World Go Championship 2019

[xiayun]

Round 1:

Cho U vs. Shin Jinseo
Liao Yuanhe vs. Park Junghwan
Ke Jie vs. Yoo Changhyuk
Jiang Weijie vs. Iyama Yuta

[Uberdude]

Shin and Ke won as expected. Iyama won too against Jiang who currently rated a fair bit above him so that's nice for Japan. Park won too.

Tomorrow:
Ke vs Iyama
Shin vs Park

First variation Iyama is black, 2nd Park is black.

[Ember]

I really enjoyed the English language commentary on the Nihon-Kiin's Youtube channel by Antti Törmänen today a lot and I'm looking forward to seeing more of that tomorrow - and hopefully another win for Iyama! I wonder if it'll be similarly spectacular as the Kisei game last week..

[Uberdude]

Ke and Park won, so play the final tomorrow. They'd better practice nigiri!

[jonsa]

Kind of disappointing for Iyama. It seemed like he was in the lead until he double hane'd instead of cutting. I was sort of expecting a breakthrough for him.

[Uberdude]

The theme of both games seemed to be that it's hard to kill groups.

Iyama is white vs Ke:


Park is white vs Shin:

[John Fairbairn]

The theme of both games seemed to be that it's hard to kill groups.

The Japanese commentary on Game 7 of the Kisei made the point that Iyama deliberately made 3 weak groups. Given the orthodoxy that deliberately making one weak group is accepted as a valid shinogi strategy but making two is stupid, what are we to make of three? Is this perhaps part of the pro response to trying to learn rom the bots?

It may also signal a change in style by Iyama as he strives to close the gap with his international rivals.

[Control]

Regarding the game between Iyama and Ke, Ke's S13 then Iyama's answer look somewhat questionable to me. Wouldn't it better for Iyama to look for a move that takes care of center or bottom or maybe both?

[sorin]

The theme of both games seemed to be that it's hard to kill groups.

Iyama didn't have to kill anything to win.

Cho Chikun was very optimistic about Iyama's chances, so was LZ: Iyama dominated Ke Jie the whole game pretty much.

He had trouble bringing the win home because he had too many ways to win while in time trouble, if I understood some of Cho's comments correctly. Well, Cho may have missed some variations since he seemed very busy trying to entertain the audience with all sorts of jokes

Anyway, one thing I personally learned after this game, I hope, is to never think again that I have a won game and it's over until it's over-over.

[Uberdude]

@John, I think this take the money and say "Ner ner ner ner ner, you can't make enough profit attacking me" style could be influenced by bots being very good at it, but it's not as if humans never thought of it before. So not so easy to say definitely AI influenced, unlike easily recognisable new opening ideas.

@Control, keeping s13 dead is very big, not just for points but also for safety of the right group and giving m9 group somewhere safe to run. Would you suggest something like m7 instead? I think black would s12, get the r10 peep and then s14 and say whatever white does on lower side he can't close any big efficient territory so black can still mess it up, and on th right there are future attacks and middle stone aji still useful with eg n8/n10 peep.

It looks like Iyama's 164 instead at p10 would be a safer win, maybe he was too much looking forward to l16/m12 pokey pokey fun fun once he took that lib?

Anyway, one thing I personally learned after this game, I hope, is to never think again that I have a won game and it's over until it's over-over.

I have learnt this too many times

[Control]

@Control, keeping s13 dead is very big, not just for points but also for safety of the right group and giving m9 group somewhere safe to run. Would you suggest something like m7 instead? I think black would s12, get the r10 peep and then s14 and say whatever white does on lower side he can't close any big efficient territory so black can still mess it up, and on th right there are future attacks and middle stone aji still useful with eg n8/n10 peep.

@Uberdude, I liked your m7 variation for white but do not completely share the concern of white's exposition to an (far fetched) attack on the right, wouldn't it be ineffective for black? Actually, following black's s14 in that variation I would even consider playing p3 to (possibly) induce him for another move at the right (s6 maybe) even then white's r12 group seems to be quite in safe and black doesn't get much territory.

[Uberdude]

Poor Ke Jie, made another stupid late endgame blunder (n11 timesuji* was gote) in a final vs Park so lost by 1.5. Park wins his 3rd World Go Championship in a row.
* Actually it does defend against black L11 so not as inexplicable as it appeared.
P.S. Why was f3 necessary at that time? I can see some shortage of liberties troubles if white connects in response to the m6 atari but that's just a 5ish point gote so couldn't white do a11 sente endgame first? On the stream Ke Jie was obviously getting flustered, not placing stones at the correct point (n11 was played at o11 right at end of overtime period and he moved it to n11, maybe letting go of it first, naughty!) whereas Park remained calm.

[sorin]

P.S. Why was f3 necessary at that time? I can see some shortage of liberties troubles if white connects in response to the m6 atari but that's just a 5ish point gote so couldn't white do a11 sente endgame first?

I was wondering the same - I found a possible answer in the Japanese commentary on WBaduk, sorry for just posting it as a screenshot.

[sorin]

Poor Ke Jie, made another stupid late endgame blunder (n11 timesuji* was gote) in a final vs Park so lost by 1.5. Park wins his 3rd World Go Championship in a row.
* Actually it does defend against black L11 so not as inexplicable as it appeared.

I don't think it was "timesuji", as in thinking it's forcing - it is a big move. I think he just miscalculated the size of the other move Park played, maybe realizing too late that F4 is sente.

Here is the moment he played O11-turned-N11: https://youtu.be/QI6QEAdNbOM?t=21998

If you keep watching a couple more minutes, he slapped himself several times (with breaks in between).

Later, technically, he even takes a move back, but then replayed in the same place: https://youtu.be/QI6QEAdNbOM?t=22824

[Uberdude]

sorin, nice, I didn't see the 1st line atari of 8, just the peep on 2nd line. My idea was white could play a11 for sente profit before coming back to f3 if it is indeed necessary. Trouble is W f14 / B g14 is so big and tedomari. I played out the endgame with both white f3 and allowing black g14, and white taking f14 so sacrificing the m5 stones and white still lost, but only by half a point instead of 1.5. Heres an sgf with variations (don't pay too much attention to the LZ percentages in the file as they assume 7.5 komi). Go to variation on move 250.

P.S. If white captured at f4 instead of n11 then even if he allows L11 to connect instead of fighting the ko I get a half point win for white.