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 Post subject: Breadcrumbs on the board
Post #1 Posted: Thu May 23, 2019 3:10 am 
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Hello everyone. I finally decided to have a small journal for my notes.
I'm about 3d in strength on Fox and 2k on OGS. My main server is Fox.

I intend to share some interesting positions here or some snippets of shapes that I've learned.
All commentaries and questions are welcome.

お願いします


This post by jouseki was liked by: Bill Spight
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 Post subject: Damezumari
Post #2 Posted: Thu May 23, 2019 4:57 am 
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In the recent game I've had a very interesting position, on which both me and my opponent spent 30 minutes total time reading things out.
I was black.

It started this way:



I've made a huge mistake of not pushing through white's stones in order to create the cutting points. I knew of this tesuji, but I blundered.



At this point, I was looking at playing either A or B. We can examine A first:



I have read about this far (it's one way street, so it's not that difficult) and figured out that I probably will not be able to win the semeai against neither A nor B nor C. So I quickly discarded this option.
As for B:



I couldn't find neither A or B working for me, so the atari variation is no longer possible in this branch.

After I discarded both of these atari variations, I've started reading out some better tactical moves. The first instinct was to play the bamboo joint. This way I don't get 1 move behind by playing atari and connecting up.



There was an obvious shape problem for white's corner, so after this cut I thought I had the best chances to figure something out.
The game went this way:



At this point, my opponent has 3 candidate moves.
I figured, that if they choose A or B, I can extend at C and I will definitely be able to capture the cutting stones.
Let's look at this variation.



If white A, then black B and atari.
If white C, then black D and atari.
If white D, then black C, white can try getting out with two atari, but black eventually wins, because the liberty B will be empty.

However, my opponent has found the solution to that which I have completely missed in my reading. They have spent about 8 minutes reading this out.
The game went this way:



Now, my move at A wouldn't work, because my cutting stones are short on liberties. White can attach at B as a response and then get out with the bamboo joint regardless of what black does.

At this point, I thought that I have collapsed. I've spend 10 minutes reading out all of the possible variations, and there's a lot to consider.

First, there's this semeai. It's almost 1 way street until it comes to ko. In the game, I've read to move 14 and figured that I will probably not be able to win it. But in the post analysis I found out that black can indeed with in this position.



Next, there's this small semeai, but black doesn't have a good response to the cut. However, I still had to keep in mind that any defense I play to this cut will affect this semeai. Although I would probably need a bit more than just a defense to the cut.



And finally, there's these cutting stones. My first instinct was to play the jump, but following this sequence I was afraid that I wouldn't be able to prevent white from connecting. I've read about this far and discarded this variation, but after the game I realized, that it would be the same if not better than what happened in the game.



Eventually, I have settled for this position. At first, I couldn't find the refutation to this hane, but I was mainly reading out the cross cut at B. However, shortly after playing the move, I discovered the counter hane from white, that is A.
At this point I was convinced that I completely screwed it up.



As for the cross cut, my reading was as follows.
I've tried to make the following move work, but I couldn't find a way to defend both A and B here, so I quickly discarded this move.



Next, I found this ko. But for some reason, I decided that it would be too risky to play it. At the time I was convinced that I could settle the position without a ko.



And finally, I found this move. From here I was convinced that the crosscut wouldn't work for white.



In the game, white have found this counter hane move, which I have not read out at all.
My first instinct was to play the following variation. But at the end, it was clear that it would be impossible to contain white's stones for me.
In the post analysis I found out that Leela is ok with this variation, she just begins the corner semeai shortly as she's convinced that black can win it (and I have discarded this possibility earlier).



After about 5 minutes of reading, I was approaching byo-yomi. The following diagram is the farthest I could read, so it was my only hope.
At the very end, before deciding to play it out, I've tried to imagine how the semeai would go.
I noticed, that I have 2 inside liberties that white can't fill because they need to connect at A and B. However, I was pretty short on time, so I couldn't count the liberties properly.

This is also how the game went (accordingly to my reading):



White started the semeai and the game went as follows.



My opponent missed the fact that I have 2 extra liberties due to his weakness in shape, so white resigned here.
Had I not have those extra liberties, white would've won the semeai by 1 liberty exactly. I commend white for being able to read it out as well.

I had a lot of fun reading it. It was a roller coaster for me, but at the end I was about 70% sure that I would win the semeai, even with the extra liberties. Maybe I just got tired from reading everything out.


This post by jouseki was liked by 2 people: apetresc, Bill Spight
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 Post subject: Re: Breadcrumbs on the board
Post #3 Posted: Thu May 23, 2019 8:04 am 
Judan

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Gosh, what a lot of reading! I rarely read that much, and I eat Fox 3ds for breakfast. So I think if you put even a fraction of that effort into all your moves, you'd easily win without getting into such dicey positions. In AI terms, maybe you need to improve your policy network more than your playouts depth. You already mentioned the not pushing through at h17 mistake, but also just before that if you played f18 at g18 then your 2 groups would be trivially connected so no scope for troubles like the game (f18 does hurt the top left corner more though so greed is nice if you can get away with it). Also in one variation at the end you said B doesn't work here.

jouseki wrote:

I couldn't find neither A or B working for me, so the atari variation is no longer possible in this branch.

It does, squeeze for ladder :)

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 Post subject: Re: Breadcrumbs on the board
Post #4 Posted: Thu May 23, 2019 8:53 am 
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Uberdude wrote:
Gosh, what a lot of reading! I rarely read that much, and I eat Fox 3ds for breakfast. So I think if you put even a fraction of that effort into all your moves, you'd easily win without getting into such dicey positions. In AI terms, maybe you need to improve your policy network more than your playouts depth.


That's true. Reading is what I enjoy the most about the game, but sometimes I miss very obvious moves that should require 0 reading from me, and it leads to an eventual collapse.
At Fox 3d my regular game is where I lead by over 20 points, this is the buffer I need to make up for the blunder that I will eventually make. In my estimations, 20-25 points lead will become a -2.5 to +2.5 point game, something in that range.
But it is what it is. The only downside to it for me personally is that I never get to play "an even opponent" so to speak, but since my win/lose record keeps me at 3d, it probably means that I am 3d, so I don't really have an argument here.

Uberdude wrote:
You already mentioned the not pushing through at h17 mistake, but also just before that if you played f18 at g18 then your 2 groups would be trivially connected so no scope for troubles like the game (f18 does hurt the top left corner more though so greed is nice if you can get away with it).


I don't remember exactly why I decided not to play the clamp. I also know of that tesuji, but I think I imagined that white would push up and connect somehow. Unfortunately I didn't give it a second thought and just played the sagari.

Uberdude wrote:
Also in one variation at the end you said B doesn't work here.
jouseki wrote:
I couldn't find neither A or B working for me, so the atari variation is no longer possible in this branch.

It does, squeeze for ladder :)


Totally missed that one, thanks for the hint.

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