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Backgammon and variants.

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14. април 2009, 10:20:20
Constellation36 
What's the purpose of writing a rule of a game when the system does not apply it?

Look at this move White to play 65. White is forced according to rules to unblock a point in the 6 prime to allow an opponent to move.

This is the corresponding rule Brainking has:
It is allowed to build a prime (six consecutive blocked points) anywhere else (not in the player's starting quarter), but if opponent has collected all his checkers onto the one point behind player's prime, the player must unblock a point in his prime to allow the opponent a chance to move.

The implementation has also another serious flaw.
I will make an overview in some days about what improvements need to be made in Fevga in this site, to the rules and to the implementation that is buggy.

9. февруари 2009, 19:35:39
Constellation36 
Относно: Re: Backgammon rating cheats
Променен от Constellation36 (9. февруари 2009, 19:36:17)
playBunny:
Yes as i see the rating system is a tragedy indeed. Among others it highly overestimates the starting games to establish an ELO.
If you have accidentally or not some good starting results, in the starting 4-6 games e.g then you get very high ratings that are hard to decrease too much and indicate your real ELO.
On the other hand if a good player has a bad start he has to suffer and wait many games in order to take his real place.

Also the way Chess variants' and Backgammon variants' ratings are handled should definitely not be the same as they are.

Some more problems are that this site unfortunately is full of players who try to be smart not to say smarta***
They take advantage of some games that favor one side and play always with that side and getting placed at the first places of the ratings.
E.g Horde Chess, Maharajah Chess and some others as i've seen. I wonder what's the meaning and the purpose of doing this? This ain't no fun!

And what about this Maharajah Chess game? This game is so one-sided that black wins hands down. What's the purpose of still having it? Even if white had 2 Maharajahs black would have a forced win again.

Some things are hard to understand to this site.

9. февруари 2009, 19:14:46
Constellation36 
Относно: Re: Backgammon rating cheats
playBunny: If all these happen then why the site owner does not do something to clear his site from all these morons?

He isn't aware about this or he is but he just hasn't enough proof for taking action?

9. февруари 2009, 18:45:47
Constellation36 
Относно: Re:
Променен от Constellation36 (9. февруари 2009, 18:48:56)
spirit_66: Really understand your feeling.

There is hope my friend. I just had my first 66 in a bearoff situation after 11 games!! Now i'm moving from extremely unlucky area to just very unlucky one.

Suffices to say that my opponent had at the same game in the bearoff 33 then 44 and then 55.

6. февруари 2009, 21:57:13
Constellation36 
This site hates me!
In 4 games i was ahead and in some way ahead in pips from my opponent in bearoff situations or in a pure race in the Fevga game and my opponent won by having big doubles(66,55,44) multiple times!
They would not win having one or two good doubles but they needed more. No problem! They are having easily 3 good doubles while me having most of the time 41, 32, 51 etc. Perfect!

I guess it's just a pure unlucky statistical noise for me with just 10 games played so far, but to play a lot better, close the board perfectly and then lose by pure luck is way annoying.

Thank god this statistical short-range tendency happens for a short time but in the long run luck is balanced and skill prevails.

21. януари 2009, 12:03:54
Constellation36 
Hmm this is not rare. See the 4th move of white in this game also.

It seems it is just a display bug as players seemingly can't "hit" the blot and as one can see later in the game(6th move) when the white checker leaves that point the black checker is revealed again.

21. януари 2009, 11:44:08
Constellation36 
Относно: Plakoto BUG(serious).
In this game in the 10th move of black see what happens. The checker of white disappears!
And from the on white plays with 14 checkers!

14. януари 2009, 11:05:37
Constellation36 
Относно: Re:
nikos: >>These games (Plakoto & Fevga ) do know gammons and backgammons actually.
There are no Backgammons in Fevga and Plakoto. Only gammons.
Definitions are the same. In both Plakoto and Fevga if and only if you haven't borne off any checkers and the opponent wins the game, then the opponent wins a gammon, that is twice the value of the game, (that is 2 points in Greece as we don't usually use doubling cube).


>> In Greece at Plakoto for example,if the mother checker is pinned, this is a gammon.
As i'm trying to show wherever i play Plakoto, this is wrong and should not be used.
In the vast majority of cases it is true but there are some where it isn't.
I have shown why before some time with the example i gave below(or above depending on the board setup you have).

13. януари 2009, 13:00:16
Constellation36 
Относно: Re:
lukulus: And i wonder why these 2 games are played without cube?? I see no reason.
I guess it would be easy to implement in these games the doubling cube also.

4. януари 2009, 12:58:22
Constellation36 
Относно: Re:
coan.net: Too bad none of the tips could have helped me out in this game: Fevga (Albaowl vs. coan.net)

Oh my goodness!!!!!!!! That is the definition of "bad luck".

By calculating only your rolls(as calculating opponents rolls is a bit more tiresome and i'm lazy) the probability NOT to enter opponents board is:
0.047% or 1 out of 2115.

So the probability to enter opponents home(so you will be free to play later) is 99.95% or 2114 out of 2115.

And notice that the above do not take into account opponent's rolls, a thing that would actually increase your probabilities to enter.

So it's like you had a bag with 2114 white balls and only 1 red ball and you have chosen the red ball!
And note again that i have not taken into consideration the opponent's rolls that i guess would increase this probability to enter by a factor of 10(21139 out of 21140).

So many years i'm playing this game only once i have faced this situation and i was in the bright side, which means i forced my opponent not to be able to play at all.
And now i see it again.

Also notice what i've said a few lines before in this topic. In Greece we allow doubles in the starting roll for Fevga in contrast with what Brainking does. So there are 5 more cases(22,33,44,55,66) where one can advance high enough to enter opponents home or anyway to take the 12-point which is the key to avoid such position as then he will always have the change to so this can't happen.
So once again i will repeat that it is better if doubles will be allowed in the starting roll.

Of course what happened to you is extremely rare(writing a Monte Carlo based program to play millions of random rolls would easily show how exactly are the odds) and by allowing starting roll doubles becomes even more rare.

3. януари 2009, 18:43:14
Constellation36 
Относно: Re:
Fencer: No problem.

3. януари 2009, 18:09:23
Constellation36 
Относно: Re:
rod03801: I've seen one of your games and indeed, you played terribly. :-)

One notice about Fevga in Brainking. It would be a good idea to allow doubles in the opening roll of a player(i saw many games and never saw a double in the beginning) as this is how it's played in Greece. It makes the game more "unfair" but not by much and anyway i don't think it matters also.

3. януари 2009, 14:25:49
Constellation36 
Being a very experienced player of Fevga i took a moment to see a game.
It is the Rabbitoid - Alexlee.

I noticed some very very serious mistakes there. And i guess this happens for most Fevga games here. I guess this is definitely logical since it's a new game on Brainking and most players are inexperienced to Fevga.

Anyway i tried to analyze it a bit:
________________________________________________________________
1.pass 13-15, 15-20

2. 1-6, 6-8
2...20-24 In Greece our rules say that we are allowed to use the smaller roll of the dice only if we want too and only in the early opening phase(where you have to place a checker in the opponent's board) only, e.g we can play 20-21. I guess Brainking system implements Backgammon rules so you can only play the "4" of the roll and not only the "1".
BTW the notation of the board sucks big time. How can you call this 20-24 move while the Brainking's game's board says different things?

3. 8-9, 9-14 24-4, 13-16

4. 1-5, 1-3? A beginner's mistake. Fear about covering his board, but wrongly. How black can threat it? The nearest checkers is far away and even if it had 2-3 in close range again it will be wrong play. The correct play is to cover the !very! important 5 point of the opponent's board(the 18 point in the notation) and play 14-18! 1-3.
People don't realize how important is the 5 point in your opponent's home. The 18-point in the notation of Brainking.
It's probably the strongest point of the game generally. Another very strong point is the next one to the 18, the 19.
If you control these opponent struggles in most cases. So a player must try to control his 5 and 6 point before his opponent goes there.
And the other thing is that even good players at Fevga overestimate their home board and try to close it and make 5 -primes there(you are not allowed to make a full 6 prime there). We don't need this. This is wrong! Generally. We only need 3-4 blots there and it's OK. What we need is to advance. In the opening don't try to put as many checkers on your home board, but advance! Run your checkers to opponent's home and to the final home of yours.

Boards or areas are categorized into 4 areas of 6 points. 1-6 our home board, 7-12 the "prevention" board, 13-18 opponent's home, and 19-24 destination home.
The most important boards generally(with millions of exceptions unfortunately) are prevention board and opponent's board as also the first or second point(19 or 20) of destination board. But it depends on the opponent's distribution of checkers of course and his and our rolls.
But as a general rule: in the opening don't try to create too hard your home board but advance.

4...13-19, 13-17 Now this is debatable if it's the correct play. The other stronger alternative is 16-2 to press opponent's board while our board is perfectly safe(only 66 can threat it seriously). The played move, 13-9 13-17, covers the 6 point of black so it's a strong move. As i've mentioned previously the 19 point is very strong. In this case it's tough to say if with a 5 white would like to take it, but i think the answer is NO but it's not so easy to be sure.
Anyway to return to 16-2 or 13-9,13-17 debate perhaps both plays are equally good and they just represent different strategies.

5. 1-7, 1-5 ?? And this is a serious blunder. Very serious for 2 reasons: It doesn't cover the glorious 5 point of black(the 18 point). It allows black to create a !very! strong 4-prime if he gets a 5 next turn. And that kind of 4- prime for those who know the game is one of the strongest possible. So the strongest move is by far 1-7,14-18.

5...13-19, 13-19, 13-19, 13-19?? Very bad move. Does not understand the concept. Black !has! to bring another checker in opponent's home. Correct move by far is 13-19(2),16-22-4.
Now white even after his previous very bad moves, because of this time black lost with the big 66 and of course because of the wrong play, stands better.

6. 5-8, 1-2 Now this is very interesting position. The move played is very strong, to close everything in white's board. But it's not easy to say this. 14-18 i think would still be the best move here. The problem for black is he is behind on time so seemingly he can create a strong home and prevention board so black will get stuck behind it and eventually open first his primes.
But if you look closely the board, black is not so much behind on time and those 5 concentrated checkers on the 19- point give many plays. So if he gets his 5 home point and not get big doubles or 33, he is perfectly fine. Still worse(remember that the move played was very strong) but not by much. It's tough to decide between these 2 alternatives really.

6...19-22, 22-4 black gets a bit lucky here.

7. 1-6, 1-5? I just don't see why such unwillingness to play 14-18 here. Bad move again played here. White has to Just get the 5 point. It's his passage to the destination home.

7...13-17, 17-18

8. 5-8, 8-9

8...4-10, 13-18? Bad move. Black has to lose time and not bring another checker down from the "mana". He had to play 4-10, 19-24.

9. 7-12, 12-15?! Hmm giving the 7-point may be a bad decision. Black can take it and then white will not have an eays life with 6's and he will have to abandon another blot as he has no spare checkers. Also remember that black can safely take the 7-point and not be afraid of being primed at the home board of white, as white is not allowed to cover all 6 points of his board, so black can abandon the 4 point and to be like it has never did it(OK with 33 there is a difference but not crucial because of the 1/36). Also having a 2-3 distribution on opponent's home board does not put any real pressure on him. 1-6-9 is a better move.

9...13-19, 13-19, 13-19, 18-24 This is life. This is Backgammon, Fevga etc. Dice games generally. The opponent makes bad moves but he isn't punished for this. Actually he is in the long run, but in single games it's another story.
With these awful 66's white is now the clear favorite to win! Black is so much behind in time that he needs many small numbers(1,2) or white to get a 33 now.

10. 1-5, 5-7

10...13-19, 19-20!? Perhaps a dubious move, but maybe not. As i've said the blot on 4- point is almost useless as a blocking one(almost means 35/36 because a 33 is another story) and even if it wasn't there white isn't allowed to prime his home board. So black had to put pressure on white by bringing another probably permanent checker on his destination area by 4-10-11.

But maybe the move played is not bad after all, because of 2 reasons. First the 19-20 move is a very stong one and restricts heavily white's movement. And secondly if you observe white's board you will see no spare checkers so no flexibility at all. He has to leave blots to create new ones. With that in mind the original play may be the best after all.


11. 15-21, 1-3 A very important move is the 15-21. It gives a standing point where white can play. But it's nevertheless not so important now as white is the clear favorite anyway because of that awful 66 of black and because black was unwilling too to advance in the opening stages of game, his checkers to white's home.

11...19-22, 13-15

12. 1-5, 5-9, 9-13, 1-5?? A good roll that turns into an unfortunate roll because of a very bad play. Now soon enough after i declared white as the clear favorite, black enters dynamically into the game again and has some good hopes. A bad played 44 also. White should !!!!by all means!!!! have covered the 11 point as now with a 61 black takes it and also with a single 1 black should take it too to put more pressure to white. Also white should have left the spare checker on the 9 point and not play 9-13 as it is better to wait for a 5 and put that checker in the 14 point.
Correct play is 1-5-9, 3-7-11

12...19-24, 19-24, 18-23, 23-4 Oh God . 55's! This happens the worst time again. It's not a complete disaster for black as now although black is well behind in time and maybe get stuck and lose easily, he may also not get stuck and being so much ahead on pips will make him the favorite.
Probability is to get stuck, so he is the favorite to lose, but we will see.


13. 14-18, 21-23! Excellent move! Both moves make perfect sense.

13...24-4, 19-22

14. 18-21, 5-7?! This is a dubious move because of 5-7?. 18-21! was an excellent move as now the 18-point is much weaker than every point in the very important destination board. So white is correct to take every destination board that he is given. But 5-7? is bad as a 33 will mean a disaster for white. Instead of 5-7? a 1-3 would be more strong.
Remember Fevga(as like Backgammon and Plakoto and all Backgammon type games) are not about "Oh get real, is it possible to have a 33 now? That would be too unfortunate." Backgammon is about equity. And equity here must say that we HAVE to take into consideration and the 1/36 possibility of 33 so equity for 1-3 is bigger than that of 5-7.

But let's see it from another perspective. White is so much behind on pips. And if black manages to take the 11- point this will have a double super effect. White will suffer to take his checkers out quickly and effectivelly too, but also black will have deep board supporters for getting his checkers for bearing off. This is crucial and white should not let it happen. So perhaps instead of the move played, playing 6-11 is the best move. Black has not enough time and the checkers remained behind will have to move soon enough so white will get his checkers inside the destination.
One clear weakness 6-11 move creates is the obvious hole in the 6-point. But is it really so important? White will be able to bring his checkers out of home very easily. But the dagger in black's board the important 11-point will make black to stuck behind and waste many many rolls as he will not be able to enter his home board effectively as white would have 4 blots there. So eventually white will be able to enter easily(because of black not having enough time so he would move his checkers from white's destination area) to his destination area. It's a kind of duplication also as black needs 6 for playing on the 4-point and 6 also for playing into the 6-point.
And in stuck situations where one has stuck outside his board, the side that has stuck is losing badly.

So after all i think 6-11! was a truly great move and could have been played also. But playing 18-21,1-3! was very very strong too.



14...4-10, 10-11 Now white is in trouble. Had he covered that 11 point as i've said in a previous move this would not happen. By in trouble of course i mean that he has lost several points of equity but he is again the favorite to win but in a less extent than before.


15. 13-18, 1-5 19-22, 16-19, 19-22, 19-22

16. 5-8, 8-13 I'm not sure this is correct but it's highly technical and i'm lazy right now to count possibilities and cases. However it seems better to bring a checker from the "mana(1-point) by 1-5 for flexibility issues.

16...17-20, 15-17?! Dubious i guess. Again it's technical and i'm lazy to analyze it right now but 22-24 seems a move that had to be played. 2's are not easy to find so a spare checker there for a freeing 4 was better.


17. 3-6, 6-9, 9-12, 12-15

17...20-24, 24-4, 20-24, 24-4 And ta-daa, had black had another checker on 24-point and now black would not had to leave the 20-point. Not that it is too crucial right now but anyway.


18. 7-9, 13-14 4-10, 24-4

19. 14-16, 1-2

19...17-22, 10-12 Now the troubles of white by not covering that 11-point are seen clearly. Of course white still has the advantage but why to decrease your advantage, even by a bit?


20. 9-14, 18-20 19-24
21. 2-6, 14-18, 15-19, 16-20 11-12
22. 6-11, 18-21 pass

23. 1-3, 3-6?! I don't get this.Why to make life easier for black? Just sit there with 20-23,21-23 and wait. Anyway white is the big favorite to win either way. But now a 33 for black can make a difference. Why to allow that i don't understand.
Problem for white here is that black has plenty of 2's to play so he would not get that 16-point also. It will be a good battle but still white is the favorite.

23...22-4

24. 2-5,6-7?? 2-5 ????
Why to play 2-5? This is a serious blunder. Makes life of black much easier as it has many landing points and now black gets into the game very dynamically although white is still the favorite to win, but white lost even more equity.
6-9, 20-21 has to be the best play i guess.

27. декември 2008, 12:33:00
Constellation36 
Относно: Re:
Constellation36: In order to be clear about my:
like the tendency of "moves per day" (and yes this is an average obviously :-) ) when the number of games change, which is what you want.

"Moves per day" is an average as it is just a sample arithmetic mean(average) if we don't use all the active days the player has played games.

I guess your argument comes because actually when we speak about "moves per day" for a specific day and this is how you meant it i guess, that you mean "moves per 1 day" or moves that have been played in a specific day, so actually we divide by 1 so there is no actual average(mean).
And indeed if we speak about 1 day there is no real point for speaking about average, BUT mathematics are mathematics and definitions are definitions. :-) So "moves per day" for a specific, 1 day, it is an average(arithmetic mean). A trivial one.

It becomes non-trivial and worthful when we speak about "moves per day" over a period of time so if we have played 500 moves over 50 days we find the average 500/50 = 10 moves per day.

27. декември 2008, 11:40:32
Constellation36 
Относно: Re:
grenv: I disagree... the fact he has 200 games now is vitally important. In this case he will be twice as slow because he has twice as many games... This is meant to be something indicating *current* ability to play quickly.

Previously you proposed the indicator, let's say it S = (moves per day) / (number of games currently running) for measuring players speed ability to play games.
So what you say now about "the fact he has 200 games now is vitally important. In this case he will be twice as slow because he has twice as many games" does not make sense at all.

Reality is that if S is a good indicator, then it has to be kept almost steady, so if the player has double games to play than before, then the indicator S, estimates that the player will probably double his "moves per day" rate.

If you disagree that the S indicator can estimate that, then you don't actually need such an indicator as it's useless to predict anything, like the tendency of "moves per day"(and yes this is an average obviously :-) ) when the number of games change, which is what you want.

+++++++++++++++++++++++++++++++++

Also about your:
"What happened to the idea of rating people... moves per day / # of games currently running.

If this number was >1 you would expect a move per day, but a number of 0.1 would be a move every 10 days and you could avoid those players."


This is not true at all. That would be true if the indicator was "moves per day" and not "moves per day per number of running games".

+++++++++++++++++++++++++++++++++

The best indicator of someone's pace to play moves per day, is obviously the move per day indicator so what is best to do is to see::
A Y-X graph of Y = moves/day and X = days (for example for the last 365 days).
The standard deviation of the number of moves/ day, over the average moves/day for the last 365 days.
The arithmetic mean(average) value of moves per day, over the last 365 days for example.

The number 365 of days can be changed to the most desired, for example to be done for the last 6 months.

If the graph is "rough" with Everest types of maximums and many zero valleys and the standard deviation large, despite the value of the average moves/day, then the player is not very trustworthy to count that he will play quick.

The above 3 indicators, make the number of games a player has irrelevant, since a small standard deviation with a large average (that means a not "rough" graph), means the player's history says that this player plays fast, always fast, no matter the number of games.

Just my 0.02c.

27. декември 2008, 00:28:09
Constellation36 
Относно: Plakoto/Fevga Rules.
First of all i have to say a big WOW and kudos to Brainking that added Fevga and Plakoto to the available games. 2 of the most played Greek games along with Portes(which is a slight variation of Backgammon).

It's now time people from all over the world to learn and play the King of Backgammon-type of games which is Fevga of course!! Its deep strategic nature is incomparable with any known Backgammon-type game and i'm glad Fencer has chosen the Greek version(Fevga) and not its Turkish brother Moultezim nor the Russian Narde.
The last 2 are equally good games and slightly different than Fevga, but the more simplistic/symmetrical/logical/strong(that create a slightly more strategical game) rules of Fevga make it the best!

Fevga is very difficult to master and there are generally 4 main different types of main strategies one can follow to play it. All have their + and - and it's difficult right now to explain all on detail. For now i will just say that this game is by no means to create a 6 prime or a 5-prime, etc. It's not about big primes at all! It's about a combination of controlling the tempo(the definition of it is big and complicated), controlling the key squares of the position(that vary strongly depending on the position) not necessarily by big primes, having flexibility(MUCH more important than in Backgammon) and controlling the critical area of the phase of the game which is different each time and depends on the overall position, usually the critical area of the game changes 1 to 2 times in each game.

Plakoto is a very good game also, but i prefer Fevga and Backgammon as it tends to be slower than Backgammon and not so strategic as Fevga.

There are some different variations of Fevga described on the WEB that suggest how this game is played by Greeks and add to the confusion about it. I(a Greek indeed) have posted information on REC....Backgammon of how the majority of us play it and thank God the www.bkgm.com has listened to me and added my sayings into their rules.
Bad thing is that they have not followed my words exactly and now they have 1 mistake, but my emails for some reason, do not arrive to them.

The same mistake and one more serious(in Plakoto) is on the rules for both games here in Brainking.

The Brainking rules for Plakoto say:
--------------
Plakoto:
"The last checker on your starting point is called the mother checker. If this checker gets pinned by the opponent before it has left the start, the game is over and the player loses the game. The only exception is if the opponent still has checkers on his starting point, since in this case his own mother checker is still threatened. A game in which both mothers are pinned is a draw."
--------------

•This is not true as there is a very rare case(the fact it is very rare is irrelevant) where if one pins your mother and has escaped from the starting point, there is still hope for the player that his mother has been pinned to win.
►Look for example the starting position:
http://i215.photobucket.com/albums/cc34/Crocodile13/11662.jpg

►And how the game evolved(with Red to move):
http://i215.photobucket.com/albums/cc34/Crocodile13/1166.jpg

►Red has pinned blue's mother and red has moved all his pieces inside his home board. Red rolls 1-1 so has to release the pin on the blue mother as this is the only move. Blue now rolls 6-6 and we have a good battle now. :-)
Many other such type of positions exist.

+++++++++++++++++++++++++++++++++++++++++++++++++++++

The Brainking rules for Fevga say:
--------------
"It is allowed to build a prime (six consecutive blocked points) anywhere else (not in the player's starting quarter), but if opponent has collected all his checkers onto the one point behind player's prime, the player must unblock a point in his prime to allow the opponent a chance to move."
--------------

•There is a slight mistake on this.
The correct should be:
"It is allowed to build a 6-prime anywhere else (not in the player's starting quarter), but if the opponent for all possible dice rolls can't move any of his checkers (for example because he has collected all his checkers onto the one point behind player's prime), the player must unblock a point in his prime to allow the opponent a chance to move."

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