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 Post subject: Re: Knotwilg's practice
Post #181 Posted: Wed May 27, 2020 6:59 am 
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So what would have been a better move for 107, and how to use the aji of the cut stones?

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 Post subject: Re: Knotwilg's practice
Post #182 Posted: Wed May 27, 2020 8:22 am 
Gosei
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Rank: KGS 2d OGS 1d Fox 4d
KGS: Artevelde
OGS: Knotwilg
Online playing schedule: UTC 18:00 - 22:00
Click Here To Show Diagram Code
[go]$$ Position at move 106
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . O X . . . |
$$ | . . . . . X . . X . O . . . O X . . . |
$$ | . . X , . . . . . , . . . . . X . . . |
$$ | . . . X . . . . . . O . . O . . . . . |
$$ | . . X O . O . . . . . . . . . . X . . |
$$ | . . X O . O X . . . . . . . . . . . . |
$$ | . . X O X O . . . . . . . . . . . . . |
$$ | . . X X O . . . . . . . . . . O O . . |
$$ | . O . X O . X . . , . . . B . X X O . |
$$ | . . . O . . . . . . . O . . . . . O . |
$$ | . . . O . O . X . . . . O . . X X O . |
$$ | . . 1 . . . W . X O O O X . . X O . . |
$$ | . . . . . . . 2 X O X X X . O X O . . |
$$ | . . . X . X X X O X X . . O . X X O . |
$$ | . . X , . . O O O X O X X X X X O O . |
$$ | . . X O . . . . . O O O O O O O X X . |
$$ | . . O . O . . . . . . . . . . X . X . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ ---------------------------------------[/go]


The situation is not easy. After BB jumped, WW peeped and then I (Black) played B1.
Katago thinks this is a 14% mistake. Instead, KataGo thinks about 2 other moves.
Before discussing them, let's look at the situation

Click Here To Show Diagram Code
[go]$$ Position at move 106
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . O X . . . |
$$ | . . . . . X . . X . O . . . O X . . . |
$$ | . . X , . . . . . , . . . . . X . . . |
$$ | . . . X . . . . . . O . . O . . . . . |
$$ | . . X O . O . . . . . . . . . . X . . |
$$ | . . X O . O X . . . . . . . . . . . . |
$$ | . . X O X O . . . . . . . . . . . . . |
$$ | . . X X O . . . . . . . . . . O O . . |
$$ | . O . X O . X . . , . . . X . X X O . |
$$ | . . . O . . . . c . . O . . . . . O . |
$$ | . . . O . O . X . . . . O . . X X O . |
$$ | . . . . . . O . X O O O X . . X O . . |
$$ | . . b . . . . a X O X X X . O X O . . |
$$ | . . . X . X X X O X X . . O . X X O . |
$$ | . . X , . . O O O X O X X X X X O O . |
$$ | . . X O . . . . . O O O O O O O X X . |
$$ | . . O . O . . . . . . . . . . X . X . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ ---------------------------------------[/go]


The big question is if Black has the time (eyespace) to connect at ''a''. Not only can White cut off a couple of stones and build a centre, also White's central stones are currently disconnected and White ''a'' would help a lot.

A blunt connection at ''a'' would make Black very heavy. White can poke at Black's shape with moves like ''b'' or ''c'' (AI favorite).


Click Here To Show Diagram Code
[go]$$ Position at move 106
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . O X . . . |
$$ | . . . . . X . . X . O . . . O X . . . |
$$ | . . X , . . . . . , . . . . . X . . . |
$$ | . . . X . . . . . . O . . O . . . . . |
$$ | . . X O . O . . . . . . . . . . X . . |
$$ | . . X O . O X . . . . . . . . . . . . |
$$ | . . X O X O . . . . . . . . . . . . . |
$$ | . . X X O . . . . . . . . . . O O . . |
$$ | . O . X O . X . . , . . . X . X X O . |
$$ | . . . O . . . . . . . O . . . . . O . |
$$ | . 3 . O . O 1 X . . . . O . . X X O . |
$$ | . . 4 . . 2 O . X O O O X . . X O . . |
$$ | . . . . . . . . X O X X X . O X O . . |
$$ | . . . X . X X X O X X . . O . X X O . |
$$ | . . X 5 . . O O O X O X X X X X O O . |
$$ | . . X O a . . . . O O O O O O O X X . |
$$ | . . O . O . . . . . . . . . . X . X . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ ---------------------------------------[/go]


Katago suggests a better shape move to guard the connection: :b1:. Then instead of connecting, it suggests another shape point: :b3:. After :b5:, there's an exchange with White taking the center and Black playing ''a'' and capturing. Very high level stuff.

So what's this about? What if White cuts?


Click Here To Show Diagram Code
[go]$$ Position at move 106
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . O X . . . |
$$ | . . . . . X . . X . O . . . O X . . . |
$$ | . . X , . . . . . , . . . . . X . . . |
$$ | . . . X . . . . . . O . . O . . . . . |
$$ | . . X O . O . . . . . . . . . . X . . |
$$ | . . X O . O X . . . . . . . . . . . . |
$$ | . . X O X O . . . . . . . . . . . . . |
$$ | . . X X O . . 7 . . . . . . . O O . . |
$$ | . O . X O . X . . , . . . X . X X O . |
$$ | . . . O . . . . . . . O . . . . . O . |
$$ | . 3 . O . O 1 X . . . . O . . X X O . |
$$ | . a 8 . . 2 O 5 X O O O X . . X O . . |
$$ | . . . . . . 6 4 X O X X X . O X O . . |
$$ | . . . X . X X X O X X . . O . X X O . |
$$ | . . X b . . O O O X O X X X X X O O . |
$$ | . . X O . . . . . O O O O O O O X X . |
$$ | . . O . O . . . . . . . . . . X . X . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ ---------------------------------------[/go]

With Black having better shape at :b1: and White worse at :b3: the mutual cut becomes a problem for both. White's left is not as thick as in other variations and his center is in dire straits.

When :w8: presses, Black will be able to connect underneath, provided ''b'' is sente. That's where this move comes from.

Click Here To Show Diagram Code
[go]$$ Position at move 106
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . O X . . . |
$$ | . . . . . X . . X . O . . . O X . . . |
$$ | . . X , . . . . . , . . . . . X . . . |
$$ | . . . X . . . . . . O . . O . . . . . |
$$ | . . X O . O . . . . . . . . . . X . . |
$$ | . . X O . O X . . . . . . . . . . . . |
$$ | . . X O X O . . . . 8 7 . . . . . . . |
$$ | . . X X O . . . . . 6 5 . . . O O . . |
$$ | . O . X O . X . . , 4 3 . B . X X O . |
$$ | . . . O . . . . . . . O . . . . . O . |
$$ | . . . O . O . X . . . . O . . X X O . |
$$ | . . 1 . . . W . X O O O X . . X O . . |
$$ | . . . . . . . 2 X O X X X . O X O . . |
$$ | . . . X . X X X O X X . . O . X X O . |
$$ | . . X , . . O O O X O X X X X X O O . |
$$ | . . X O . . . . . O O O O O O O X X . |
$$ | . . O . O . . . . . . . . . . X . X . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ ---------------------------------------[/go]


So, when Black plays :b3: and subsequent, all that aji goes to waste and White gets a big center.


Last edited by Knotwilg on Tue Jun 02, 2020 4:56 pm, edited 2 times in total.
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 Post subject: Re: Knotwilg's practice
Post #183 Posted: Tue Jun 02, 2020 4:54 pm 
Gosei
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Posts: 1725
Location: Ghent, Belgium
Liked others: 267
Was liked: 795
Rank: KGS 2d OGS 1d Fox 4d
KGS: Artevelde
OGS: Knotwilg
Online playing schedule: UTC 18:00 - 22:00
Now that we have AI to review, I'd really like to record my thought process. That's the next step. The best I can do is review my game, add what I think I thought, then review. Here's a recent win.


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 Post subject: Re: Knotwilg's practice
Post #184 Posted: Thu Jun 04, 2020 6:15 am 
Gosei
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Posts: 1725
Location: Ghent, Belgium
Liked others: 267
Was liked: 795
Rank: KGS 2d OGS 1d Fox 4d
KGS: Artevelde
OGS: Knotwilg
Online playing schedule: UTC 18:00 - 22:00
I played 10 games on OGS, following "dwyrin's heuristics" aka "basics":

See https://senseis.xmp.net/?Dwyrin

6 - 4 but really 5 - 5 as one was a lost game won +T

Why did I win?

1) lucky, opponent blundered in a fight
2) good splitting attack, finishing off one of the groups, leaving the other weak
3) proper usage of influence to attack, killing a group
4) winning on thickness and proper direction of play
5) convert central influence into territory

Why did I lose?

1) slack play, failure to kill an invading group
2) acquired central influence but failed to kill an invading group
3) wrong play in middle game joseki, downhill from there (opponent played strong)
4) wrong play in opening joseki downhill from there (same)
5) failure to attack for profit

What does this tell me?

1) I remain an influence oriented player
2) I like to fight and kill but that's not always the right idea or shouldn't be the win condition
3) still get better at killing: play sharper moves and read out more variations faster
4) I should learn more joseki
5) I'm performing at my level of comprehension; I didn't make any mistakes which I could easily identify without AI review

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 Post subject: Re: Knotwilg's practice
Post #185 Posted: Tue Jun 30, 2020 5:33 am 
Gosei
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Posts: 1725
Location: Ghent, Belgium
Liked others: 267
Was liked: 795
Rank: KGS 2d OGS 1d Fox 4d
KGS: Artevelde
OGS: Knotwilg
Online playing schedule: UTC 18:00 - 22:00
Reviewing my latest 8 games with KataGo, zooming in on my mistakes and then categorizing them, this is the result:

Fighting/middle game tactics
• Too confident resisting
• Wrong extension in capturing race (reading)
• Missing a chance to simplify, caught up in the fight
• Don’t bail out of a capturing race if you have many more liberties
• Defend higher up the chain

Shape/technique
• Playing a knight’s move for defence
• Disconnect a big group, while there was a better move that threatened to disconnect a part AND destroy the shape
• Don’t give opportunity to profit in sente
• Wrong shape in a joseki follow up (keima i/o kosumi)
• Wrong shape move

Endgame/sente
• Answering locally while the biggest move was elsewhere (deny profit in sente)
• Wrong local move losing sente
• Small, not severe move
• Just defending territory is small

Strategic choices
• Too territorial choice while splitting was better
• Missing a chance to cut off a major group, focusing on central influence instead
• Don’t reinforce the high 2 space enclosure for mere sabaki
• Attack too close to strength, allow to resist

Invasions/reductions
• Play what looks like a reduction (a shoulder hit) but it’s actually too deep an invasion
• Better Invade where the weakest group is
• Don’t invade just for scooping out territory; instead attack the weakest group

Ko
• Should answer a ko threat by playing another ko locally
• Wrongly evaluate winning the ko vs answering ko threat

Life & Death
• Wrongly evaluate a group to be killable, losing sente

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 Post subject: Re: Knotwilg's practice
Post #186 Posted: Thu Jul 02, 2020 5:54 am 
Gosei
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Posts: 1725
Location: Ghent, Belgium
Liked others: 267
Was liked: 795
Rank: KGS 2d OGS 1d Fox 4d
KGS: Artevelde
OGS: Knotwilg
Online playing schedule: UTC 18:00 - 22:00
I'm using a fantastic app, TsumeGo pro, one of the few for which I pay because it's so awesome. After this advertisement, let me discuss one of the problems I solved today.

First some context: there's a daily output of 6 problems, 2 Easy, 2 Medium, 2 Hard. That's spot on for my level: Easy I can solve at a glance, Medium I can always solve with some focus but occasionally make mistakes, Hard I can solve, say 50% of the time.

Here's one of today's hard problems:

Click Here To Show Diagram Code
[go]$$B Black to kill the whole group
$$ -------------------+
$$ . . . . . . c a . |
$$ . . . X X X O . O |
$$ . . . X O O . b . |
$$ . . X X O X O O . |
$$ . . X . O X X O d |
$$ . . . X O O X X . |
$$ . . . . X X X . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |[/go]


More context: I always need to apply myself to solve such a problem thoroughly, not just by clicking.
Solving-by-clicking usually starts at one of the vital points. Here I see A and B.
The systematic approach is to reduce the eyespace first with the hanes of C or D.

Click Here To Show Diagram Code
[go]$$B reduce eyespace 1
$$ -------------------+
$$ . . . . . . 1 2 . |
$$ . . . X X X O . O |
$$ . . . X O O 4 3 . |
$$ . . X X O X O O . |
$$ . . X . O X X O d |
$$ . . . X O O X X . |
$$ . . . . X X X . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |[/go]


We can quickly see how :b1: fails. I would normally not explore this variation: it's useful to discover the vital point of :w2: which I already have discovered.

Click Here To Show Diagram Code
[go]$$B reduce eyespace 2
$$ -------------------+
$$ . . . . . . 4 3 . |
$$ . . . X X X O 7 O |
$$ . . . X O O 6 5 . |
$$ . . X X O X O O 2 |
$$ . . X . O X X O 1 |
$$ . . . X O O X X . |
$$ . . . . X X X . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |[/go]


This line already works. :b3: is played at the vital point because reducing the eye space on that side didn't work. Next we play the other vital point at :b5:. If :w6: at :b7: then we falsify the eye at :w6:. With :b7: we create a known "nakade" using the "special properties of the corner". If :w4: elsewhere, then Black connects his stone and there can't be two eyes. So how about :w2:?


Click Here To Show Diagram Code
[go]$$B reduce eyespace 2
$$ -------------------+
$$ . . . . . . . 2 . |
$$ . . . X X X O . O |
$$ . . . X O O 4 3 6 |
$$ . . X X O X O O 5 |
$$ . . X . O X X O 1 |
$$ . . . X O O X X . |
$$ . . . . X X X . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |[/go]


If :w2: on the vital point, then this line fails for Black

Interestingly though ...

Click Here To Show Diagram Code
[go]$$B reduce eyespace 1
$$ -------------------+
$$ . . . . . . 2 3 . |
$$ . . . X X X O 7 O |
$$ . . . X O O 6 5 . |
$$ . . X X O X O O 4 |
$$ . . X . O X X O 1 |
$$ . . . X O O X X . |
$$ . . . . X X X . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |[/go]


This :w2: reactivates the killing line. We can see that :b3: really is the vital point. So ...

Click Here To Show Diagram Code
[go]$$B main line
$$ -------------------+
$$ . . . . . . 2 1 . |
$$ . . . X X X O 7 O |
$$ . . . X O O 6 5 . |
$$ . . X X O X O O 4 |
$$ . . X . O X X O 3 |
$$ . . . X O O X X . |
$$ . . . . X X X . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |[/go]


... this becomes the main line. :b1: forces :w2: and now :b3: executes the killing shape.


Click Here To Show Diagram Code
[go]$$B variation
$$ -------------------+
$$ . . . . . . 2 1 . |
$$ . . . X X X O 4 O |
$$ . . . X O O 5 b . |
$$ . . X X O X O O a |
$$ . . X . O X X O 3 |
$$ . . . X O O X X . |
$$ . . . . X X X . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |[/go]


:w4: doesn't help: after :b5: A and B are miai.

Click Here To Show Diagram Code
[go]$$B failure
$$ -------------------+
$$ . . . . . . 2 1 . |
$$ . . . X X X O 4 O |
$$ . . . X O O 5 3 6 |
$$ . . X X O X O O . |
$$ . . X . O X X O a |
$$ . . . X O O X X . |
$$ . . . . X X X . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |[/go]


Incidentally, this :b3: doesn't work. After :w6: White can live at :b5: or A.

This problem has a depth of 9 and a width of 8, for me at least. That's quite a hard problem but the systematic approach of it reduces the complexity of the variation tree.


This post by Knotwilg was liked by: Bill Spight
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 Post subject: Re: Knotwilg's practice
Post #187 Posted: Thu Jul 02, 2020 8:13 am 
Gosei
User avatar

Posts: 1725
Location: Ghent, Belgium
Liked others: 267
Was liked: 795
Rank: KGS 2d OGS 1d Fox 4d
KGS: Artevelde
OGS: Knotwilg
Online playing schedule: UTC 18:00 - 22:00
For reference, this is the second hard problem today. It's one that I can almost solve at the spot. There's a clear vital point and I have often enough seen problems where the threat to create an eye by capturing three stones leads to shortage of liberties in the corner. In other words, this is almost an intuitive one for which I won't apply a systematic approach.

Click Here To Show Diagram Code
[go]$$B Black to live
$$-----------------------+
$$ . . . . . . . . . . . |
$$ . . . . . . . . . O . |
$$ . . . . O . O O O . . |
$$ . . . . . O X X . X . |
$$ . . . . . O X . . . . |
$$ . . . . . O X X X X . |
$$ . . . . . . O O O O . |
$$ . . . . . . . . . . . |
$$ . . . . . . . . . . . |[/go]


Now if you do, it goes like this:

Click Here To Show Diagram Code
[go]$$B Increase eyespace 1
$$-----------------------+
$$ . . . . . . . . . . . |
$$ . . . . . . . . . O . |
$$ . . . . O . O O O 2 . |
$$ . . . . . O X X 1 X . |
$$ . . . . . O X . a . b |
$$ . . . . . O X X X X . |
$$ . . . . . . O O O O . |
$$ . . . . . . . . . . . |
$$ . . . . . . . . . . . |[/go]

Failure: A and B miai


Click Here To Show Diagram Code
[go]$$B Increase eyespace 2
$$-----------------------+
$$ . . . . . . . . . . . |
$$ . . . . . . . . . O . |
$$ . . . . O . O O O 1 2 |
$$ . . . . . O X X 3 X . |
$$ . . . . . O X . . . . |
$$ . . . . . O X X X X 4 |
$$ . . . . . . O O O O . |
$$ . . . . . . . . . . . |
$$ . . . . . . . . . . . |[/go]


Fail by reduce

Click Here To Show Diagram Code
[go]$$B Increase eyespace 3
$$-----------------------+
$$ . . . . . . . . . . . |
$$ . . . . . . . . . O . |
$$ . . . . O . O O O . . |
$$ . . . . . O X X 3 X . |
$$ . . . . . O X . 2 . . |
$$ . . . . . O X X X X 1 |
$$ . . . . . . O O O O . |
$$ . . . . . . . . . . . |
$$ . . . . . . . . . . . |[/go]


Only in this 3rd attempt the vital point must be played to invalidate it. :w3: dies in gote ...

Click Here To Show Diagram Code
[go]$$B Increase eyespace 2b
$$-----------------------+
$$ . . . . . . . . . . 8 |
$$ . . . . . . . . a O 7 |
$$ . . . . O . O O O 1 2 |
$$ . . . . . O X X . X 6 |
$$ . . . . . O X . 3 9 4 |
$$ . . . . . O X X X X 5 |
$$ . . . . . . O O O O . |
$$ . . . . . . . . . . . |
$$ . . . . . . . . . . . |[/go]


In the previous attempt, Black can play the vital point and live. See below main line.

Click Here To Show Diagram Code
[go]$$B Increase eyespace 2c
$$-----------------------+
$$ . . . . . . . . . . . |
$$ . . . . . . . . . O . |
$$ . . . . O . O O O 1 4 |
$$ . . . . . O X X 3 X . |
$$ . . . . . O X . 2 . . |
$$ . . . . . O X X X X . |
$$ . . . . . . O O O O . |
$$ . . . . . . . . . . . |
$$ . . . . . . . . . . . |[/go]


So White must kick in :w2 here.


Click Here To Show Diagram Code
[go]$$B Main line
$$-----------------------+
$$ . . . . . . . . . . 8 |
$$ . . . . . . . . a O 7 |
$$ . . . . O . O O O 5 6 |
$$ . . . . . O X X . X 4 |
$$ . . . . . O X . 1 9 2 |
$$ . . . . . O X X X X 3 |
$$ . . . . . . O O O O . |
$$ . . . . . . . . . . . |
$$ . . . . . . . . . . . |[/go]


Which eventually leads back to 2c in a different order. :b1: takes the vital point right away; :w2: takes the next vital point
:b7: is the tesuji, a sacrifice that leads to a shortage of liberties for White. When she connects at :b7: against Black's atari at :b9:, Black A captures all 6 stones. If White doesn't connect, then Black captures three stones to make an eye.


Formally, this problem would have width 6 and depth 11. That probably meets the criteria for "hard". But I can see it instantly, thanks to doing many problems. Now if only real game problems of width 6 and depth 11 were intuitive to me ...

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