My son is about 13k on IGS but seems much stronger than 9k on KGS
I play about 2k on IGS and 2k on KGS seems easy.

KGS 5d says IGS 5d was easy.

So, I believe there is a crossover point somewhere. Does anyone know what that is? 1-2d?

Seems correct. I am 12-13k on IGS and 7k on KGS. In this area the rank difference between IGS and KGS is quite large.

KGS ranking system is little messed up. I have 4k in EGF, around 1k on IGS and Tygem and 2d on KGS. There is at least 4 stones of inflation on KGS in kyu and low Dan area.

It seems ideal way to start is to play with bots on KGS and start playing until you get to about 10-12k and move over to igs with ranking of 16k. IGS BC and 17k should be avoided.

I play as 5k EGF and 4-5k KGS. While my sample size of EGF games is low I didn't have the impression that there is such a big gap. And I'm more trained in quick online games than slow offline games.

I'd rather guess that it's EGF that's messed up, having large regional differences, since I can't imagine winning offline against someone how can give me 5 stones online.

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Sanity is for the weak.

I also think so. There's quite huge regional difference, but it's still hard to believe a KGS 2D is only EGF 4k.

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求而不得
舍而不能

I played a handi game witha 10k on KGS. He told me that his rating went up just watching the lectures. WTF??

So, I was not too surprised when I tested another 12k on KGS. I waited for him to simply hane to get rid of my second eye (really basic shape cut and dry) and it never came. So, though of killing has never entered his mind.

I have observed this, and I think that prevalent playing styles may play some role in the difference. This is just anecdotal, but in the SDK range, the players on IGS seem to play a bit more aggressive (or a "berserk" style), also seems typical for many Japanese KGS players. Some people may more successfully counter this style than others.

Just a thought. I could be totally off base.

EDIT: I should also note that I use IGS as my "drunk account" or "I don't feel like reading" account.

Is there any way estimate a "true" rating, or is IGS assumed to the the most accurate?

What do you mean? Ratings are independent. There is no "true" rating. If you say "my ranking is 5 kyu" to 10 different people, they could have 10 different perceptions of your playing strength. So there is no "1 dan" or "10 kyu" independent of a rating system. There is KGS 1 dan, which may or may not differ from IGS 1 dan, etc.

Accuracy is a different issue and depends on the data. The ranking methods used by IGS, KGS, the AGA, EGF, etc., are all reasonably accurate depending on how many rated games an individual has played (and how recently, etc.), which isn't to say any of them are perfect. So if you've played a bunch of games on IGS, but not on KGS (or games rated by the EGF or AGA, etc.), then IGS is probably the most useful for you. The only real way to determine your KGS rating is to play rated games on KGS (same for Tygem, AGA, etc.).

Actually.. I think I read somewhere that dan ranks were supposed to correspond to the number of stones you would need from (the weakest) professional player, meaning 1dan needed 9 stones.
If we enforce that rule, some rating systems are more accurate than others.

that's not really true. originally there was no such thing as amateur dan ranks. only professional dan rank.

that's why in the Korean book "First Kyu", he's just one step away from becoming a 1-dan professional at "amateur" 1 kyu.

I'm around 11 kyu on IGS, and "berserker style" is in understatement. If you can fend off the endless overplays, you win the game. If you get sucked into the knife fight and misread, you lose.

On the bright side, it is entertaining. Try Tygem, it is like IGS on speed.

My experience is completely different. On IGS at 17-10k, my opponents play very calmly, solidly and it's a very nice go to look at. On the other hand, every single player on KGS plays overplays and moves that doesn't make any sense and it is very ugly go and no fun at all. Even at 17k, which is the lowest on IGS, the players know how to play a nice game. On KGS, look at 15k playing, it makes me wanna kill myself.

I haven't played that much on IGS,

But, I'm at 4d KGS right now (which is taken to be unusual by some given how most AGA 6d are 5d on there. And my record as a 6d AGA is pretty good)

I've played a number of EGF 4d-5d and Chinese 4d-5d, and based on the results, (as well as their estimation) I'm Chinese 4d, EGF 4-5d (though technically, in the EGF database, I'm like 2580, but that's an artifact of insufficient data)

So... I think the evidence for KGS 2d = EGF 4k is pretty slim... but there are huge regional variations in the EU. (It's not even worth trying to use ranks to gauge the handicap with a Finn, just play even and see what happens)

On average though, there is not a 6 rank difference between any of the rating systems, and if you are experiencing it... it's probably just you.


The other thing to consider is the "style" of servers. Certain servers can be beat by a particular style. (The secret to ORObaduk seems to be to play a solid opening and then beat them up with their overplays)

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Tactics yes, Tact no...

I have found this to comparison on sensei's library to be fairly accurate.

http://senseis.xmp.net/?RankWorldwideComparison