Life In 19x19

Cho was doing well for much of the 2nd day, but that all changed around move 123, see my Elf commentary.



Edit: I spoke too soon! Iyama just played an endgame blunder (-50%), a peep that wasn't sente enough when he owed a defensive move, and now Cho has a picnic ko to eat some stones and has a thicker position so more ko threats. That's a silly way to lose a Meijin title match.

At move 210, white is about 3 points ahead with only small yose left. It looks like we are getting a new Meijin.

Indeed, Cho won by 4.5 to become Meijin again, 10 years after he last won it (also beating Iyama 4-3 in 2008). What a surprising comeback, and Cho's first big title since his dominance of the pre-Iyama era 2003-2012. It's the player who makes the last mistake who loses the game...

The full game; 171 was the losing move, defend at p7/8 would win. I wonder was it an oversight, a failed timesuji to get time to decide on the best defence, an attempt to kikashi before defending?

Cho U's 40th title, and his 5th Meijin title. Quite amazingly, he won 4 of his 5 Meijin titles 4-3 in best-of-seven matches.

Just counting the big 7 titles, it's Cho U's 24th. Iyama remains on 4I so still just behind all-time leader Cho Chikun on 42 (Kobayashi Koichi has 35, Kato Masao 31, Rin Kaiho 21, Sakata Eio 22 though those last 2 were playing before all 7 existed). The generation before Iyama are doing as good a job as after at taking titles off him recently: Cho in 2018 Meijin, Takao in 2016 Meijin, whilst youngster Kyo Kagen in 2018 Gosei. (older) Yamashita is 1-1 in Tengen this year and (younger) Ichirki Ryo 1-0 in Oza (after losing 10 in a row in title matches last year).

Uberdude wrote:Edit: I spoke too soon! Iyama just played an endgame blunder (-50%), a peep that wasn't sente enough when he owed a defensive move, and now Cho has a picnic ko to eat some stones and has a thicker position so more ko threats. That's a silly way to lose a Meijin title match.

I can imagine Fujisawa "The King of Blunders" Shuko reading this, and shaking his head: "Youngsters nowadays... in my time we had really silly ways to lose a title!"

2nd Oza game is live now. Can Iyama put his recent bad results behind him and get back to business as usual of beating up Ichiriki like his 10 wins in a row in the last set of title matches?

Update: Iyama won by resign. I didn't review with LZ yet, but it seemed to me he was always on the front foot from the top left fighting onwards.

Iyama won the 3rd Oza game too fairly convincingly once the big fighting started.

Uberdude wrote:Iyama won the 3rd Oza game too fairly convincingly once the big fighting started.

With a seven-stone-long stick on the second line, no less!

WindCaliber wrote:

Uberdude wrote:Iyama won the 3rd Oza game too fairly convincingly once the big fighting started.

With a seven-stone-long stick on the second line, no less!

Reminiscent of AlphaGo vs Park Junghwan. Interestingly LeelaZero said Ichiriki shouldn't have extended the last time as that allowed black to live in sente (getting the turn in sente as followup is a nice bonus but not worth enough for gote) but played first in the centre, even though he would then have to endure Iyama playing hane up which hurts the liberties of the white wall plus being big for territory. But getting the first move in the balance of power fighting in the centre was more important, and is the kind of think I think bots are very good at judging.

And Iyama won the 3rd Tengen game vs Yamashita to take a 2-1 lead there too.

Uberdude wrote:And Iyama won the 3rd Tengen game vs Yamashita to take a 2-1 lead there too.

Why did Yamashita resign? It wasn't at all clear to me that black was doing badly.

Black considered that his M17 group is dead?

That black m17 group would be locally dead had been clear for a while, when he resigned it was clear that all the surrounding white groups were alive and therefore m17 wasn't going to live from winning a semeai on one of them.

Ichiriki beat Iyama in the 4th Oza game by 1.5, in the middlegame FineArt said he had 100% win chance so I think he probably slacked off a bit (why not fight ko at top right?). Deciding 5th game is on 13th December.