A problem I had with scoring this game

Hello, I can confirm that you counted correctly. The estimator uses area scoring (Chinese rules), which is more computer friendly but can produce a conflicting result in close games that use a territory scoring ruleset. Sorry for the confusion.

2 Likes

The difference comes from
1 point for black played the last move and
1 point for black filling 1 dame after white passed.

1 Like

Aren’t they the same?

Only if

  • white played the last move,
  • no player passed and
  • there are no eyes in Seki.

Im not sure if handicap stones are compensated in Chinese rules.

1 Like

I think they get either half or full point compensation, but yes that is taken into account.

To expand on the most notable differences:
In Japanese rules:

  • Only empty surrounded space (territory) counts for a point each
  • Every prisoner (and opponent’s dead stone that remained in your territory) gets you a point

In Chinese rules

  • Both the surrounded spaces as well as the stones surrounding them count for a point each
  • There are no extra points for prisoners
  • Generally they give an extra point for a komi

A pretty good comparison of different rulesets is here:
http://www.britgo.org/rules/compare.html

Generally both the rulesets usually yield the same result (so don’t bother with it unless you really want to know), but under special cases or by some unreasonable moves (like filling your own territory) they can start to differ - as discussed above

1 Like

Thanks, that clarifies a lot.
I still don’t understand why black playing the last move should matter, though.

In area scoring the stones count as points. if white passes and black gets to play an extra stone then they get an extra point. when it goes black/white/black/white the points stay even but black/white/black white misses out on the equalising move.

2 Likes

Just to be clear, in the Japanese ruleset it doesn’t matter.

Correct, but in Japanese filling in your own territory DOES matter, whereas it doesn’t in Chinese.

1 Like

See also:

3 Likes

There are two kinds of problems with the estimator:

  1. Hard to estimate scenarios (seki, oddly placed stones etc)

  2. Japanese vs Chinese differences at the end of the game.

The first one is a “Hard Problem”. No-one expects a solution in the short term.

This thread is really about the second one, isn’t it.

anoek recently commented that he thinks that we can do better about the second one, and has it on his list to tackle that, so that we don’t get this “wait, the estimator told me a result that is 1 stone different to the real result, at the end of the game”.

3 Likes

The estimator tends to give points in places that clearly are and will be dames, i think this is exactly due chinese counting, where living stone in dame actually do count as a point. But when you are using japanese rules, there won’t be any points by playing dame, nor connecting fake eyes or such.

In your game white did pass twice, after pass on move 278 black played j4, which would have been +1 point move with chinese rules, but not under japanese ones.

2 Likes

while all the discussion about about difference between chinese rule and jap rule is correct, i think they are not the cause of OP’s question.

and estimator works reasonably well when you are down to the last stone or something.

i THINK the problem is that, in the final score, 3 areas were NOT COUNTED. why did that happened i don’t know

1 Like

Fair point. Brings us back to the golden rule. When playing against bots:
image
EXTERMINATE enemy pieces before scoring.

Nb. Chinese Rules allows this to be done without changing the score. :stuck_out_tongue_closed_eyes:

1 Like

The game was counted correctly.
This is just a visual problem after you have used the SE. If you reload the game you can see that the game was scored correctly.

4 Likes

The official Chinese rules make no mention of handicaps. So how handicaps are handled is on a per server basis or player agreement. Anything you read on the subject would merely be someone else’s interpretation of how they believe it works or how they personally house rule it.

According to this article at the BGA, Chinese rules count the total number of stones (for example, 4) and divide that number by two (4÷2=2). That total is subtracted from Black’s final score and added to White’s final score. Black gives White compensation for handicap stones, so that the area which they occupy is not counted.

Concerning how OGS handles the scoring for Chinese Handicap, compensation is awarded to the opponent. The number of Handicap stones is added to the opposing player’s score. This can easily be seen in this game, when hovering the mouse cursor over the number of captures for Budgie.

The numbers there usually don’t sum op to the player’s score. The handicap 4 would be there even under Japanese rules.
Under AGA rules the handicap 4 would be 3 points for white if I recall correctly.

Are you saying that the number of handicap stones aren’t added to the opponents score? Here is a completed game that shows that they are being applied.

As far as I understand, in OGS:

  1. “The final score of the game”, outside of estimator, is correct, there is not bug around it luckily, and you can pretty much trust the final result as being right (assuming that dead stones and such are correctly marked by players at the end of the game).
  2. The score estimator is just an estimate, and has always been fairly unreliable. I recommend that you try getting used to never using it, as it feels more like playing on a real go board, but that is just a matter of preference. It is important to understand though, that estimator is just an estimate, and can be and often is wrong.
  3. The estimator always uses Chinese Rules, no matter the actual rules used in the game (Computer-simulation techniques are generally easier to implement in chinese-like rules). This can be a further source of confusion.
  4. The estimator has (had? I think it was not fixed, but I might be wrong) an important easy to fix bug for handicap games, because it does not correctly take into account the handicap stones in chinese score (it is customary to subtract N-1 points to black’s score in handicap games when counting chinese, because black starts with “one additional point per extra stone” in the beginning, so subtracting them makes the “amount of handicap” equivalent both when playing chinese or japanese). That means that, in an N stone handicap game, it is off by about N points, even at the very end of the game. We discovered that during a game in the Argentine online league. A more detailed explanation is here Score estimator is very wrong in handicap games, and also very easy to fix
4 Likes