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 Post subject: Additional Joseki notes for games 37-46
Post #101 Posted: Sun Jun 19, 2022 8:58 pm 
Dies with sente

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Additional Joseki notes for games 37-46
(Note: these games were played with group tax, which affects opening strategy somewhat)

4-4 point direct 3-3 invasion
Click Here To Show Diagram Code
[go]$$Wc Preferred sequence
$$ --------------------
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . X 1 . . . . . .
$$ | . . 2 O . . . . . ,
$$ | . . 4 5 . . . . . .
$$ | . 6 3 . . . . . . .
$$ | . 8 7 . . . . . . .
$$ | . . 9 . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . , . . . . . ,
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . X . . . . . ,
$$ | . . . . . a . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ --------------------[/go]

There are many ways of dealing with a 3-3 invasion, but in a cross-hoshi fuseki with group tax, the knight's move at :w3: is favored by about 0.2 points. The sequence through :b6: is expected; :w7: may either be as shown or at a.

Actually, the direct 3-3 invasion rarely seems to come up in these games, but I think I might see it if I ever play group tax games against opponents more familiar with modern Go, so this seems worth knowing.

4-4 point, keima approach, side hoshi pincer, tenuki
Click Here To Show Diagram Code
[go]$$Bc Black a is a high priority
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . 1 . . . . . . . 2 a . . . . |
$$ | . . . O . . . . . 3 . . . c . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . b . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . 4 . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |[/go]

Kosumi-tsuke is a famous handicap joseki; when the supporting stone at :b3: is present, a follow-up at a is considered superior to other responses such as b or c.

In this situation in game 41, I played a move elsewhere on the board. But the priority of a is quite high, almost equivalent to playing in an empty corner. So black should play at a.

4-4 point, keima approach supported by side hoshi, side invasion
Click Here To Show Diagram Code
[go]$$Wc :b4: elsewhere
$$ ----------------------
$$ . . . . . . . . . . . |
$$ . . . . . . . . . . . |
$$ . . c 2 b 1 . . . . . |
$$ . O . 3 . . . X . . . |
$$ . . . . . . . . . . . |
$$ . . . . . . . . a . . |
$$ . . . . . . . . . . . |
$$ . . . . . . . . . . . |
$$ . . . . . . . . . . . |
$$ . , . . . . . , . . . |[/go]

Black invades at :b2:, so naturally white covers at :w3:. If black plays elsewhere, what is white's local continuation?

I sort of assumed that making the tiger's mouth at c must be the ideal shape. But b and especially a turned out to be slighly better, at least in the context of my game 42. I will definitely consider these moves in a similar situation, and not just assume that c is the move.

4-4 point, keima approach, attachment
Click Here To Show Diagram Code
[go]$$Bc Options for :w6:
$$ --------------------
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . c 5 . 1 . a . .
$$ | . . 6 O . 2 3 . . ,
$$ | . . . . . 4 b . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . O , . . . . . ,[/go]

Black should continue at a (linking up all stones), or b (possibly sacrificing the corner, but building side influence). Black c was my greedy mistake in game 43.

4-4 point keima approach ōgeima response continuation
Click Here To Show Diagram Code
[go]$$Bc A now-familiar sequence
$$ --------------------
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . 8 1 6 . . .
$$ | . . . O . 4 . . . ,
$$ | . . . . . . . . . .
$$ | . . 5 . 3 . . . . .
$$ | . . 2 7 . . . . . .
$$ | . . a . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . , . . . . . ,
$$ | . . . b . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . X . . . . . ,
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ --------------------[/go]

This sequence is becoming quite familiar to me. Usually black will continue at a, or possibly play an extension such as b.

If black plays elsewhere instead, then white may continue at a. This seems to be more urgent than approaching a 4-4 stone or defending a 4-4 stone, but less urgent than answering a double approach or 3-3 invasion. I tried setting up a position with a 3-4 stone in another corner, and a was considered very slightly less urgent than approaching the 3-4 stone.

Perhaps this seems like a rather fine point to be bringing up, but this sequence really is appearing a lot in my games with group tax, so it is valuable for me to know the priority of this move.

4-4 point, keima approach, ōgeima extension, one-space approach
Click Here To Show Diagram Code
[go]$$Bc White to play
$$ --------------------
$$ | . . . . . . . . . .
$$ | . . . . f . . . . .
$$ | . . . . . 1 . . . .
$$ | . . . O . e . . . ,
$$ | . . . . . c . . . .
$$ | . . . . d b . . . .
$$ | . . 2 . a . . . . .
$$ | . . . . . . . . . .
$$ | . . 3 . . . . . . .
$$ | . . . , . . . . . ,[/go]

A move such as a, b, c, or d would be good. I thought these moves seemed slow and played e, but this was suboptimal.

EDIT: Another interesting move is f. This move happens to appear in Josekipedia. Although the policy model rates this move very low, it only loses 0.20 points compared to a (in the context of my game 46). Furthermore, it is actually 0.71 points better than a in the context of a (somewhat different) position in my game 48, although :b3: is on the fourth line in that game.

Shape point
Click Here To Show Diagram Code
[go]$$Wc White to make shape
$$ | . . . . . . . . . .
$$ | . . . , . . . . . ,
$$ | . . . X 2 b . . . .
$$ | . . . . 1 c a . . .
$$ | . . . . . . d . . .
$$ | . . O O . e f . . .
$$ | . . X . . g . . . .
$$ | . . . X . . X . . ,
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ --------------------[/go]

White is running towards the center, and would like to run with good shape. My move was g, but this is aji keshi. I thought about a, but it felt to me like an incomplete shape.

Click Here To Show Diagram Code
[go]$$Wc Miai
$$ | . . . . . . . . . .
$$ | . . . , . . . . . ,
$$ | . . . X X a . . . .
$$ | . . . . O . 1 . . .
$$ | . . . . . . . . . .
$$ | . . O O . . b . . .
$$ | . . X . . . . . . .
$$ | . . . X . . X . . ,
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ --------------------[/go]

In fact, :w1: is a good move, as either a or b would complete a good shape.


Last edited by hakuseki on Sat Jun 25, 2022 6:05 am, edited 1 time in total.
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 Post subject: Second checklist
Post #102 Posted: Sun Jun 19, 2022 10:39 pm 
Dies with sente

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Here's my second attempt at a checklist.

Code:
Global concerns:
  What is the second-biggest-seeming area?
  Could there be a bigger move there that I haven't checked yet?

Reading:
  Did I think of every possible local move?
  What sequences can follow from each move?
  Which of those outcomes is best?

If I think my move is sente:
  Am I sure that my followup actually works?
  Am I sure that my opponent's defense can't be sente?

Extra questions about defense:
  Do I actually need to defend?
  Which move minimizes aji?
  What are the endgame followups?

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 Post subject: Ten more openings
Post #103 Posted: Thu Jun 23, 2022 10:29 pm 
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I've played ten more openings, and this time I achieved an average point loss of 8.87 points, which is more than 2 points better than my previous result.

This progress gives me hope that I may gain a stone in strength this year.

I'll post a more detailed analysis soon.

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 Post subject: Re: Ten more openings
Post #104 Posted: Fri Jun 24, 2022 7:10 am 
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I mentioned my mistakes totaled about 8.87 points per opening in this last set.

Of these, about 1.1 points were lost to joseki mistakes; about 1.5 points to direction of play mistakes, and about 2.2 points to technique mistakes.

"Technique mistakes" is a sort of vague category, but I am referring to questions like: Should I make a solid or hanging connection? Should I push from behind or run ahead with a keima? Should I hane or extend? Generally, these situations did not involve immediate life and death concerns, so the focus is more on judging shape qualities in a particular context.

There were other mistakes, but these seem sufficient to focus on for now. I will make some more detailed posts with diagrams soon.

I also categorized some moves as "dogma mistakes," by which I mean moves that humans would probably consider reasonable but that don't follow the AI style perfectly. These mistakes were very small, but there were a lot of them, so I wanted to see whether they're worth paying attention to. However, they only totaled about 0.4 points per opening, so I will set this concern aside for now.

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 Post subject: Joseki notes for games 47-56
Post #105 Posted: Sun Jun 26, 2022 3:19 am 
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Joseki notes for games 47-56
(Note: these games were played with group tax, which affects opening strategy somewhat)

4-4 point, keima approach, keima extension, contact play
Click Here To Show Diagram Code
[go]$$Bc How does this joseki finish?
$$ , . . . . . , . . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . . . a 1 . . |
$$ . . . . . . 8 6 9 . |
$$ , . . . . . O 3 7 . |
$$ . . . . 2 . . 4 5 . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ --------------------[/go]

This is very common AI joseki, but sometimes I've forgotten how it ends. White will play a, and then what?

Click Here To Show Diagram Code
[go]$$Wc Continuation
$$ --------------------
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ , . . . . . X . . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ , . . . . . , . . . |
$$ . . . . . . . . . . |
$$ . . . . . . a b . . |
$$ . . . . . . 3 2 . . |
$$ . . . . . . 1 X . . |
$$ . . . . . . O O X . |
$$ , . . . . . O X X . |
$$ . . . . O . . O X . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ --------------------[/go]

I played b but this is too passive. :b4: should either be at a or tenuki. Let's look at both:

Click Here To Show Diagram Code
[go]$$Bc Hane
$$ --------------------
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ , . . . . . X . . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . . . 9 8 . . |
$$ , . . . . . 7 6 . . |
$$ . . . . . . 5 4 . . |
$$ . . . . . . 1 2 3 . |
$$ . . . . . . O X . . |
$$ . . . . . . O X . . |
$$ . . . . . . O O X . |
$$ , . . . . . O X X . |
$$ . . . . O . . O X . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ --------------------[/go]

White will probably cut at :w2:, but this isn't scary for black. Black is happy to just keep pushing like this. There are some other variations, but black's goal will be the same: build a wall.

Click Here To Show Diagram Code
[go]$$Wc Tenuki
$$ , . . . . . , . . . |
$$ . . . . . . . . 3 . |
$$ . . . . . . . 1 2 . |
$$ . . . . . . O X a . |
$$ . . . . . . O X . . |
$$ . . . . . . O O X . |
$$ , . . . . . O X X . |
$$ . . . . O . b O X . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ --------------------[/go]

If black tenukis, white may double hane, but black can simply tenuki again. The black stones will are alive via the miai of a and b.

4-4 point, low approach, kosumi-tsuke transposition
Click Here To Show Diagram Code
[go]$$Bc :b3: tenuki
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . 4 1 . . . . . b c d . . . . . |
$$ | . . . O . 5 . . . 6 . . . . . B . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . 2 . . . . . . . . . . . . . . . |
$$ | . . . . . a . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |[/go]

Various move orders; may result in this shape in the upper-left; this particular order is from my game 47.

Where should black play next? I played a, which I have seen in handicap games. This move would have been correct if the marked stone (the upper right star point) were white, but stronger moves are available in this position. Black should pincer the :w6: stone, for instance with b, c, or d.

4-4 point, low approach, one-space low pincer
Click Here To Show Diagram Code
[go]$$Wc Where should white continue?
$$ | . . . . . . . . . ,
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . b . . . . . . .
$$ | . . . . . a . . . .
$$ | . . . X . . . . . ,
$$ | . . . . . 1 . 2 . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ --------------------[/go]

Here's what I've noticed about how KataGo responds to pincers when playing with group tax:

Generally, white will not invade at the 3-3 point, in contrast to games without group tax, in which case 3-3 invasions are quite common.

In the case of a near pincer (whether on the third or fourth line), the one-space jump at a is good.

For more distant pincers, a double approach or counter-pincer will usually be preferred.

In any case, answering a pincer does not seem be urgent. Tenuki, e.g. to approach another corner, is often the best move.

In my game 48, I played a, but b would have been about 0.4 points better. I also misplayed the continuation, as shown below:

4-4 point, low approach, one-space low pincer, double approach, continuation
Click Here To Show Diagram Code
[go]$$Wc Continuation
$$ | . . . . . . . . . ,
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . 1 . . . . . . .
$$ | . . . . . . . . . .
$$ | . . 5 X a 2 3 . . ,
$$ | . . 7 . 6 O 4 X . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ --------------------[/go]

Even after :b2:, the local situation is not urgent; white would most likely tenuki, then come back and play :w3: later, or perhaps directly invade at :w7: instead. But I think the sequence shown in the diagram is easy to understand. In my game 48, I played the atari at a instead of :w5:, which was a mistake of 2.5 points.

4-4 point, low approach, ōgeima, ōgeima, variation 1
Click Here To Show Diagram Code
[go]$$Bc How should black deal with :w8:?
$$ , . . . . . , . . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . . . . 6 . . |
$$ . . . . . . 4 1 . . |
$$ . . . . 3 . . e . . |
$$ d c b 7 . . O . . . |
$$ . . 8 2 5 . . . . . |
$$ . . . . . a . . . . |
$$ . . . . . . . . . . |
$$ --------------------[/go]

In my previous games, :w8: has been at e, but the move shown here is probably more common. In response, I played :b9: at e, which is not terrible, but the other options shown here are about half a point better.

Black may aim for the corner with a, in which case white will turn at b; otherwise, black may aim to press white down with b, c, or d.

4-4 point, low approach, ōgeima, ōgeima, variation 2
Click Here To Show Diagram Code
[go]$$Bc How should black deal with :w8:?
$$ , . . . . . , . . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . . . 5 . . . |
$$ . . . . . a 4 1 . . |
$$ . . . . 3 . . b . . |
$$ , . . . . . O . . . |
$$ . . . 2 . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ --------------------[/go]

Here's another variation. :b5: is a mistake of about 0.5 points. :w6: should be at a. I played at b, but this was a mistake of about 2 points.

4-4 point, double approach, contact play, hane, extend, push
Click Here To Show Diagram Code
[go]$$Bc :w2: elsewhere
$$ --------------------
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . 1 . . . .
$$ | . . . O . . . . . ,
$$ | . . . . . . . . . .
$$ | . . 3 4 6 . . . . .
$$ | . . . 5 7 . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . , . . . . . ,[/go]

I find this :b7: rather characteristic of the group tax opening style. Continuation follows.

Click Here To Show Diagram Code
[go]$$Wc Continuation
$$ --------------------
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . b . X . . . .
$$ | . 5 . O 8 . . . . ,
$$ | . 2 1 a . . . . . .
$$ | . 3 X O O 6 . . . .
$$ | . 7 4 X X . . . . .
$$ | . . . . . . . . . .
$$ | . . c . . . . . . .
$$ | . . . , . . . . . ,[/go]

:b8: is not really sente. In my game, I responded at a. The Josekipedia move is b. Both of these are inferior to c. Tenuki is also a good option.

In the case of tenuki, b and c may be considered miai. If black reduces the corner with b, white moves to the side with c. If black instead plays c, or some other move to secure the side, then white takes the corner with b.

4-4 point, approach, low pincer, one-space jump, two-space jump
Click Here To Show Diagram Code
[go]$$Bc :w6: elsewhere
$$ --------------------
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ , . . . . . X . . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ , . . . . . , 5 . . |
$$ . . . . . . . . . . |
$$ . . . . . 8 . 2 . . |
$$ . . . . . . . . . . |
$$ . . . 9 . 3 . 1 . . |
$$ . . a . . . . . . . |
$$ , . . 4 . . O . . . |
$$ . 7 . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ --------------------[/go]

This sequence may favor black slightly. Perhaps :w8: should have been at a. Continuation follows:

Click Here To Show Diagram Code
[go]$$Wc Continuation
$$ --------------------
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . 1 . . . . . |
$$ , . . . d . X . . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . . . e . . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ , . . . . a , X . . |
$$ . . . . . . . . . . |
$$ . . . . . O . O . . |
$$ . . . . . . . . . . |
$$ . . . X . X . X . . |
$$ . . c . . . . . . . |
$$ , . . O . . O . b . |
$$ . X . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ --------------------[/go]

Black has several good responses to :w1:. I played e, but this lukewarm move is not great. The other labeled moves are good.

I'm especially interested in b. This kind of slide under the 4-4 point has fallen off my radar along with the old "4-4 point, keima approach, keima extension, slide" joseki. However, in the context of this pincer fight, it seems to be effective. I've also seen it in other, similar contexts. I'll try to keep it in mind from now on.

4-4 point, approach, two-space high extension, 3-3 invasion
Click Here To Show Diagram Code
[go]$$Wc :w6: elsewhere
$$ --------------------
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . 1 . 4 3 . . |
$$ , . . . . . X 5 . . |
$$ . . . . . . a b . . |
$$ . . . . . . . . . . |
$$ . . . . . . 2 . . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ , . . . . . , X . . |[/go]

In this position, :b6: at a is favored over b by about 0.2 points. I played b because I thought it limited white's movement more and the presence of the :b2: stone would help reinforce black's weakness at a. But this cutting point did end up becoming a problem later in my game 51.

4-4 point, double approach, contact play, hane, extend
Click Here To Show Diagram Code
[go]$$Wc :b2: elsewhere
$$ --------------------
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . 3 . . c . . |
$$ , . . . . . X a . . |
$$ . . . . . . . b e . |
$$ . . . . . 6 4 1 . . |
$$ . . . . . d 5 . . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ , . . . . . , . . . |[/go]

Here are some of white's various options for :w7:, but I'm mainly interested in discussing a and b. When should white choose a and when should white choose b?

I usually play a because I feel it gives me slightly more territory than b. But recently I feel that b damages the :w3: stone less than a. So I should decide whether I want to establish a group on the top side; if so, then I should lean more towards playing b.

4-4 point, inside contact play, inside hane, extend, push
Click Here To Show Diagram Code
[go]$$Bc :w2: elsewhere
$$ --------------------
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . 2 1 3 b . . . .
$$ | . . . O 4 a . . . ,
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . , . . . . . ,[/go]

Here's a sequence from my game 56. I played as white here. In the context of a mostly-empty board, :b1: seems a bit premature. For :w2:, either the inside or outside hane is fine; I've also seen other whole-board situations where the outside hane was preferred. I played :w4: because it felt to me like a move AI would play; this was correct, but I did not really understand the meaning of this move and I made mistakes in the continuation.

In particular, I think if the hane at a were a good move for black, this would suggest that :w4: is bad. However, black should not hane because the cut at b would be severe.

Click Here To Show Diagram Code
[go]$$Bc Continuation; :w2: is incorrect
$$ --------------------
$$ | . . . . . . . . . .
$$ | . . a . . . . . . .
$$ | . . O X X 1 . . . .
$$ | . . b O O 2 3 . . ,
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . , . . . . . ,[/go]

Since black cannot hane, black extends with :b1:. My push at :w2: was a mistake, because this time black can hane at :b3: and the cut is less severe. Instead of continuing to push, white should have defended the corner with a move such at a or b.

The mistakes discussed above accounted for an average of 1 lost point per game within this set of ten openings.

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 Post subject: Humanlike AI opponents?
Post #106 Posted: Mon Jun 27, 2022 3:29 am 
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I tried playing an opening (up to move 46) against the AI from the Play Go Against a DCNN page.

My mistakes totaled 17.3 points (and the AI's mistakes totaled 17.4 points). Actually, it was mostly the same mistake, as we both kept ignoring the most urgent point on the board.

I am not sure if I will bother to post a review, but I think it is worth noting that just because I have reduced my point loss against one AI does not mean I have improved by a similar amount in general.

At some point I'd like to practice more openings against the linked AI or something similar, i.e. a policy model trained to emulate human players. I'd be interested in alternatives to the site I linked, because it doesn't provide a way to download an SGF, so I'm left to transcribe it by hand.

Also, this reminds me that I wanted to talk about metrics a bit. I've been judging my performance purely in terms of point loss, but I think this may have drawbacks. For instance, it may lead me to avoid difficult variations, even if they would be equally difficult for my opponent.

I am considering a new metric where I would subtract half my opponent's score loss from my score loss, so e.g. if my point loss is 20 points and my opponent's is 6, then my adjusted point loss would be 17 points. This would help encourage me to play variations that are difficult for my opponent, and also penalize me less when both players repeatedly fail to notice something.

I won't be adopting this immediately, however, as I still need to finish my current kifu study project, and changing metrics mid-way through would just be confusing.

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 Post subject: Technique notes for games 47-56
Post #107 Posted: Thu Jun 30, 2022 5:49 am 
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I'm about halfway through writing up these notes, but I feel like it is taking too long and I'd like to move on to playing more games, so I may not finish.

Anyway, while playing my next set of openings I'd like to focus on the following questions:
:b1: Am I moving in the right direction? / Am I approaching from the right direction?
:w2: Am I using the right technique?

Here are my incomplete technique notes:

Technique notes for games 47-56
(Note: these games were played with group tax, which affects opening strategy somewhat)

Surrounding is better than approaching
Click Here To Show Diagram Code
[go]$$B :b1: should be at a
$$ --------------------
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . O B . . . .
$$ | . . . W . X . . . O
$$ | . . . . . . . . . .
$$ | . . . W . . . . . .
$$ | . . . . . X . . . .
$$ | . . 1 a . . . . . .
$$ | . . . . . . . . . .
$$ | . . . , . . . . . ,[/go]

In this position I played :b1:. My reasoning was as follows: Black approached, and white played a fourth-line extension (see marked stones). A double approach is good in that situation. The extra stones don't matter. In fact, the extra stones do matter, because black has a chance to surround instead of merely approaching. Black should have played at a instead. As it is, :b1: invites white to answer at a, keeping black separated.

Hane a contacting stone
Click Here To Show Diagram Code
[go]$$Wc :b2: should be at a
$$ --------------------
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . O X . . . .
$$ | . . . O . X . . . O
$$ | . . . b 2 . . . . .
$$ | . . . O c 1 a . . .
$$ | . . . . . X . . . .
$$ | . . X . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . , . . . . . ,[/go]

I kind of think I should have addressed this in my joseki review, but I'm including it here anyway. I played :b2: but I should have played at a. Perhaps a hane against a contacting stone is intuitive, and :b2: is weak for black as well as white.

Actually I don't think this is so clear-cut, which is why I now hesitate to discuss this as a "technique" mistake. If white responds at b, as happened in the game, then white has been tricked and the sequence is not bad for black. Instead, white should block at c, but I think this requires deep reading to verify.

Two-space extension to create a base
Click Here To Show Diagram Code
[go]$$Wc :b2: should be at a
$$ --------------------
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . O X . . . .
$$ | . . . O . X . . . O
$$ | . . . O X . . . . .
$$ | . . . O X O . . . .
$$ | . . . 1 . X . . . .
$$ | . . X . . . . . . .
$$ | . . . . . . . . . .
$$ | . . 2 , . . . . . ,
$$ | . . a . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . W . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . X . . . . . ,
$$ | . . . . . . X . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ --------------------[/go]

I am not sure why I played only a one-space extension here, but it should clearly be a two-space extension, both for stability and to pincer white's marked stone.

Capture or connect?
Click Here To Show Diagram Code
[go]$$Wc Should black respond at a or b?
$$ --------------------
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . O X . . . .
$$ | . . . O . X . . . O
$$ | . . . O X b . . . .
$$ | . . . O X O X . . .
$$ | . . . O O X a . . .
$$ | . . X . . 1 . . . .
$$ | . . . . . . . . . .
$$ | . . X , . . . . . ,[/go]

White plays the atari at :w1:. In this case black should connect at a. In this case I think a does more to develop the center; although white's stone is not captured immediately, the remaining aji doesn't seem very useful for white. Still, I played the wrong move of b here, losing 2.4 points.

I think this kind of capture vs. connect situation is interesting, however, because this decision can go either way depending on the surrounding context. I'd like to collect a set of example positions like this to compare these moves. Once I have several such examples I may create a new post.

Click Here To Show Diagram Code
[go]$$Bc Should white extend or jump?
$$ --------------------
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . O . . . . . |
$$ , . . . . . X . . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . . . a . . . |
$$ , . . . . . b . . . |
$$ . . . . . 1 O . . . |
$$ . . . . . X O . . . |
$$ . . . . . X X O . . |
$$ . . . . . . . O . . |
$$ . . . . . . . . . . |
$$ , . . . . . O . . . |
$$ . . . . X . . . . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ --------------------[/go]

Black is pushing from behind. How should white respond?

The answer is the one-space jump at a. This move is faster than a nobi, but it's important to check that the weakness of the one-space jump is not exploitable:

Click Here To Show Diagram Code
[go]$$B If black extends
$$ . . . . . . . . . . |
$$ . . . . . . . 2 . . |
$$ . . . . . . O . . . |
$$ , . . . . 1 , . . . |
$$ . . . . . X O . . . |
$$ . . . . . X O . . . |
$$ . . . . . X X O . . |
$$ . . . . . . . O . . |
$$ . . . . . . . . . . |
$$ , . . . . . O . . . |[/go]


Click Here To Show Diagram Code
[go]$$B If black wedges
$$ . . . . . . . . . . |
$$ . . . . . . . 4 . . |
$$ . . . . . . O . . . |
$$ , . . . . 3 1 2 . . |
$$ . . . . . X O . . . |
$$ . . . . . X O . . . |
$$ . . . . . X X O . . |
$$ . . . . . . . O . . |
$$ . . . . . . . . . . |
$$ , . . . . . O . . . |[/go]


Running technique
Click Here To Show Diagram Code
[go]$$Bc How should white mobilize the marked stone?
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . X . . . . X . . W . . . . . |
$$ | . O . O X . . . . , . . . . . X . . . |
$$ | . X O O . . . . . . . . . . . . . . . |
$$ | . O X O O X . . . . . . . . . X O . . |
$$ | . O X X X . X . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . O . . . |[/go]


Solution follows:

Click Here To Show Diagram Code
[go]$$Wc Nice shape
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . X . . . . X . . O . . a . . |
$$ | . O . O X . . . . , 2 1 . . . X . . . |
$$ | . X O O . . . . . . . . . b . . . . . |
$$ | . O X O O X . . . . . 3 . . . X O . . |
$$ | . O X X X . X . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . O . . . |[/go]

I've previously discussed how this is a nice shape. The 3-3 invasion at a is also a good option. My move was the one-space jump at b, but this is inferior by about 0.4 points.

Click Here To Show Diagram Code
[go]$$Wc Game continuation
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . X . . . . X . . O . . . . . |
$$ | . O . O X . . . . , a d 4 . . X c . . |
$$ | . X O O . . . . . . 3 . . 1 5 . 2 b . |
$$ | . O X O O X . . . . . . . . . X O . . |
$$ | . O X X X . X . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . O . . . |[/go]

Actually every white move here is a mistake. :w3: should perhaps be at a. But I will especially remember that :w5: is aji keshi. Black will connect against the peep, which removes the possibility of a later atari by white stones at b and c. Instead, the kosumi-tsuke at d is a tesuji to make shape.

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 Post subject: Ten more openings
Post #108 Posted: Fri Jul 01, 2022 5:42 pm 
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I've played another ten openings. This time my average loss was about 12.88 points. This is 4.01 points worse than my result in my previous set of 10 games. I might attribute this apparent step backwards to such causes as:

:b1: Too much time spent reviewing instead of playing.
:w2: Focusing less on defense. In my previous set of games, I made few mistakes on defense, which led me to think I didn't need to focus on it as much. But after changing my focus, I am making more defense mistakes.
:b3: Frequently ignoring approaches to approach a different corner. This is not wrong but may lead to a more complex opening with more mistakes.
:w4: Playing while tired.
:b5: Too small sample size.

Anyway, I would like to try to replicate my previous result of 8.87 points lost, on average, in the opening. That's already a big improvement compared to a month or two ago, so I would be happy if I could consistently achieve it. I will try following the same checklist I used in that set, and play more games, perhaps 30.


This post by hakuseki was liked by: Elom0
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