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KGS and its rank

Written by alejo on May 28th, 2007

We all know KGS, you may like it, you may dislike it. But we must all agree in how crazy his rating is.

Last September, KGS decided to modify its internal rating. Now, it is supposed to be more difficult to reach high levels while the lower levels are narrower; so lots of players concentrate at the 15k-1k zone. Everyone was affected by this change and players’ rating grew about 5 stones by this procedure. Everyone was affected in the same way, so all your opponents also increased by 5 stones their level.

It is well-known that internet ratings are slightly higher than the real ones: as you can see KGS’ ratings are always a few stones higher than AGA’s or European’s on the lowest levels which should be restored somewhere later to have a good equivalence on the higher ratings.

Where is that?

It’s on the 9k. As you can see, a 9k KGS player varies up to 4 stones on each real scale.

 AGA   CHINA  EUROPE   JAPAN   KOREA  |  IGS  DGS  KGS ---   -----  ------   -----   -----  |  ---  ---  ---   26K    30K     28K     25K    32Gup  |  BC 25K    29K     27K     24K    31Gup  |  BC 24K    28K     26K     23K    30Gup  |  BC 23K    27K     25K     22K    29Gup  |  BC   25K 22K    26K     24K     21K    28Gup  |  BC   24K 21K    25K     23K     20K    27Gup  |  22K  23K   15K 20K    24K     22K     19K    26Gup  |  22K  22K   15K 19K    23K     21K     18K    25Gup  |  21K  21K   14K 18K    22K     20K     17K    24Gup  |  21K  20K   13K 17K    21K     19K     16K    23Gup  |  20K  19K   13K 16K    20K     18K     15K    22Gup  |  20K  18K   12K 15K    19K     17K     14K    21Gup  |  19K  17K   12K 14K    18K     16K     13K    20Gup  |  18K  16K   11K 13K    17K     15K     12K    19Gup  |  17K  15K   11K 12K    16K     14K     11K    18Gup  |  16K  14K   10K 12K    15K     14K     11K    18Gup  |  15K  14K   10K 11K    14K     13K     10K    17Gup  |  14K  13K    9K 10K    13K     12K      9K    16Gup  |  13K  12K    9K  9K    12K     11K      8K    15Gup  |  12K  11K    9K  8K    11K     10K      7K    14Gup  |  10K  10K    9K  7K    10K      9K      6K    13Gup  |  9K    9K    8K  6K     9K      8K      5K    12Gup  |  8K    8K    7K  5K     8K      7K      4K    11Gup  |  7K    7K    6K  4K     7K      6K      3K    10Gup  |  6K    6K    5K  3K     6K      5K      2K     9Gup  |  5K    5K    4K  2K     5K      4K      1K     8Gup  |  4K    4K    3K  1K     4K      3K     *1D     7Gup  |  3K    3K    2K *1D     3K      2K      2D     6Gup  |  2K    2K    1K  2D     2K      1K      3D     5Gup  |  1K    1K   *1D  3D     1K     *1D      4D     4Gup  | *1D   *1D    2D  4D    *1D      2D    4-5D     3Gup  |  2D    2D    3D  5D     2D      3D    5-6D     2Gup  |  3D    3D    4D  6D     3D      4D    6-7D     1Gup  |  4D    4D    5D  7D             5D                   |              6D  8D             6D                   |              7D  9D             7D                   |              8D 10D                                  |              9D

This table is extracted from Sensei’s Library: World Wide Comparison.

So, if KGS has to recovers this 4 stones at the 9k level… why didn’t they leave the old system? Sincerely, I don’t know the answer. I don’t mean that KGS2 rating is better than KGS3, but it may have been more "real".

Talking about "better"… I think that none of the KGS rating systems are good. For example: how can you improve your level at KGS? By NOT playing.

In fact, my original account at KGS "alejo" showed this image today:

Which is something obviously wrong. I haven’t played with this name for a couple of months and there are only 3 games listed for the last 6 months… As you can see, inactivity is the best way to increase your rating.

The real fact is that I’m at 9k. Yes, 9k at KGS, which means that I don’t know where I’m at all.

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Related posts:

  1. “What’s your rank” poll results
  2. Founding a club with complete beginners
  3. Alejo returns to KGS
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9 Comments to “KGS and its rank”

1. Posted by pel, May 28th, 2007 at 3:58 pm

First off, I don’t really see the need to have some sort of ranking system that works the same everywhere. In fact – I think that this would be impossible. Isn’t it enough that rank guides us towards finding an interesting game with a suitable oponent?

Looking, for instance, at the EGR (European Go Rating) system there is ample evidence that this system suffers from geographical variance; I’ve heard rumors about similar circumstances in AGA. It is possible that there might exist such discrepancys on KGS too. E.g. people only playing certain hours of the day, mostly playing people in certain rooms. But this is only speculation. The point is that these disturbances occur and they are not easy to manage.

That said.. KGS ranking system certainly is weird. Some players around my level are unbeliveably weak/strong. This seems very strange to me.

2. Posted by nik, May 28th, 2007 at 4:29 pm

There is no such thing as an absolute rank, it’s all relative within one ranking system. For example in Korea, there used to be no amateur dan ranks and a 1 gup (=1 kyu) was the strongest rank an amateur could get. The only real measure of a Go ranking system, in my opinion, is whether the differences in ranks are an accurate prediction of the proper handicap needed for a good game. For this purpose, the KGS3 ranks are much much better than the KGS2 ranks were. In fact, around my level (KGS3 1k) many people stopped playing handicap games altogether with KGS2 because white was at such a disadvantage.

Your criticism of how ranks tend to solidify when you play a lot and become crazy is valid. I don’t see the problem of getting weird ranks when you stop playing however – after all, you are not playing, so why care about that rank? (it even gets marked with a questionmark for everyone to see that that rank may be wildly inaccurate) – but for players who play a lot it can take a long time of winning the vast majority of games to move up sometimes.

3. Posted by Alejo, May 28th, 2007 at 5:33 pm

Of course there isn’t an absolute rank (though it’ll be nice) and we just play for fun. But it is logical to think that an European 10k will beat a 13k without handicap… while both are a 9k on KGS.

I understand the problem with KGS2 and handicapped games… hadn’t thought of it… but, anyway, isn’t there a better way to fix this problem at the 9k level? For example, following an average between the other ranks, the “weakest 9k” should be around 12k; just increasing one stone per level… as usual, as all the other ratings do.

And I’m sorry, but I don’t accept that my rating increases even if I don’t play, it should be somewhat stable. I understand the method they use for calculating your rating based on others’, but this leads to such incredible situations:
I beat someone who is 15k… then I’m, at least, 14k… Next game I lose against a 13k, then I’m 14k… Two months later, the 15k player has reached 3k level and this affects me in a way that I become somewhat like 7k.

I still dislike those two problems of KGS ratings…

(Anyway, I’m going to modify the size of the “commentary writing”, they are too small…)

4. Posted by Alejo, May 28th, 2007 at 5:39 pm

Weird… very weird indeed… X-files… hehehe…

“Isn’t it enough that rank guides us towards finding an interesting game with a suitable oponent?”

Yes, should be, but you also recognise that you find people who are incredibly strong or weak at your same level, which is something that the rating system should avoid.

Now, I will appear as a weak 2d player. Toooooo weak, indeed.

This is one of the consecuences of this bug of KGS… what should I do? Losing against bots till I reach something near 9k? Lose against a 1k player who will start thinking that he has beaten a 2d, affect his rating and so on?

5. Posted by Alejo, May 28th, 2007 at 6:08 pm

Well, finally solved the problem of the comment’s size.

6. Posted by Nate, June 18th, 2007 at 1:09 pm

I like the new KGS3 ranking system, as it seems quite close to real life AGA rankings.

I think the problems that made you a 2 dan could have happened on KGS2 system.

7. Posted by Alejo, June 18th, 2007 at 1:15 pm

Yes, I agree that this could have happened on KGS2. In fact, it already happened to me at the very beginning… but I expected it to be solved on the new ranking system, partialy, at least.

Maybe I was expecting too much…hehe

8. Posted by Codexus, June 18th, 2007 at 7:55 pm

There is no such thing as KGS2 and KGS3 ratings. It’s a myth. There had been similar adjustments before and there are going to be others when needed. There had been a slow drift towards the bottom of the scale and the adjustment that occurred at the same time KGS3 was released just restored the previous ranks. It’s been almost a year why are people still bothered by that?

As for the validity of KGS ranking algorithm it’s very good but only if you play a lot, if you don’t play enough the system has not enough data and in the kyu ranks that creates some overrated players.

9. Posted by Alejo, June 19th, 2007 at 8:33 am

The own KGS server calls it KGS3… Maybe it’s just an adjustment (I don’t really know), but in order to identify this “new” period the go comunity calls it KGS3.

It’s been a long time since they modified it, I know. But the point is not arguing about KGS2 and KGS3, the real endpoint of this post was to criticise how KGS algorithm deals with players who don’t play much.

And, in fact, if there had been a “slow drift towards the bottom of the scale” I think it could have been better… Currently KGS3 overrates players compared to all other real-world ratings on the lower levels.

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