3 points for the game, instead of one point. So, it is possible to reach 10 points in fewer than 10 games.

Marfitalu: I don't think there is a difference, is there? There is a difference for games where draws are possible. If draws were possible, then each player would earn half a point toward the 10 point goal in a draw, but draws would not count for anything in a 10 wins match.

ZEROZERO: Curiosity, not suspicion.

I can understand that frustration as I get periods of play like that against a robot that I play at a different site. I'm glad to hear that nobody25 spotted the "madness" and you had a chat.

investigate what other players are doing here ...

Aye, there are a number of players who do that. It's not investigation as such because usually it's stumbled upon and then brought to the board (specifically as suspected cheating not, like in this case, as an interesting happening). That can only be a good thing because there are cheats who have been exposed by the "investigators".

...But oh well...everybody has the right to do here what he(she) thinks is fun.

Looking at the graphs, rating lists, reading other's profiles, going through games. Oh yes, that's definitely part of the fun!

LOL...didn't know we were that interesting

Thanks for enlightening us, it was interesting! And you write with good humour.

I hope your illness isn't too much hassle and you get better soon. Sounds like you'll be able to make a bit of holiday out of it. Have fun, too!

I'm enjoying being #1 in two gammon variants at the same time, as I did when I was #1 in BG -- but I don't expect it to last!

nobody25 and Zerozero: ..i agree 100%..the problem is that some of the "top players" are taking the rating much too seriously.

nobody25: *nod* true .. handled personally is always better, especially with rooks who are often on the site and are known to answer

i didnt even know you were #1 for a while :) fun :) it only happened once to me .. not in a gammon type though but just when espionage came online, i was one of the first to complete 4 games :) .. yes never been #1 established .. but i am working on my gammon skills lately :)

playBunny: You know I don't post here or on general boards often. It looks to me you were the one that brought it up. The others just carried it on.
Just to let you know...I don't have a webcam. All I do is talk..LOL

you know, if i saw someone rising that fast i would go and see for myself, but not bringing it up on a board like this. ZEROZERO resigned all those games when i wasn't even online, then i came online and asked him to stop, oke it was fun to be number one, but i play so much hypers, that in a few days i will probably go down fast, and i really don't care about those ratings, i just love playing those games, and that's it, but i rather prefer that if anything like that happens again, just send me a message and ask me what is going, so i can explain, rather that, then now, hearing that you were talking about it, about the games and me, and i have to find out trough other people.
I'm not mad or anything, and i will keep playing everybody, but next time, just send me a message, please, or if you wanna say it here, just let me know, and not like this.
Thanks, peter, and hope to see you all in some games, you can play me, and try to get my rating down, lol

alanback:

ZEROZERO: some players show weird patterns, have a look at some of the top players of hyper gammon .. i dont think there are any weird ones up there now .. but now and then a new player (often pawns) shows up in there with very weird games (often a lot of resigns by his opponents, which are also pawns, in games which the opponent would have won) ... some people look at the top ratings to have a look who are moving up the ranks and who arent .. and to study their games to see if they can learn anything new from them and to challenge them for an interesting game themselves

i know both you and nobody from several games and know you arent cheating (at least i wouldnt expect you two to do :)) ... but curiousity is a characterstic of humans which cant be denied ... even though it wasnt cheating i was curious to what happened myself as well :)
not thats its a matter of life or death to me .. but something which can make one curious (and that doesnt have to be a bad suspicion)

(sorry for the wrong english words :))

ZEROZERO: Nothing kinky, please, I have a weak heart

alanback: wow ...I didn't know that you people were "spying" on players moves and profiles and stats and whatever ....feels like " Big Brother" LOL..maybe Peter and I better put our wabcams on when we are playing so everybody can watch us doing strange things ROFLOL

playBunny: It certainly was a curious pattern, and brought out my monkey curiosity as well :)

playBunny: indeed I wouldn't know how we could cheat on whatever by resigning a few games (read : a lot of games) and winning a lot of games a few days later