* The point about levels of skill has been disputed here on the boards, but I still find it clearly true.

I see your point but yet im puzzled by what is exactly meant by depth?

I think finding grounds for comparison and the working out of such would be rather difficult given how different the games are.

It's actually not super-difficult. As I understand it, there are about 4000 points of difference in the EGF between a raw beginner and a 9d pro (-1000 to 2900), whereas in chess there are about 2500 points of difference between a raw beginner and Magnus Carlsen (300 to 2862). By the way, has anyone else noticed that Carlsen is the spitting image of Lee Changho?

Anyway, assuming Elo works the same way for the EGF and the chess world, that's a pretty solid grounds for comparison.

They're not the same, you're expected win rate against someone 100 points stronger than you in chess in FIDE's system is not the same as someone 100 points stronger than you under the EGF system for instance. You're expected to win more in the FIDE system (35% vs 29% approx).

And this is before you try and deal with the issue that normally all high dan games are even and all kyu games are not in EGF tournaments. So we've points ratings based solely on even games for the better players and handicap performance much of the time for weaker players. There are rather large issues with this from a prediction point of view, if A can give B 2 stones and B can give C 4 stones, must A be able to give 6 stones to C?

Well again, granting you that that's true, we're not talking super diff. Converting 4000 pts at 29% per cent into 35% wouldn't be too hard and I would do it right now except that I'm right smack in between cocktails and dinner.

Interesting to see HermanHiddema and Matthiasa mention the depth of go compared to other games as one of the elements that make it a better game. I see your point but yet im puzzled by what is exactly meant by depth? In principle these pure abstracts like checkers and reversi all have sufficient complexity to be as ´unsolvable´ as go to us (and you can always scale up the board size). Or do you perhaps by depth mean the amount of heuristics the game allows to evaluate a certain position on the board? (So that it is not ´depth´ in a tree-search sense) and that this is (to the human eye) richer in the game of go compared to many other games?

@matthiasa so you´ve tried Symmetry? cool!

Actually, 100 EGF is 20 kyu. AGA ranks go past 30 kyu. The systems aren't perfectly calibrated, but they're close enough that it's clear that there's a range of 20 kyus that the EGF lumps together in a single category of "players with rating 100".

An AGA 30 kyu is roughly an EGF -1000.

You can quibble about the exact numbers, but it does seem that Go has slightly more range.

Sure. Where I think it makes sense is that I don't think player strength is anywhere stable enough to talk about GoR ratings under 100, or even around 100 really. Talking about ranks under 20k is usually fairly pointless. I mean, if I grabbed an AGA 22k and a 25k would you be happy betting money on the 22k winning a 2 stone game? How about a 5 dan and a 2 dan?

Yeah, but the same is true of chess ratings under 1000.

Exactly. This is why I think it's pretty pointless to go Higher Bound - Lower Bound = Skill Gap.

Just because you can't identify a clear lower bound for either of them, doesn't mean you can't be fairly sure that there's a difference in overall bound difference or magnitude.

Not that this measure necessarily means very much, but I think chess and go probably really are quantifiably different under it, with go having a few more levels - I've thought about it before (with some of the same objections), and I think Go can be reasonably said to have at least a small number more of these statistical grading levels, though the original example (2900 -> -1000?) seems to make rather too much of the poorly defined beginner levels that may not fit well in the model.

I'll stress that I'm not saying that this makes Go harder than chess in any useful sense. Even if we wanted to apply it to real life, another vital number for judging difficulty levels is how quickly people tend to move between them. It doesn't matter how many of these levels statistically exist if Go players tend to move up them much more easily, for instance.

Edit: Oh, and another interesting observation is that chess ais have pushed the grading system up by (I think) a few hundred points! Depending on what you make of that, it would rather close the gap with Go, though of course we don't know how many stones go bots will be giving top professionals in 20 years