The Czech version is stricter:

1. NO CHEATING. This term includes making use of external programs for suggesting the best moves and deliberate losing in order to increase the opponent's BKR. Such behavior, if proved, may lead to the account blockage and removal of the BKR from the ratings table.

I wonder what the esperanto version says

Pedro Martínez: I thought I had seen where Fencer said he was going to change/update that part and he didnt think that programs were useful in dice games. It sounded like he didnt care if they were used.

Nonsense, if the dice roll can be entered by the player then clearly a computer could assess the best possible move. That would only apply to games where luck was everything.

If your opponent agrees to the use of a program then it would be okay. "Cheating" should be defined as the (surreptitious) use of such programs with intent to create an unfair advantage. I can't see many players agreeing to the use of programs.

I made a post on the brainking.com board (Re: Backgammon Programs, 8. June 2005, 01:39:07) which included thoughts about cheating with a bg program. :
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The opportunity to cheat [with a bg program] is immediately obvious - you only need enter the current position and dice roll and ask for the moves. A successful cheat would not play an entire game according to what the machine said but would only use it to advise in tricky situations. In other situations it would be possible to pick the 2nd or 3rd moves, even 7th, etc, if they were not desperately worse than the best. This makes it somewhat difficult to detect a cheat.

In practice, however, if you examine the games of the top players at most sites, you will find that even the best will make bad moves and even huge blunders - as judged by the program. These programs are very exacting judges. The player will sometimes be able to argue why their move is good but more often it will be recognised that the move was indeed a poor one. This makes it somewhat easier, then, to detect a clumsy cheat. [That's in general, though. For Fencer to detect backgammon programs would be impossible as he would have to analyse everything. It takes several minutes per game and that's computer power which is not available - nor, if it were, would it be very productive use of his servers.]

Using a computer when playing against a robot is hardly cheating but when playing against other people it certainly is - unless there is disclosure and acceptance beforehand.

What about using the computer to analyse a move after it has been made? A main reason to do this is to maximise learning while that move is pertinent in the mind. The aim is to improve your play in future games by recognising the type of position and/or knowing how to act given a particular dice roll - building one's intuition or heuristics. But is it cheating, even if not as obvious as examining a move beforehand?

Well, it will have no effect on the game in some situations but in others it will. If you are attempting to trap a piece behind a prime and have been concentrating on adding a block at the front, but the bg analyser marks your move down because it reckons that you should have been trying to close the rear end first, then your next moves will be influenced as you change your plan. The computer's analysis has suggested a tactic in an ongoing situation - and therefore been of benefit even though used in retrospect.

On the other hand there are very many situations, especially at the start of the game where the volatility of the position means that tactics must be kept very fluid and every position examined as if the game were starting from there. In those situations the use of the computer would not be of much benefit in the current game.
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So, if you want to use your program, you should be aware that analysing the game after each move could still give you an advantage and this would be unfair if such usage is not disclosed. The best way to use a bg program is after the game has finished.

The same judgements could also be made if you use this board to get other people's opinions about a game while it is still in progress. Although this would be very visible to your opponent if they were a reader of the board, it could be seen as cheating.

playBunny: the most fair way to use a bg program would be to play separate games with it and analyse those .. nothing connected to the site, the games on here, the mvoes done, the dices rolled, etc.

keep it separated and there will be no problem at all .. you will just train yourself by playing with a nice teacher

Hrqls: There could be no disputing such a stringent delineation. Yet I see no problem with analysing a game that's finished. I'm wondering, then, what advantage there is in denying yourself the analysis of a BainKing match. In fact I've done just that with a game against Walter. It brought me into a game situation territory that I only rarely get into and, to me, it was an opportunity not to be wasted.

playBunny: I won that game. Knowing the dice guy is more important than having a machine. Are you ever going to learn how to roll a four? :) That was amazing in its luck (bad) to have happened.

Of the three games we played, that was the only that had all them blots getting hit. At one time we had more men in the opponent's home base than in our own. :) In that game, does this machine say I played badly and got lucky or played it well and took advantage of good dice for me and bad for you? Or does it say something else?

Walter Montego: Do you really want me to say here? lol. The program graded your play as "Beginner". It is a very harsh judge, though, and all of the top players whose games I've analysed get "Awful!"s and "Beginner"s as well as the "Expert"s and "World Class"s. ("Top players" doesn't mean world-circuit top players, but those at the sites at which I play).

I've made my GnuBg stricter on evaluating individual moves than the standard version (so, for instance a fairly good move on the standard is a Doubtful move on mine, a Doubtful on standard is a Bad move on mine). On that basis you got 6 Doubtfuls, 2 Bads and 1 Very Bad. (Standard settings: 2 D, 2 B and 1 VB)

The two Very Bads were failures to hit blots. The two Bads were both doubles (a 4-4 and a 5-5). It's a surprisingly common error. Many of the games that I've analysed show good play apart from a failure to take the best advantage of doubles.

The bad luck that Walter is referring to is me being hit and sent to the Bar 11 times. And with that last hit I was on the Bar for 13 straight rolls despite the 4-point being open the whole time. Odds of 10,000 to 1 or something. Walter was very hospitable though, and I got very drunk for free in his bar. ;-)
Walter vs playBunny

All that being hit forced my own play somewhat and I made 1 Doubtful move and 1 Bad one. Overall I was judged as "Advanced" (which is the category below "Expert").

Revenge is not happening yet, either, as that dice guy is still working overtime creating doubles for Walter, lolol. He won our last Best of Three and is looking to take this next set, too. [I say that hoping to provoke Fate into doing something before it's too late. ;-)]

playBunny: Hard to imagine this machine saying my failure to hit a blot is a bad play. I think I hit too many blots in games and leave myself open for lots of trouble. Which move in the game is that, or is it the only time I didn't hit your blot when I was able to out of 12 times?
Does the form of Backgammon that we play have anything to do about these assessments the machine spits out? Single game strategy is different than gambling for money and that's different than playing a set match. And then there's the way that I would play, just a series of games counting gammons and backgammons but no doubling cube.

Walter Montego: The first was move 6 and it was hitting the wrong blot. Should have been hitting on 11 from your anchor on my 5-point. I guess you didn't want to break that anchor?

The second was move 19. Again it looks like you didn't want to bust that anchor. You came off the bar and sent the man out missing my two blots. He got tapped on the head for being nice! ;-)

Walter Montego: Does the form of Backgammon that we play have anything to do about these assessments the machine spits out? Single game strategy is different than gambling for money and that's different than playing a set match. And then there's the way that I would play, just a series of games counting gammons and backgammons but no doubling cube.

I believe that the PlayBunny took into consideration, what kind was the game (single or not etc...) for making his analysis with GNUBG. The results and the suggested better moves are very different of course if the game is a single one and it even depends from the current result of the match (In a single game of course is 0-0)........

playBunny: I think my move on turn 6 is better, but I can't say why. As for the other turn I suppose that other move was available, but I don't like giving up advanced guarded points in my opponent's home base while leaving everyone as a blot to get messed with.

As I say, "Luck beats skill."

So I won the game despite playing poorly, or am I better player than you and this machine doesn't know what it's talking about?

What are plies? One person's turn, or both players making a move? Or something else? You say the machine only thinks 2 plies ahead? I think lots further ahead when I play Backgammon. Leaving blots or missing them on purpose can be arguable as to which is the right thing to do at that time as compared to the long run, but in a individual game the dice are rolled now and you get what you get. The very first moves of a game are argued about in some cases! The starting position hasn't changed in over a hundred years and yet experts will still debate about what to do in some cases. Even a roll of double fours as player two's first roll has debate about it. As for later in the game, I can see experts debating the merits of a particular style or play. How does the machine come up with its recommendations? You did some explaining earlier on the BrainKing discussion board, but someone had to write down for the machine how think about going for the win. Let alone how it would dispense advice.

Do these machines ever play against each other? I've heard some of you guys saying they've played against people and have done very well in recent years.

Chessmaster1000: That's a good point, most of the time these programs will calculate expected result, meaning they will double the number of gammon chances etc. In this site we should only be worried about winning %ages.

Walter Montego: I'd have to disagree, your move 6 should have captured the 11 blot in my opinion. For one thing your chance of being hit next turn is less, and you knocked back his piece further. Easy in hindsight though eh?

Walter, CM100: First off, sorry for missing that bit about the game properties, and thanks for answering it George. (And yes, I analysed it as a single-point match.)

Much of my learning with GnuBg has been of the form: do a move, get told off about it and then, in the absence of any verbal explanation from the program, rationalise the moves that it says are best. Often this is helped by the fact that there will be part of the move which is common in all the top moves, eg getting a backrunner moving or making a point.

That move 6. The best move given by GnuBg was to hit on the 11 as I said. The second was to bounce off the bar to 16 and start getting home. Your move was deemed 5th out of the 6 that were possible. Guessing to the utmost I think there are several factors. Your move hit on the 2-point in your table which is deep. GnuBg doesn't usually care to go deep. And the hit gave no particular advantage given that there were 5 points open. It even thought that simply moving your blot from 10 into 4 would have been better. More importantly, I think, it wasn't comfortable with you having 5 men in my home table. You had anchors on 4 and 5 so one of these is superfluous. the 5-anchor is better, of course, but hitting me on 16 would have started you on the way home and evened the pipcount by 14 reducing my lead to only 10 pips.

Damn right with "Luck beats skill". It takes a lot of skill to overcome a little bad luck and a little luck to beat a lot of skill. ;-) That's very apparent from having watched so many tournaments at VogClub (they're over in a couple of hours). The top players win more often, of course, but they frequently go out to some of the weakest players.

The Backgammon Rating Formula as used by most of the bg sites calculates that top players (2100-2200; the maximum is lower than in the chess system) playing an average player (1500) will actually lose about a third of the individual games played. That indicates how much luck the formula reckons to be in the game.

I think we'd both agree that you won that particular game due to luck. All those hits and me dancing for half the game while you romped 5 men back from my home table without a care in the world?!! Lolol. I was looking forward to a good jousting match between our respective knights but your knights snuck home in the dark of the night while my King was getting drunk.

As for who's better? Time will tell, my friend. You have the lead so far. ;-)

But does this machine know what it's talking about? Well there are certain games plans/styles/situations where it is less accurate than others - mainly because they are less common. Back games and near back games such as ours may well be in that category; certainly it was true in the past, but the databases improve with every release. I don't know enough about that area to state much.

They do play each other. There's a program vs program tournament held every year but attendance is dropping as it's expensive to enter and the existence of GnuBg as a world-class and free program means that revenue has dropped for the professionals.

Plies: These are single moves (replies). Gnubg was written by a computer scientist and it starts counting at zero. [rolls eyes + shrug]. So at 0-ply it is considering all the moves that it can make with each of the 21 possible rolls. 1-ply is the player's responses and 2-ply would be GnuBg's replies to those, etc. However a ply isn't quite the same as thinking ahead in chess or as we would think ahead.

You may remember me saying that the neural nets work by amassing huge amounts of statistical data. That data allows it to say with some degree of accuracy that getting to a particular board position gives a certain winning chance. In that sense it's actually "looking ahead" from that position to the end of the game. This evaluation isn't perfect, however, because perfection requires the right values for all the possible board positions - and that's just too much. The reason that neural nets are used is because they are the best mechanism, so far, of making good approximations for data of this nature. Like us they can look at a pattern and say "hmmm, that reminds me of something very similar, I'll use that as a guideline" except that they are geared to look specifically at backgammon patterns, and can do so with great accuracy.

The way plies work is that they take the board further towards the end of the game where these estimations are (generally) more accurate. It's a bit like running to the top of the next hill and the next to see what's out on the horizon.

Ideally the program would always work at 4-ply or better and calculate every possible roll and every possible move at each level. There are 21 possible rolls and anything from zero to umpteen moves (me's no computer, lol) at each ply. This degree of "branching" is much more than in chess and the reason why chess programs can look ahead further; the processing required in backgammon, even at 2-ply, is huge. In order to cut down on the processing and maximise looking ahead, the bg programs utilise a filtering system. The initial 21 rolls are always considered in full. (This is 0-ply). The worst moves are discarded and the remainder examined for responses to the next 21 possibles rolls. (1-ply) The top moves are kept and the next ply examined, and so on. (This, for those who have recently acquired GnuBg is what the filter settings refer to).

At each level, and for each roll and possible move, the board is evaluated. The board evaluation isn't done in a dumb sense of just saying how many pieces are there on each point. This will only be possible when a database can be constructed which holds every position in backgammon (about when "Beam me up, Scotty" is possible). Instead the program does what we do - it consider what elements are present: how many blots and points made in each home table, how many points made in the outer field, is there still a midpoint, how many spares are there on the points, how many builders are there and where, how many runners, what's attacking what, what is the balance is across the board, is there still contact, is there a prime, a broken prime, a closed table, etc, etc, etc; whatever the designers can think of. These elements are what the neural net considers when it's looking for patterns (and partly what makes the differences between the programs). Then, the statistical weightings that it has generated from the thousands of games that it's played against itself say that a given set of positional elements (or, more likely, a set with a given (and high) degree of similarity) has been found to produce a win in such and such a percentage of the games that were played from that position.

Because the winning chances for these positional sets are determined from self-play, you can imagine that situations that turn up again and again will be more accurate. This makes sense as it is the same for us, too. The "degree of similarity" of the set of position elements will improve, approaching an exact match, and the number of games that have been played from that position will be higher too. The quality of the bg programs is still high in the lesser known positions, however, simply because the programs get to discover and play through a lot more of them than we do. A well designed bg program will seek to ensure that the bg "state space" is explored adequately.

Using self-play has an interesting aspect. The evaluation of any position is based on the premise that the opponent is as good as the program. The moves made will thus be on the assumption that the responses will be "perfect" and the program will do its looking ahead amongst the best moves for each side. There is an occasional advantage, then, in playing the unexpected dodgy move because you will be leading the program along a game path that it might not have considered (having filtered out that move and path as being too poor). But making poor moves in order to fool the program may lose more than is gained, simply because they are poor moves. [Ignore this paragraph if it comes across as confusing. ;-) Hey, ignore the whole article! ;-D Lol]


Hopefully you can see that at the furthest extreme it's not even necessary for the programmer to know how to play backgammon! They can simply encode every possible board position and assign it the results of playing every possible game. Hey presto - the perfect robot player. This has in fact been done for hypergammon and for the ending positions in backgammon (the bearing off stage). The robots can play these absolutely perfectly with no consideration required other than looking up an exact board position. The next stage will be to encode every non-contact position (all my pieces have passed all yours, let's race) but that's still too big a number of positions to calculate and store.

The current situation is that a neural network can evaluate game situations by recognising the mix of positional elements. The programmer can easily code for these elements without being too good a player (although, in practice, the advice of top players has been readily utilised). The programmer isn't telling the robot how to play, however; he's telling it what to look for when considering how to recognise game situations. And it's the statistics of how many wins were produced from each game position that was met in the course of self-play that tells it what to play. The bg programs can only teach by saying "here's my list of moves"; they still don't really know much about how to play, lol.

Hope that was useful. :-)

playBunny: thanks! that was very useful :)

i will play a lot more against gnubg (i already notice some changes in my play .. i now know the 5 pnt is very important .. and i dont go too far into my home at first (i noticed as well gnubg didnt like that in the analyses)

what is superfluous ? i thought it was always better to have 2 anchors directly next to another instead of just 1 ? it improves the chances a lot in the end (when you are not ahead in pips)

I don't understand. I thought it must be very simple to count probability using brute force analysis, so why to use neural networks or statistical analysis for backgammon?

Chess:
1 move has about 30 possible ways to play.......

Backgammon:
1 move has about 21·X possible ways to play........
This X is about 8 to 40 and depends on the position. For looking 8-plies/4-moves ahead it would need for X=35(in a simple middlegame position):
(21·35)^8 = Oh my God!
So no minimax or alpha-beta would help.........

Note:
21 is the number of different possible rolls.
X is the number of different possible plays for a single roll of the possible 21.

robos trying to imitate humans are still understandable
while humans somersualting after machines seem a bit silly ... ~*~

My pet peeve on this site is players who achieve a ridiculously high rating in just a few games (I still don't understand how the rating system allows that to happen) and then just sit there refusing to play more games. I have had a challenge outstanding with the #1 ranked nackgammon player for months with no response. He is not obligated to play me, but I think he should be obligated to play someone and defend his position. A very high rating based on a limited number of games is not an accurate indicator of ability in any case. Some system should be devised to prevent players from sitting forever at the top of the ratings without playing. Perhaps they could be moved back into provisional status if they don't finish a game in a given timespan (such as two months).

alanback: I'm sure I read on another board that Fencer is addressing that problem and that something along the lines of what you suggest is to be implemented.

bumble: Yea, Fencer talked about it - not sure how high it is on his list. Something like removed from the ranking list after 2 months (Pawn) or 3-4 months (Knight & above) - or something like. Of course play one game, and back on there - but at least keeps the player active a little bit.

BIG BAD WOLF: Why not change the ranking so that only games completed in the last 6 (or maybe 12) months are included in the rankings - then we would get a better idea of current form, scores gained "learning" games would eventually be eliminated, and the peeve would eventually disappear. (anybody without sufficient completed games in the chosen period could revert to a provisional rsnking)

pgt: That is an interesting idea I have not heard before, and it seems like it could be an good idea. Will have to think about that some more.

pgt: I've heard it said that on FIBS, your rating is pretty much determined by your most recent 400 experience points anyway. So, why not base ratings on that?

alanback: You need to read to the original post on the subject - the peeve concerned players achieving a high rating and then refusing invitations to continue playing. Hence the "elapsed time" suggestion.

pgt: Certainly worth considering. For those of us with paid subscriptions, it would not be a hardship; but Pawns who play a lot of different game types might find it hard to keep up.

what about ladders ?

each player holds a position on a ladder, lower players can challenge higher players, they have to accept (or drop a bit on the ladder) ... the outcome of the game (if accepted) calculates the new ladder position for both players

it would introduce a new system next to the bkr .. and i am not sure if fencer likes this ... but it sounds interesting

in active players would drop because they dont accept the challenges

of course this will be tough for the top player because he will receive a lot of challenges which he might not be able to accept (because a person can only play a limited amount of games during a certain time)

Hrqls: There have been long conversations about ladders on Features and other boards.

Ladders will be implemented at a later date.

bumble: ah nice! it will be fun i guess :)

alanback: FIBS uses a backgammon formula which is used on many sites. Like the chess formula that is used here, it encapsulates the entire playing history. The 400 figure that you're remembering is used when a new player is establishing their rating. For the first 400 experience points the amount gained or lost by a match is multiplied by a number proportional to how many of the 400 points are left. The multiple is 5 at the start and 1 by the time the player has reached 400.

I also don't care to see the same 6/0/0 at the top of the rankings table. Perhaps the cocktail has lost his bottle? I like pgt's suggestion of using a limited history but it might be expensive to administer. A reasonably easy to write method would be that the ratings are recalculated every day for every player (and presumably for every game type). I don't know how much server time that would take but it would certainly be a growing amount as the site gains in popularity. Doing it monthly would be a reasonable compromise; a different set of players could be done on each day of the month.

should be only an additional value - why punish serious players who play continuously ?
irrigardlessly a penalty rating for inactive players seems reasonable after a while,
let's say 100 down after 3 months not giving a flying stuff at challenges ... ~*~

playBunny: The observation I referred to was statistical -- I can't prove it, but the point was that any history more than 400 experience points old had little effect on your rating -- I think we have all experienced how ratings can swing. If you've been winning recently, your rating is relatively high; if you've been losing, relatively low; it doesn't matter much what it was this time last year. This is different from the 400 points needed to get past the "newbie" factor, of which I am also aware.

alanback: The problem is that building this into the formula doesn't have any effect on those that choose not to play at all.

If there was some way to penalize not playing, perhaps some sort of natural decay could be built in to the rating.

Alternatively just remove players who don't either start or finish a game in a set period (I suggest 3 months). If they play again after that they get a provisional rating again.

grenv: hmm .. nice idea! .. a half-time (dont know the english term, in dutch its 'halfwaarde') like in radioactivity :)

Hrqls: half-life (german: Halbwertszeit)

Luke Skywalker: ah yes :) i forgot .. thanks :)

for the hide function protecting me from the sillliest ideas after all ... ... ~*~

danoschek: Thanks for pointing that out, I can hide that crazy German character now ;-)

aware of all those normal and self-declaredly reasonable default characters ... ~*~

I don't really have a problem with players deciding to rest on their laurels. The problem is that their ratings are unrealistic to begin with. As has been said many times before, the rating system here is not suitable to the gammons. FIBS works well at dailygammon and GT. It is a simple formula so why can't we implement it here. If someone leaves with a high FIBS rating at least you know they earned it.

Mike UK: Do you understand the two rating systems well enough to explain the differences? I thought they were basically the same, but clearly they are not.

alanback: I think the underlying theory is similar in both systems, but in practice they behave very differently. First of all the parameters in the USCF formulae are set up for chess and are not suitable for games like gammon where luck plays such an important role. Secondly the provisional formulae are designed to allow a relatively small number of new entrants to quickly reach their correct rating in a large established pool of players. When applied to a startup situation they just introduce a random element. Similarly the formulae for established players only work in a mature rating system. So even for chess, the rating distribtions here are nothing like those of the USCF itself. You only have to look at the number of players here who achieve the rating ceiling of 2700 to see this. At times it seems that ratings are just proportional to number of games played.

As you know in FIBS everyone starts at 1500 and have to work their way up (or down) the ratings over the course of at least 400 games. Because of this, nobody gets a high rating by luck. By the very nature of gammon, it is impossible to try and get to a realistic rating playing less games than this.

The USCF itself uses a different rating system for correspondence chess which I believe is a lot like the FIBS system. I think this would be the obvious one to use at a site like this for chess and the other games. Again probably without the provisional formulae.

Mike UK: I've always been concerned by the fact that after a while I tend to just go up or down 8 when I win or lose.

The problem here is that if I am even a little above average and win, say, 55% of my games, I will eventually move my rating up as I play a lot of games.

What is wrong with my reasoning here?

grenv: Your observation seems to be correct as long as the opponent is within 400 points of your rating. If the difference is greater than 400 points, then you will be penalized heavily for losing while gaining very little if you win. This is why I try to limit my opponents to those within 400 points of my rating.

The chess formula is based on single games where skill is the only factor. A player deemed better than another is expected to win by skill alone and the gains from winning are meagre and the losses from losing are punitive for the better player when the difference between them are large.

In the chess formula, a rating difference of 400 points favours the expert who is expected to win 9/10ths of their games against the average player. In the backgammon formula, the effect of luck is such that experts (500 higher than average) are expected to lose in the region of a third(!) of games against an average player. The losses and gains are much less per match to account for this luck effect.

In chess I believe you play only single games and each game is worth 1 or 1/2 a point whereas in backgammon there are matches worth multiple points. Though the expert backgammon player is expected to win only 2/3s of their single games against an expert, in an 7-point match that goes up to around 80%. So an expert is expected to win a decent length match but the chances of the beginner's lucky win are by no means negligible.

Chess maxes out at 2700 or something, with backgammon 2200 is unusual.

More info:
The US chess formula

Rating calculator for backgammon
Complicated looking but also informative.

Press the [Newbie] button (it uses 1600, not 1500) and the [500] button and look at the percentages in the first table to see that the expert, P2, should only win 64% of single games but 82.1% of 7-point matches and 90.3% of the 25-pointers.

alanback: absolutely correct. a diligent player (stable rating)
won't lose more than 8 points to an opponent withing the 400 points range ... ~*~

playBunny: In chess I believe you play only single games and each game is worth 1 or 1/2 a point whereas in backgammon there are matches worth multiple points.

It's not as simple as that. The chess rating system works just fine over longer matches - in fact, it works even better. If the real rating of two players would be known, one could calculate by which margin a player would win (or lose). For instance, a rating may predict that one player would win 65% of the games. Obviously, this would never be possible in a single game (the score being one of 0%, 50% or 100%), but in a 10 game match, it certainly is possible to get 65%, or at least get closer to it than 50%. In chess, if players play a match of more than one game, or even a complete tournament, ratings aren't adjusted game-by-game, but the result of the entire match or tournament is used. So, if you play a match or tournament, and according to your rating, you should score 58%, but you only scored 45%, your rating will drop.