It seems like Iyama Yuta is losing his dominance of Japanese Go; he just lost the 6th game of the Kisei title match to Yamashita Keigo so it goes down to a deciding 7th game on the 19th/20th March. This comes after losing the Oza to Murakawa Daisuke and Tengen to Takao Shinji, and failing to capture the Judan. Maybe all that winning tired him out.

Interesting kill in this game, but black got a nice outside for a big moyo. Don't understand why he gave up on the lower left though, seems so big. Was his right group really going to die?

I would have thought he was losing it some but he did just come from beating Park Junghwan and Mi Yuting, so he can't be doing that badly overall. This just seems like a bad run against Yamashita here.

I was thinking that by the move 100 Iyama had it in the bag, considering his normal "a weak group destroys all opponent's territory". However, after fifty moves it was completely reversed in a mind-boggling middle game. I regained my respect on Yamashita. The seventh game will be good...

Cheers,
Vesa

So what happens if 128 connects? does p6 now kill due to those f4/g3 kikashi stones? That Iyama felt the need to hane under with e2 (f4 makes it too easy for black to make something in the corner?) makes me tihnk 118 could be a mistake, perhaps f5 is better though perhaps that leaves a little something at c4.

Maybe possible that the rest of the Japanese pro scene is catching up? Has Yamashita Keigo played in international competition recently?

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Tactics yes, Tact no...

Deciding game is live now on wbaduk (and others probably).

Iyama won to retain his Kisei title.

One thing to keep in mind. We are generally far to quick to attribute meaning to winning or losing streaks.

Imagine sixty four "players". In their last five games, a couple of the players won all of them and a couple of the players lost all of them. Should we comment on the couple of big winners, how they have improved? Or comment on the losers, how they are past it?

Now what happens when I tell you that each of the "players" was an honest coin that was flipped five times.

Except go performance isn't random in the sense of a coin flip. The point being made is that he was dominating the professional Japanese Go scene quite impressively, and has lost a bunch of titles. No-one's claiming he's becoming a rubbish player overnight, but I think it's fair to say that he's currently "not dominant" as he has been, and is therefore losing his dominance. He might get it back, if he's just having a rough patch, but that's a future issue.

One thing to keep in mind. We are generally far too quick to jump into threads and give preachy lessons of borderline relevance to the topic at hand.

Now what happens when I tell you that there is a flaw in your analogy?

That would probably depend on just what 'flaw' you put forward. I can't help notice that you did not do so. And just why is Mike's comment of 'borderline relevance' to a thread titled "Iyama Yuta losing it?"

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Dave Sigaty
"Short-lived are both the praiser and the praised, and rememberer and the remembered..."
- Marcus Aurelius; Meditations, VIII 21

In the analogy we don't know the player's strengths before the tournament, so we have no idea what is improbable, so we don't know what is remarkable. Treating something as remarkable in such a context is obviously weird.

In the real world, we do, so we do, so we do, so it's not.

Mike's post was totally on topic though, that is correct. Yours and mine aren't, but what can you do

I think it is likely that at the top level (Iyama, Lee Sedol, Gu Li, etc.) other factors than raw go strength determine who wins any particular game. That is assuming that raw go strength can be determined. But if these non-go effects are so important then we have to expect strings of wins and strings of losses and these have no connection with go strength. In any case I think many more games are needed to decide difference in strength, maybe 100 games or so.

When someone is dominating as hard as he did it's bound to happen that people will try to counter his style. It happened with Federer and it will happen with Djokovic (i remember at least a player to admit in an interview that he was practising especially for Fed) and with any other world class sportsman and the thing is he can't counter the whole field, some are bound to exploit some weaknesses . The other thing is that now that they're studying together these weaknesses become more apparent. He's also playing in a lot of matches, i was shocked when i saw him play Ke Jie the next day after he played Yamashita. I think it's a combination of all of those things: Japanese pros are starting to figure him out, he's playing a lot of matches, maybe he's trying to change his style and until he's reached a certain level he will have mixed success or maybe it's something else

I was not implying that go performance was random. In terms of the testing of theories, random is for the "null hypothesis" (that the effect being observed, in this case that a top player losing a string of games was random).

Look, if player A is a certain amount better than player B we expect A to win a higher precentage of games than player B. But each game is an independent event. In other words, if because of the difference in strength we expect player A to win 60% of the games against player B this does not mean that out of ten games played between them player A will win six of them and player B four of them. It means that in each of the games the probability of player A winning that game 0.6 and player B 0.4 The equivalent of a somewhat unfair coin being flipped.

But there is a probability that of the ten games, player B would win all ten of them, a probability of winning nine of them, of eight of them, etc. What I was saying is that people have a tendency to seek meaning when "just random" a perfectly acceptable alternative. That is what the coin example was all about. Somebody watching one of those coins come up five heads in a row too quick to decide "that must be an unfair coin". With enough coins being flipped, some of them will exhibit "runs" even though they are fair coins.

Look, this matter has been researched. For the ball player in a slump, no help at all. But analysis of the number and duration of slumps is actually around what would be expected if random. The same with "hot streaks".

There are enough top go professionals that some of them can be expected to win more or win less than evaluations of their strength indicate might be expected. It would tke a huge advantage over the other players (very high probabity of winnning each game) for us not to expect Iyama to lose some titles.

Analysing performances of go players in a match or matches is difficult using ordinary statistical or probabilistic techniques. In particular in a series of games between the same two players the individual games are not independent. I'm sure we all know two players who are equal in strength according to ratings but one, for some reason, wins most of the time. This does not mean that the ratings are not correct because ratings are based over many games with a large variety of opponents. Thus for any particular two players the ratings might not correspond to the actual chance of one winning. And, in a series of games between the same two players, there are strong psychological effects on the results.

Yes, all true, not disputing any of it, and also irrelevant. The point uberdude made was that "Iyama is losing it (his dominance) of Japanese Go". The number of simultaneous titles he held before compared to the number he holds now is indeed basically a proof of his point. He never claimed that "losing his titles" was unexpected, it was just a factual observation.

Seeing as I find Go more interesting than being retaught basic statistics I learnt years ago, here is the final game.



A feisty performance from both players with a lot of sharp tesujis and interesting shapes (e.g. move 32 wedging a one point jump shimari, just as in the recent European Pro qualifiers). And what would EdLee say about n9?!