But isn't it quite common (not that it necessarily tells you anything meaningful)? It sounds just like a test question in a statistics class.
For the round of 32 --> You have an urn with 10 red balls and 22 white balls. In randomly drawing 16 pairs of balls from the urn without replacement, what is the probability that you will not draw any pairs of red balls?
For the round of 16 --> You have an urn with 9 red balls and 7 white balls. In randomly drawing 8 pairs of balls from the urn without replacement, what is the probability that you will not draw any pairs of white balls?

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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

Sure, you can calculate a probability. But interpreting this as support for the hypothesis "pairing mixes countries" which was only made after the event is dodgy.

Obligatory xkcd: http://xkcd.com/882

You're making a general point about statistical inference, Uberdude, but I wonder how much weight it holds in this case. The reason is roughly that while it's true that Joaz looked at the data and saw a potential correlation, rather than thinking of a question then looking at the data, there's also a limited set of patterns he might have noticed. After all, while it's true that there's some chance that players whose last names begin with A-G are paired with players whose last names are paired with H-Z, or some other silly pattern, it's unlikely that anyone will comment on that pattern if it appears. If there are a thousand patterns you might notice, then you do have to be highly sceptical if any appears. If there are two, then you only need to be slightly sceptical (where sceptical is a placeholder for various statistical corrections you might use).

I think there are really only three patterns that are highly likely to be commented upon: pairing strong/weak players against each other, pairing players of different nationalities against each other.

Anyway, we really should just hunt down information on pairing, and/or look at the previous years to get more data.

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Occupy Babel!

We can just wait for the round of eight. As we all know:

Mr Bond, they have a saying in Chicago: "Once is happenstance. Twice is coincidence. The third time it's enemy action." -- Auric Goldfinger

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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

so, what's the update pairing for the next rounds?
can anybody make the tournament's tree?

Well, since the same thing happened in the first round (15 non-Chinese players were paired in EVERY CASE with a Chinese player), I think Joaz must be right. The same analysis in the first round gives the probability of 17/31 * 16/29 * ... * 4/5 = 16384/17678835 or about 0.000927, or 0.09 percent. Very unlikely!

Also, it would be easy to do this in practice: just give one group of fans numbered 1 to 16 to the non-Chinese (plus one Chinese, who was actually fortunate since he didn't have to face a Korean player), and another group numbered 1 to 16 to the Chinese.

i usually keep myself from struggling for more attention than i deserve, but if you check my post #34, it already brought some of the facts and guesses repeated on this page.

also, i've found NO unnecessary in-country pairings in ANY round of the 3 previous seasons of the LG cup (looked one year further back when writing this post). it virtually proves that pairings are made as to avoid match-ups from the same nationality. still it wouldn't be pointless to read the actual rules, to learn of possible other criterion and if the starting numbers play any role in pairing after round 1

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Spilling gasoline feels good.

I might be wrong, but probably not.

Ah, sorry, you're quite right. Missed your post.

So what?

Would you like to qualify by a really tough preliminary for a world championship just to play the guys from your local go club even though it could be avoided? Only rule nuts without common sense can believe this would be a more desirable procedure.

Tapir, I don't see anyone complaining. We're just curious and willing to engage any silly abstract topic that drifts our way.

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Occupy Babel!

Seriously OT: You meet a lot of people who are against such common sense things as not pairing people from the same place in amateur tournaments because it doesn't combine well with their favourite tie breaker. Every time SOS performs badly they blame the pairing. Remembering this I was carried away...

Yes, I was making a more general point, as this abuse of probability/statistics is very common (e.g. http://www.bbc.co.uk/news/uk-politics-18102529) and I want to make the world a better place by stopping it .

I do agree that this case is weaker than others due to the relative scarcity of "interesting" patterns. But I can already add to your 3: pairing of players of the same nationality is surely just as interesting. And there could be interesting events involving subsets of the group, e.g. pairing people with the same surname or repeating draws of recent tournaments.

P.S. looking at past draws, I agree it looks very likely they do pair to mix countries, which I think it a good idea.

It is lunch hour.


Lee Changho stepped away from his game and watching Lee Sedol's game.










Seo Bongsoo anounces starting game.



Images from Oro.

trout, thanks for the oro photos. The venue looks very nice: the floor, walls, ceiling, lighting -- all look very nice, grand, and classy...
except for the ugly tablecloths.
The brown ones are not so bad, but the green ones...
In fact, if the tables are halfway decent, simply removing the green tablecloths would be a plus.

For such a nice international tourney with a budget, you'd think they can do better than the green tablecloths.
They remind me of CGoban's ugly green background.

Result of round of 16,
Lee Younggu defeated Xiao Zhenghao by resign.
Shi Yue defeated Lee Sedol by resign.
Na Hyun defeated Jiang Weijie by resign.
Li Kang defeated Lee Changho by resign.
Won Seongjin defeated Choi Kihoon by 5.5.
Lian Xiao defeted Park Junghwan by 1.5.
Kang Dongyoon defeated Peng Liyao by 0.5.
Choi Cheolhan defeated Gu Li by 0.5.


Many prominent(highlighted) players were lost in this round.

Next round will be played in November(11/05) according to igokisen.

I love these updates from Trout!

Lee Sedol lost - the plot thickens...

omg. my friend surely stress a lot for this one. he's the fans of Gu Li. It'll let him fire up in the tourney in the weekend. T_T

Pairing for round of 8,

Na Hyun vs Shi Yue
Kang Dongyoon vs Li Kang
Choi Cheolhan vs Lian Xiao
Won Seongjin vs Lee Younggu

Korea
China


Image from Oro.

Round of 8 - 11/5/12
Semi final - 11/7/12

It will take 5 months to find all of them??

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Help make L19 more organized. Make an index: https://lifein19x19.com/viewtopic.php?f=14&t=5207

omg. why does it have to be that long? anybody know the reasons?