Iyama's world ranking

[Kirby]

Theory is a factor in game quality.

[hyperpape]

Theory is a factor in game quality.

The question wasn't "are old games better than current games in every way?", but whether more time makes for better play, using old games with longer time limits as one source of information. And longer time limits can make players better apply the theory they already have, and read better, and make better positional judgments, but it won't let them learn theory that took decades to develop.

[Kirby]

True, I see your point that we cannot absolutely answer the time limit question, even with an oracle. Your point about developed theory is one example among many.

Nonetheless, an objective measure of game quality is still something I look forward to, because it's much better than the hypothetical discussions we have now.

But anyway, yes, I agree that you still cannot definitively answer the time limit question, even if you can objectively measure game quality.

[hyperpape]

I didn't mean to imply it was impossible, though my first post could be read that way. There's a lot of this kind of work going on in chess, and I think it's providing value. It just also provokes interminable arguments about what it all means.

[Calvin Clark]

I'm not that optimistic about computers shedding light on move quality. It's not clear it would be better than modern pros commenting games of past players, it's just a different set of biases.

For any given move in a game, from computer analysis one can typically get:

1. A probability that black will win.
2. An expectation value for the score.
3. Candidate next moves.

Let's say that black is ahead (probability of winning > 0.5) and it's black's move. From one point of view black can play any move that does not result in being behind, and although humans might consider some of those moves too slack because they believe it should be safe to try for more, it's hard to say whether those are mistakes without looking at the position in more detail. I suppose if a move both lowers the probability of a win and worsens the score then it's likely a mistake.

If black is behind, it's even harder to say what a mistake is, for the same reason that it's hard to review the white side of handicap games. What's the best overplay? Or should one play as if the score is even and wait for the opponent to make a mistake? We have some evidence that computers often don't play in a way that's strategically effective against humans when behind. To do that, one might have to at least take into account a strength estimate of the opponent. It's not an easy problem for either humans or computers.

So for half the moves the game---i.e., the ones made the player who is currently behind, it may be very hard to come up with a metric for move quality. Any metric may have distortions that punish or reward highly tactical players, for example.

[Kirby]

Well, AlphaGo has trained a function for evaluating a position. Presumably it fares better than human judgment. It would seem to me that such a function could be used to evaluate a move.

CrazyStone already has this type of thing, which is useful in reviewing amateur games. Take that and crank it up to pro strength.

Not sure of the details, but maybe computers can help us gain insight in the future.

[idontgetit]

I definitely think it could be done, at least to a point that is superior and more precise to human professional judgement.

[pookpooi]

Iyama Yuta just won against Ke Jie.
According to non-goratings ranking, this would be called an upset due to Iyama's low rank.
But not in goratings, as they're both in top 10.

[ewan1971]

Iyama Yuta just won against Ke Jie.
According to non-goratings ranking, this would be called an upset due to Iyama's low rank.
But not in goratings, as they're both in top 10.

When did Ke Jie get out of the hospital? I'd been worried for him for a while because he was playing to exhaustion. Sure enough, he was hospitalized earlier this month.

[TheCannyOnion]

Iyama Yuta just won against Ke Jie.
According to non-goratings ranking, this would be called an upset due to Iyama's low rank.
But not in goratings, as they're both in top 10.

I'm surprised Iyama won. This is quite the achievement for Iyama, even if Ke Jie is in poor health and was just discharged from the hospital. I got the impression that Ke Jie at his full strength is almost a stone stronger than Iyama.

[kimidori]

I got the impression that Ke Jie at his full strength is almost a stone stronger than Iyama.

If we forget about Alpha Go, I think the difference between top players is nowhere near 1 stone. Top pros (even Ke Jie) cannot give top Chinese insei (would become ~ rank 300 worldwide when they become pros) anything more than 2 stones (even 2 stones would already be too hard). Iyama might be top 10 or top 30, but he is still top-pros level (mean he can beat anyone on a good day), so I would expect the difference (if any) to be no more than 2-3 points komi. Remember that if there is no komi, both players would play a completely different game.

[pookpooi]

Ke Jie beat Park Jungwhan, so his medical condition is probably more stable than what we worried that it might affect his match against Iyama Yuta

[ewan1971]

Ke Jie beat Park Jungwhan, so his medical condition is probably more stable than what we worried that it might affect his match against Iyama Yuta

Ke Jie does look healthy enough. However, according to Chinese news, he's still under the weather and suffering from the flu. From the video below, you can tell from his voice (toward the end where Ke Jie analyzed his own game) that he's still not 100%. That said, Ke Jie should have won against Iyama because Ke is much stronger.

https://www.youtube.com/watch?v=R2GOpe_OCzM&t=1649s

[pookpooi]

Ke Jie does look healthy enough. However, according to Chinese news, he's still under the weather and suffering from the flu. From the video below, you can tell from his voice (toward the end where Ke Jie analyzed his own game) that he's still not 100%. That said, Ke Jie should have won against Iyama because Ke is much stronger.

https://www.youtube.com/watch?v=R2GOpe_OCzM&t=1649s

Just like how Lee Sedol should had won against Ichiriki Ryo back in September 2016. My interprete is that Japan is not that far behind as everyone's believe.
Or are you suggest that Park Jungwhan (or South Korean pro as a whole) rank is overestimated cause he lost to the ill-condition Ke Jie?

[idontgetit]

I have been quit skeptical of goratings' ratings, and to some extent, I still am. Meng Tailing, for example, should be ranked higher than Byun Sangil. And guys like Lee Yeongkyu are way too high despite not doing much.

Still, if I really look at Iyama's games and results, I think he is definitely strong. I wouldn't be surprised if he can reach semis or even finals of international tournaments if he actually participated in them.