The 73rd Honinbo is upon us!

Uberdude · Post by **Uberdude** » Sun Jun 03, 2018 6:38 am

Shenoute wrote: 143, leaving the left side as is in order to not even kill the corner (since white can still live with Q1 even after 143)

My guess is his plan/hope/dream is that white would live in gote with q1 m5 s2, and the point is by encouraging white to make the q1-m5 exchange black is now able to save the n9 cutting stones (there was a damezumari before) and thus the k6 push and cut aji become significant and he hoped to use that in the left/centre fighting. However, Iyama showed fighting spirit and didn't comply, saying the left was more urgent and kept fighting there. I'm inclined to agree with him. (Also maybe it was a timesuji but probably they weren't in overtime yet).

Shenoute wrote:- 155, did black dislike so much not having two eyes locally after something like e6- d6- b6- b3 (while on the other hand d6 at least gave him an unconditionally living group on the side)? If so, the cost seems pretty high, with the center stones not having eyes and white stones being much stronger because of the f5 cut.

Rather than b3 at the end there I think white would pull out the cutting stone at g7 (now that g6 is atari), forcing black to live at b3 and could then return to live at q1 (or play something on top if you think that's bigger) now that the k6 cut is pretty much taken care of. That would be a moral failure for black so instead he chose to live in sente on the left and keep fighting in the centre to make good on his k6 threat, but his shape was rather sucky and Iyama kept on fighting with that cool double peep.

Shenoute · Post by **Shenoute** » Sun Jun 03, 2018 7:15 am

Uberdude wrote:Rather than b3 at the end there I think white would pull out the cutting stone at g7 (now that g6 is atari), forcing black to live at b3 and could then return to live at q1 (or play something on top if you think that's bigger) now that the k6 cut is pretty much taken care of. That would be a moral failure for black so instead he chose to live in sente on the left and keep fighting in the centre to make good on his k6 threat, but his shape was rather sucky and Iyama kept on fighting with that cool double peep.

Yes, I agree that white would probably go first in the center rather than play b3. Even then, as black, I'd prefer getting rid of the center once and for all instead of dragging the g9-h8 stones but maybe that was too big...

harumi · Post by **harumi** » Mon Jun 04, 2018 6:10 pm

Thank you for doing such a thorough summary and extra's!

Uberdude · Post by **Uberdude** » Tue Jun 12, 2018 3:32 am

Another Honinbo title match game with bot-inspired opening, after first day (black just played kosumi and white connected, I'm expecting b9 and then e9 and all sorts of squeezy fun):

Click Here To Show Diagram Code: [go]$$Bc Iyama (black) vs Yamashita $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . . . . . . . . . . . | $$ | . . . , O . . . . , . . . . . X . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . O O . . . . . . . . . . . . . . . | $$ | . . X X O . . . . . . . . . . . . . . | $$ | . X . O X X . . . . . . . . . X . . . | $$ | . . O W O X . X X . . O . . . . . . . | $$ | . O . O X X . O . . . . . X O . O . . | $$ | . . O O O X . . X X . O . X . , . . . | $$ | X O X X X O O O O O . . O . . X . . . | $$ | . X . . . X X . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

Shenoute · Post by **Shenoute** » Tue Jun 12, 2018 4:56 am

Oops, forgot to post! Thanks, Uberdude.

Game 4 (first day)

Video coverage: https://www.youtube.com/watch?v=Qyb0zmrJSuU

I dislike white's position as much as I dislike black's, so...equal game I guess?

Tryss · Post by **Tryss** » Tue Jun 12, 2018 5:41 am

For what it's worth, at this moment, LZ prefer white (giving W a little over 70% winrate).

Shenoute · Post by **Shenoute** » Tue Jun 12, 2018 6:08 am

Tryss wrote:For what it's worth, at this moment, LZ prefer white (giving W a little over 70% winrate).

Oh, that sounds like a lot. Could it mean that black doesn't have much to gain from the shenanigans on the left side?

Uberdude · Post by **Uberdude** » Tue Jun 12, 2018 7:05 am

Iirc Yamashita was quite a bit ahead in the early opening in their last game according to LeelaZero/Elf (surrounding the 4-4 point not enough compensation for Iyama when Yamashita got the g3 turn in sente; interestingly very similar to a game of mine I posted in my study journal recently, based on the bot idea that press to 3-4 is bigger than answering 4-4 double approach, though at least Iyama played b4 not b3 like my opp) but ballsed it up soon enough.

I checked a few bits with LeelaElf:
- it doesn't like (-4%) Iyama's 3-3 but prefers traditional f3, maybe because of o4 trying to develop lower side? (If I turn lower right to just the 3-4 then 3-3 not so bad but still prefers f3, or #1 shimari lower right, AG teaching tool shows 3-3 as best but gives no information on approach or shimari). If we believe that judgement, it seems even top pros might be copying the AIs a bit too much without understanding them

- wants to j4 peep for 25. I've seen bots (Golaxy, LZ?) do this a lot. Or d8.
- really doesn't like 33 e5, g6 instead, w spends move on left and b gets ahead in lower side fight.
- I suppose W left is too good and the peep too late (because now W doesn't mind sacrificing 3 stones as black made a load of bad exchanges on the left side), it likes Yamashita's m4 which I thought cool.
- It didn't see the kosumi but descend. W d6 connect big mistake (but I'm using <1k playouts so don't trust so much in positions like this that need reading, Elf gives W 76% before, 66% after), I suppose he didn't want Iyama to get b4 or some other relatively minor but easy gain in sente, connect means no easy pickings for Iyama but potentially big fruits in complicated outside stuff as a lot more play in the position now.

Uberdude · Post by **Uberdude** » Wed Jun 13, 2018 4:01 am

Iyama won by resign. Yamashita actually kept his lead (according to Elf, too hard for me to judge) for longer than I expected, but as usual Iyama kept the game complicated with unsetttled groups fighting and Yamashita made 2 big mistakes: 134 (should capture in middle) and 144 (should play at B's 145, if B kills right group then W kills lower middle one); I wonder when he went into overtime. I liked the way Iyama made Yamashita's life in the lower right have a negative effect on the big outside group so avoiding an endgame.

Another interesting little shape lesson: Iyama played 1 below. After some play in top left and right white slid at a, so although 1 was solid it didn't make much territory. Elf preferred to play 1 as kosumi at b or knights move at c (which one changed a bit based on surroundings: before Iyama's squeeze on left it liked c more). If black can get both these moves it's more efficient and I suppose the corollary is that black doesn't fear white running at p6 after kosumi because too busy. In fact the marked white approach and black high answer were the moves just before white's slide, Elf says black should play the kosumi now to close the territory (or k10), double approaches against a 4-4 are nothing to fear, kosumi has real profit, and the high move just makes the slide perfect. This kind of kosumi attempting to gobble up more efficiently is something I've noticed with bot reviews a few times (it's not really part of my shape repertoire, and although I expect pros consider it more than me I suspect still not enough).

Click Here To Show Diagram Code: [go]$$Bc Iyama (black) vs Yamashita $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . . . . . W . . . . . | $$ | . . . , O . . . . , . . . . . X . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . B . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . O . , X . . . . , . . . . . , . . . | $$ | O . O O X . X . . . . . . . . . . . . | $$ | . O . . O O O X . . . . . . . . b . . | $$ | . X O O X X X . . . . . c . . X . a . | $$ | . . O O O X . X X . . O . . 1 . . . . | $$ | . O . O X X . O . . . . . X O . O . . | $$ | . . O O O X . . X X O O . X . , . . . | $$ | X O X X X O O O O O . . O X . X . . . | $$ | . X . . . X X . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

Shenoute · Post by **Shenoute** » Wed Jun 13, 2018 4:37 am

Game 4

Yes, Uberdude. I was a bit surprised by some of the plays on the side, starting with 128. I would have thought that playing in the center and putting pressure on black here would have been more interesting.

Uberdude · Post by **Uberdude** » Wed Jun 13, 2018 4:56 am

For 128 r8 has the obvious problem at s6 (though would black do it now or just be happy to have created the option for a big corner later), but what's wrong with r7? I'm guessing Iyama had some plan to do with sacrificing and getting a squeeze with p8 and some more stones in the area would enable him to kill the upper right white group? Or q9 looks interesting. I'd be happy as black to play r8, but maybe that's just because I don't see black's dastardly plans if white played there first

.

Uberdude · Post by **Uberdude** » Wed Jun 13, 2018 1:37 pm

Caveats apply, but here's Elf's winrate graph at 2k-4k playouts.

: Iyama-Yamashita g4 winrate.PNG (442.71 KiB) Viewed 8087 times

EdLee · Post by **EdLee** » Wed Jun 13, 2018 5:25 pm

Hi Tryss,

For

, does LZ/Elf have any opinion about the game move, v. the clamp B16, or other options ?

Uberdude · Post by **Uberdude** » Thu Jun 14, 2018 12:53 am

Hi Ed (I guess you mixed up which of me and Tryss were using Lizzie in which thread!),
I suppose you are wondering about the clamp because you thought it was quite nice for black to get c17 and c18 to live nicely and giving white the broken shape making b18 silly? That was also my feeling watching the game. On the other hand white got a ponnuki, so f14 ended up silly, but that one's harder to judge. Here's a simple variation we can compare against, Elf gives white 66% after this, it was 72% before. In this position b18 for c17 is obviously a terrible exchange for white, but also black hasn't made bad exchanges giving white a ponnuki so white's outside is much less thick (e.g. nice peep shape point at a).

Click Here To Show Diagram Code: [go]$$Wcm76 $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . 2 . . . . . . . . . . . . . . . . | $$ | . X . O . . . . . . . . . . . . . . . | $$ | . . . , O . . . . , . . . . . X . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . X O . a . . . . . . . . . . . . . | $$ | . . . 1 . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . O . , X . . O . , . . . . . , . . . | $$ | O . O O X . X O . . . . . . . . . . . | $$ | . O . . O O O X X . . . . . . . . . . | $$ | . X O O X X X . . . . . . . . X . . . | $$ | . . O O O X . X X . . O . . X . . . . | $$ | . O . O X X . O . . . . . X O . O . . | $$ | . . O O O X . . X X O O . X . , . . . | $$ | X O X X X O O O O O . . O X . X . . . | $$ | . X . . . X X . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

Elf likes the b18 attach, but likes the k10 influence point 1% more, I think it is generally good at this kind of whole-board vision. After b18 it agrees d13 hane is best and then initially counter-hane of game but after ~50k playouts prefers "heavy" e14 pull back. It does think about clamp a little bit:

: Yama clamp.PNG (188.55 KiB) Viewed 8010 times

Expected continuation, note after clamp you need another move or black can extend due to 79 support, 81 haengma is elegant, white ends at 68% with the slide, clearly the best place to spend the sente says Elf:

Click Here To Show Diagram Code: [go]$$Wcm78 $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . O . . . . . . . . . . . . . . . . . | $$ | . X 3 O . . . . . . . . . . . . . . . | $$ | . 1 . , O . . . . , . . . . . X . . . | $$ | . . X 2 . . . . . . . . . . . . . . . | $$ | . . X O . . 4 . . . . . . . . . . . . | $$ | . . . X . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . O . , X . . O . , . . . . . , . . . | $$ | O . O O X . X O . . . . . . . . . . . | $$ | . O . . O O O X X . . . . . . . . . . | $$ | . X O O X X X . . . . . . . . X . 5 . | $$ | . . O O O X . X X . . O . . X . . . . | $$ | . O . O X X . O . . . . . X O . O . . | $$ | . . O O O X . . X X O O . X . , . . . | $$ | X O X X X O O O O O . . O X . X . . . | $$ | . X . . . X X . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

With the game line Elf thinks white should have extended for 80 (2% better) and black just captured from Atari. So black c18 was a little -1%, and white's capture best (if block then big -15% mistake as black will extend not capture and live in sente (e12 needed or f16 cut), getting to play the k10 or r8 key point (it flips between them). White is down to 52% here. With the game line white would be 72% if he played s8 slide, but the o17 approach took that down to 65%, but then Iyama's answer an even bigger mistake (k10, with f8 atari first, or r8 preferred) and back up to 78%!

Click Here To Show Diagram Code: [go]$$Wcm82 $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . O 1 . . . . . . . . . . . . . . . . | $$ | . X X O . . . . . . . . . . . . . . . | $$ | . . . , O . . . . , . . . . . X . . . | $$ | . . X 4 2 3 . . . . . . . . . . . . . | $$ | . . X . X O . . . . . . . . . . . . . | $$ | . . . X O . . . . . . . . . . . . . . | $$ | . . . . 5 . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . O . , X . . O . , . . . . . , . . . | $$ | O . O O X . X O . . . . . . . . . . . | $$ | . O . . O O O X X . . . . . . . 6 . . | $$ | . X O O X X X . . . . . . . . X . . . | $$ | . . O O O X . X X . . O . . X . . . . | $$ | . O . O X X . O . . . . . X O . O . . | $$ | . . O O O X . . X X O O . X . , . . . | $$ | X O X X X O O O O O . . O X . X . . . | $$ | . X . . . X X . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

EdLee · Post by **EdLee** » Thu Jun 14, 2018 4:06 am

Hi Uberdude, thanks.
I still don't have any bots, so I'm at the mercy of others who do.
Just whoever has the time & energy to run these nice bots.

Life In 19x19

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