Life In 19x19
http://lifein19x19.com/

Shapes to remember (SDK level)
http://lifein19x19.com/viewtopic.php?f=48&t=16894
Page 2 of 5

Author:  jlt [ Mon Dec 16, 2019 1:22 am ]
Post subject:  Re: Shapes to remember (SDK level)

Position #12.

In this game, I was white, 7k EGF, playing against 2k EGF. This game showed how weak my endgame is: Katago estimates that I was leading by 10 points/91% winrate at move 147, and yet I lost by 15.5 points. :shock:

White to play and make a good endgame move.

Click Here To Show Diagram Code
[go]$$Wc White to play
$$ ---------------------------------------
$$ | . . . . . . . . . . X . . . . . . . . |
$$ | . . . . . . X . X X O O O . . . . . . |
$$ | . . O X . . O X X O X O . O . . O O . |
$$ | . . O X . X X O O O X O X . O O X X . |
$$ | . O X . . . O . . X X . . . . X . X . |
$$ | . O X . . . . . O . . O O X . X X . . |
$$ | . O X . . . . . O . . . O O X . X X . |
$$ | O X X . X X O . . . . . . X O O . O O |
$$ | . O X O O X O . . . . . . . . . O X . |
$$ | . O . , X O . . . , . . . . O , X . X |
$$ | . . . X X O . O . O . X . . . . . X . |
$$ | . . X . X O . . . . . . . . . X . . . |
$$ | . . X X O X X . X . . . . . . . . . . |
$$ | . . X O O . . . . . X . . . . . X . . |
$$ | . X X X X X . O O O O . . . . . . . . |
$$ | . X O O O O . O X X O O . . . O . X . |
$$ | . O O X X . O X X X X O . O . . O . . |
$$ | . . . . . X X O O X . X O . . . . . . |
$$ | . . . . . . . . . . X . . . . . . . . |
$$ ---------------------------------------[/go]


Katago says that White should start with the exchange a-b, then play c.
Click Here To Show Diagram Code
[go]$$Wc
$$ ---------------------------------------
$$ | . . . . . . . . . . X . . . . . . . . |
$$ | . . . a b . X . X X O O O . . . . . . |
$$ | . . O X . . O X X O X O . O . . O O . |
$$ | . . O X . X X O O O X O X . O O X X . |
$$ | . O X . . . O . . X X . . . . X . X . |
$$ | . O X . . . . . O . . O O X . X X . . |
$$ | . O X . . . . . O . . . O O X . X X . |
$$ | O X X . X X O . . . . . . Y O O . O O |
$$ | . O X O O X O . . . . d . . . . O X . |
$$ | . O . , X O . . . , . . . . O , X . X |
$$ | . . . X X O . O . O . B . . . . . X . |
$$ | . . X . X O . . . . . . . . c X . . . |
$$ | . . X X O X X . X . . . . . . . . . . |
$$ | . . X O O . . . . . X . . . . . X . . |
$$ | . X X X X X . O O O O . . . . . . . . |
$$ | . X O O O O . O X X O O . . . O . X . |
$$ | . O O X X . O X X X X O . O . . O . . |
$$ | . . . . . X X O O X . X O . . . . . . |
$$ | . . . . . . . . . . X . . . . . . . . |
$$ ---------------------------------------[/go]


My reasoning was that :bc: threatens to enter my moyo, and at the same time to pull out the :bt: stone, so I protected at d. Katago says it loses "5 points". A better way of playing is to make sente moves starting with "c", which threaten to swallow :bc:, and protect the moyo afterwards. There are several lines of play, here is a simple one:

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

Author:  Knotwilg [ Mon Dec 16, 2019 2:13 am ]
Post subject:  Re: Shapes to remember (SDK level)

What I learnt from pro games is that in the early endgame it's not so much about points but about life and death. In the late endgame it's easier to calculate what is sente and what is the biggest gote. In the early endgame there are so many mutual implications that this is harder. So one first needs to identify the areas where there is or will be major impact on groups, whether they are immediately sente or not.

Attemmpt:

Click Here To Show Diagram Code
[go]$$Wc White to play
$$ ---------------------------------------
$$ | . . . . . . . . . . X . . . . . . . . |
$$ | . . b . . . X . X X O O O . . . . . . |
$$ | . . O X . . O X X O X O . O . . O O . |
$$ | . . O X . X X O O O X O X . O O X X . |
$$ | . O X . . c O . . X X . . . . X . X . |
$$ | . O X . . . . . O . . O O X . X X . . |
$$ | . O X . . d . . O . . . O O X . X X . |
$$ | O X X . X X O . . . . . . X O O g O O |
$$ | . O X O O X O . . . . . . . . . O X . |
$$ | . O . , X O . . . , . . . . O , X . X |
$$ | . . . X X O . O . O . X . . . . . X . |
$$ | . . X . X O . . . . . . . f . X . . . |
$$ | . . X X O X X . X e . . . . . . . . . |
$$ | . . X O O . . . . . X . . . . . X . . |
$$ | . X X X X X . O O O O . . . . . . . . |
$$ | . X O O O O . O X X O O . . . O . X . |
$$ | . O O X X . O X X X X O . O . . O a . |
$$ | . . . . . X X O O X . X O . . . . . . |
$$ | . . . . . . . . . . X . . . . . . . . |
$$ ---------------------------------------[/go]


The border plays that jump to the eye are A and B. A s simply large. B may have that particular quality of impacting the life of the corner group. At first glance if Black plays there it will be sente or at least have large follow-ups.

There is aji to exploit at C and D but nothing major and these moves may be kind of miai.

There are cuts at E and F to make something of the center, but it's probably small.

And then there is G. It makes 6 points already, the shape becomes better, and most of all it cuts Black into two groups. Now both of them are alive but later White will have sente moves against both of them.

I'm not sure this is the best move, but when leading it seems good enough to ensure victory.

Author:  jlt [ Mon Dec 16, 2019 3:06 am ]
Post subject:  Re: Shapes to remember (SDK level)

@Knotwilg: I didn't try all your moves, but according to Katago, "b" is not bad, while "a" and "g" are even worse than the move I played in my game.

Here is the game, in case someone would be interested.



Attachments:
game.sgf [1.96 KiB]
Downloaded 460 times

Author:  Knotwilg [ Mon Dec 16, 2019 6:16 am ]
Post subject:  Re: Shapes to remember (SDK level)

jlt wrote:
@Knotwilg: I didn't try all your moves, but according to Katago, "b" is not bad, while "a" and "g" are even worse than the move I played in my game.


To be fair to myself, I thought B was too trivial to be worthy of exercise, so I looked for something more interesting. With hindsight G is not sente and neither will it bring about much sente against any of the separated groups. B is a sente border play for Black and White has a good follow-up if Black doesn't answer.

Nice endgame exercise!

Author:  jlt [ Thu Jan 02, 2020 8:53 am ]
Post subject:  Re: Shapes to remember (SDK level)

Position #13: this one should be obvious but both players, IGS 6k, got it wrong.

Black to play. What are the next few moves?

Click Here To Show Diagram Code
[go]$$Bc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . O . O . . |
$$ | . . O . O X . . . . X X . O . O X . . |
$$ | . . . , . X . . X X O X O . O X X . . |
$$ | . . . . . . . X . O O O X . X . . . . |
$$ | . . . O . X . . O . . . X . . X O . . |
$$ | . . . . . X O . . . O . . . . . . . . |
$$ | . . X . X . . . . . . . X . . . . . . |
$$ | . . . . . . . O . . O . . . . . X O . |
$$ | . . O , . . . . . , . . X . . , . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . O . X . . . . . , . . . . . , O . . |
$$ | . . X . . X . . . . . X . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


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


And then tenuki! Losing sente so early in the game by capturing at T11 is evil!

(In the actual game, Black captured at T11, which is 4-point mistake according to Katago, but then White protected the cut at P10, which is an equally big mistake...)

Author:  TelegraphGo [ Thu Jan 02, 2020 9:39 am ]
Post subject:  Re: Shapes to remember (SDK level)

I thought this was going to be about black trying this common shape:

Click Here To Show Diagram Code
[go]$$Bc Black is overexcited.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . O . O . . |
$$ | . . O . O X . . . . X X . O . O X . . |
$$ | . . . , . X . . X X O X O . O X X . . |
$$ | . . . . . . . X . O O O X . X . . . . |
$$ | . . . O . X . . O . . . X . . X O . . |
$$ | . . . . . X O . . . O . . . . . . . . |
$$ | . . X . X . . . . . . . X . . . . . . |
$$ | . . . . . . . O . . O . . . . . X O . |
$$ | . . O , . . . . . , . . X . . , 2 1 . |
$$ | . . . . . . . . . . . . . . . . O 3 . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . O . X . . . . . , . . . . . , O . . |
$$ | . . X . . X . . . . . X . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


If white backs off at S8, this is an improvement on the game. So a fight's about to go down! But unfortunately, black doesn't have the strength to do this here. How does white win the fight?

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


Compared to the game variation, black is worse and white is better. It's a disaster. The reason things fell apart was white's one random stone at R14 enabling a ladder that forces black to play 2 as shown instead of at a. The followup at a was black's intent when they extended under like this - preventing it means white is better. This is such a clean example of middlegame fighting shape, I was positive it was close to the game until I opened your hide tag :lol:

Author:  jlt [ Wed Jan 15, 2020 2:04 am ]
Post subject:  Re: Shapes to remember (SDK level)

Position #14: this one should be easy. Edit: I forgot to say that it was White to move, thanks dfan.

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


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


Split Black into two weak groups. Yes there is a cut at a, but it is not urgent right now.

Author:  dfan [ Wed Jan 15, 2020 6:19 am ]
Post subject:  Re: Shapes to remember (SDK level)

White to move, for anyone was wondering but didn't feel like counting the stones.

Author:  jlt [ Tue Feb 04, 2020 3:53 pm ]
Post subject:  Re: Shapes to remember (SDK level)

Position #15: White to play.

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


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


Yes there is a push and cut, but Black needs to take gote to capture two stones, so the following variation is good for White:

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


Black may try the other cut
Click Here To Show Diagram Code
[go]$$Wc
$$ ---------------------------------------
$$ | . . . . . 7 . . . . . . . O . . . . . |
$$ | . . X . 5 4 3 6 8 . . . O . O X X X . |
$$ | . . . . O O 2 O . 9 . . . O X O O O . |
$$ | . . X , . X X 1 . , . . . . X X X . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . X . . . . . . . . . . . . . . |
$$ | . . O O . . O . . . . . . . . . . . . |
$$ | . . X . O . . X . . . . . . . . . . . |
$$ | . . . X O . . . . , . . . . . , . . . |
$$ | . . . X O . O . . . . . . . . . . . . |
$$ | . . . . X O . . . . . . . . . O . . . |
$$ | . . . . X . . . . . . . . . O . O . . |
$$ | . . X . . . . . . . . . . . O O X . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . X . O . . . . . , . . . . . O X . . |
$$ | . . O . . O . . . . . . . X . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


The liberty race is favorable to White, but if this is too scary, then playing :w5: at :b6: is also possible, although slighty less good.

Author:  jlt [ Sun Feb 16, 2020 7:22 am ]
Post subject:  Re: Shapes to remember (SDK level)

Position #16. White to play.

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


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


Do not connect around "a", but attack on a large scale. Black doesn't have time to play at "a" yet.

Author:  jlt [ Fri Apr 17, 2020 8:58 am ]
Post subject:  Re: Shapes to remember (SDK level)

Position #17. I was White, 6k+ on IGS, playing a 2-stone handicap game against a 7k.

Click Here To Show Diagram Code
[go]$$Wc White to play
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O X . . . . . . . . . . . O X . |
$$ | . . O X X O . . . . . X . . . X O X . |
$$ | . . O X . . . . X , . . . X . X O X . |
$$ | . . . X . . . . . . . . . . . X X O . |
$$ | . . O X . . . . . . . . . . . O O . O |
$$ | . . O O . . . . . . . . . . . . . O . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . O X O . . |
$$ | . . . , . . . . . , . . . X O X . . . |
$$ | . . . . . . . . . . . . O O X . X . . |
$$ | . . . . . . . . . . . . X O X . . . . |
$$ | . . . . . . . . . . . O O X X . . . . |
$$ | . . X . X . . . . . . . X O . . O . . |
$$ | . . . . . . . . . . . . . O . . . . . |
$$ | . . . X X O . . . , . . . . . O . . . |
$$ | . X X O X O . . . . X . . X . . O . . |
$$ | . . O O O . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


Hint: Black's last move was

Q11


Answer:

Do not block at Q12, otherwise Black can atari at P12, then at R12, then capture R11.

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


Extend at :w1:. Do not be afraid of Black's push :b2:, continue with :w3:.
White doesn't have eyes, but is pretty safe and has a strong wall in the center. The marked white stone is not dead, so Black is not safe either and needs to add a defensive move at "a" or "b".

Author:  Uberdude [ Sun Apr 19, 2020 9:09 am ]
Post subject:  Re: Shapes to remember (SDK level)

jlt, I will add my own example in a similar vein to your collection if you don't mind. Sdk should be able to get it right, but I got it wrong in a handicap game I just played. I had correctly assumed my shape was connected, but when my opponent played a move which shouldn't have worked my shape intuition was wrong and I answered too quickly and boom, I made a 20+ point mistake and lost the game.

Click Here To Show Diagram Code
[go]$$Bc White to connect
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O O . . . . . . . . X X O O . . |
$$ | . . O X X X X X . X X X X O X O X . . |
$$ | . . O O O O X . X , . . X O O X O O . |
$$ | . . X X X O O X O X X X O . . X . . . |
$$ | . . X . . X . . . . O X O . O . X . . |
$$ | . O X X X . . . . X . O O . . . . . . |
$$ | . O X . . . . . . . . 3 . . X X X . . |
$$ | . . O X . . X . O 1 . . . . X O O X . |
$$ | . O . X . . . . . 2 O O . . X X O X . |
$$ | . . O O . . . . . O X . . . X O . O X |
$$ | . O X . X . . . . O X . O X X O O . O |
$$ | . O X . X . . . . O X X X X O O O O . |
$$ | O X O O X . X X . O O X O . O X O X O |
$$ | O X X . . . X O O O X O O . O X O X X |
$$ | . O X X X X O X X , X X O . O X X . X |
$$ | . O O O X O O O X . X O . O O O X X . |
$$ | . . . . O O O X . . X O . . O X X . X |
$$ | . . . . . . . X . . . . O O . . . . . |
$$ ---------------------------------------[/go]


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


Click Here To Show Diagram Code
[go]$$Bc Fine
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O O . . . . . . . . X X O O . . |
$$ | . . O X X X X X . X X X X O X O X . . |
$$ | . . O O O O X . X , . . X O O X O O . |
$$ | . . X X X O O X O X X X O . . X . . . |
$$ | . . X . . X . . . . O X O . O . X . . |
$$ | . O X X X . . . . X . O O . . . . . . |
$$ | . O X . . . . . . . 4 3 . . X X X . . |
$$ | . . O X . . X . O 1 . . . . X O O X . |
$$ | . O . X . . . . . 2 O O . . X X O X . |
$$ | . . O O . . . . . O X . . . X O . O X |
$$ | . O X . X . . . . O X . O X X O O . O |
$$ | . O X . X . . . . O X X X X O O O O . |
$$ | O X O O X . X X . O O X O . O X O X O |
$$ | O X X . . . X O O O X O O . O X O X X |
$$ | . O X X X X O X X , X X O . O X X . X |
$$ | . O O O X O O O X . X O . O O O X X . |
$$ | . . . . O O O X . . X O . . O X X . X |
$$ | . . . . . . . X . . . . O O . . . . . |
$$ ---------------------------------------[/go]

Author:  jlt [ Sun Apr 19, 2020 9:54 am ]
Post subject:  Re: Shapes to remember (SDK level)

Interesting problem. I think another move works.

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

Author:  Bill Spight [ Sun Apr 19, 2020 10:04 am ]
Post subject:  Re: Shapes to remember (SDK level)

Click Here To Show Diagram Code
[go]$$Wc Stubborn resistance
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O O . . . . . . . . X X O O . . |
$$ | . . O X X X X X . X X X X O X O X . . |
$$ | . . O O O O X . X , . . X O O X O O . |
$$ | . . X X X O O X O X X X O . . X . . . |
$$ | . . X . . X . . . . O X O . O . X . . |
$$ | . O X X X . . . . X 3 O O . . . . . . |
$$ | . O X . . . . . 7 5 1 B 2 . X X X . . |
$$ | . . O X . . X . O B 4 6 . . X O O X . |
$$ | . O . X . . . 9 8 W O O . . X X O X . |
$$ | . . O O . . . . 0 O X . . . X O . O X |
$$ | . O X . X . . a . O X . O X X O O . O |
$$ | . O X . X . . . . O X X X X O O O O . |
$$ | O X O O X . X X . O O X O . O X O X O |
$$ | O X X . . . X O O O X O O . O X O X X |
$$ | . O X X X X O X X , X X O . O X X . X |
$$ | . O O O X O O O X . X O . O O O X X . |
$$ | . . . . O O O X . . X O . . O X X . X |
$$ | . . . . . . . X . . . . O O . . . . . |
$$ ---------------------------------------[/go]

a = :w11:

Author:  jlt [ Tue Apr 21, 2020 9:51 am ]
Post subject:  Re: Shapes to remember (SDK level)

Position #19. White to play.

Click Here To Show Diagram Code
[go]$$Wc White to play
$$ ---------------------------------------
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . O . O X . . . . . . . . . . . . . . |
$$ | . . O X . X . . . . . . . . . . . . . |
$$ | . . O , . . . X . X . . . . . O . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . X . . . . . . . . . O O O . . |
$$ | . . . X . . . . . . . . X . X X . . . |
$$ | . . . . . O . . . . O . . . . . X . . |
$$ | . . . . . O X . . . . O . . . X . . . |
$$ | . . X X X O . X . X . . . . O O X X . |
$$ | . . O O . O . . . . . O . . . . O O . |
$$ | . . . . . O X . . . X O . . . . . . . |
$$ | . . . . . . . . . . X X O . . . . . . |
$$ ---------------------------------------[/go]


Possible answer.

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


In the game I played b, but Katago thinks it is 5 points worse than :w1:. If Black chooses to respond locally at :b2:, then Black only has one eye. Instead of playing :b2: at K2, Black may prefer to escape at c.

Author:  jlt [ Wed Apr 22, 2020 12:42 pm ]
Post subject:  Re: Shapes to remember (SDK level)

I got promoted to IGS 5k after an undeserved victory: my opponent resigned while being 1 point ahead according to KataGo. Anyway, here is a joseki question, extracted from the game. The answer should be pretty obvious, but I was careless and played a wrong move. In general I play the opening quite fast in order to save time for the middle game but that's probably a bad habit, it would be better to consider several possible josekis and choose the most appropriate one.

Position #20: Black to answer locally.

Click Here To Show Diagram Code
[go]$$Bc Black to play
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . W . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . O . . . . . . . . . . . O X . . |
$$ | . . O , . . . . . , . . . . . , X . . |
$$ | . . . . X . . . X . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


Answer:
Click Here To Show Diagram Code
[go]$$Bc Correct answer
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . . . 1 2 O . . |
$$ | . . . O . . . . . . . . . . . O X . . |
$$ | . . O , . . . . . , . . . 3 . , X . . |
$$ | . . . . X . . . X . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


(It is also possible to tenuki and approach at F17, both moves are equivalent according to KataGo.)

In the game I played at O3 but that's too low, all my stones on the bottom side were on the third line. Black needs to get to the center!

Author:  jlt [ Mon Apr 27, 2020 9:58 am ]
Post subject:  Re: Shapes to remember (SDK level)

After winning 15/15 games on Fox at 3k level, I got double-promoted to 1k... but then I was afraid that the games would become too difficult so I came back to my 2k Tygem account, to see if I get stuck or if I can manage to rank up there as well.

In the following position I didn't see immediately that Black can play at "a" (White cannot respond at "b", otherwise Black plays "c") but that's not my point. The question is: how to attack White's two stones on the bottom. The answer is rather elementary but I didn't find it during the game.

Position #21: Black to attack the marked white group.

Click Here To Show Diagram Code
[go]$$Bc Black to attack the marked stones
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . O O O . O O . O O X . . . . . X . . |
$$ | . X O X . . X O O X X . . . . X . O . |
$$ | . . X X . . X X X O . . . . . . . . . |
$$ | . . . X . . . . . X . . . . . . O . . |
$$ | . . X O . . . . . . . . . . . X . . . |
$$ | . . X O . O . . O . . . . . X O O . . |
$$ | . O O X O . . O . . . . . . X X O . . |
$$ | . . O X O . O X . , . . . . . O O . . |
$$ | . . O X O . . X . . . . . . . . X . . |
$$ | . O X X . O O X . . . . . . . . . . . |
$$ | . O O X X X X . . . . . . . . . . . . |
$$ | . . X O X . . . . . . . . . . . . . . |
$$ | . . . O X O . . . . . . . . . X . . . |
$$ | . . . O X O X . . , . . . . . , . . . |
$$ | . . c O X X . X . W . . W . . X . . . |
$$ | . . b a . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


Answer:

Click Here To Show Diagram Code
[go]$$Bc That's it
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . O O O . O O . O O X . . . . . X . . |
$$ | . X O X . . X O O X X . . . . X . O . |
$$ | . . X X . . X X X O . . . . . . . . . |
$$ | . . . X . . . . . X . . . . . . O . . |
$$ | . . X O . . . . . . . . . . . X . . . |
$$ | . . X O . O . . O . . . . . X O O . . |
$$ | . O O X O . . O . . . . . . X X O . . |
$$ | . . O X O . O X . , . . . . . O O . . |
$$ | . . O X O . . X . . . . . . . . X . . |
$$ | . O X X . O O X . . . . . . . . . . . |
$$ | . O O X X X X . . . . . . . . . . . . |
$$ | . . X O X . . . . . . . . . . . . . . |
$$ | . . . O X O . . . f . b a . . X . . . |
$$ | . . . O X O X . . , c . . . . , . . . |
$$ | . . . O X X . X . W . . W 3 . X . . . |
$$ | . . . . . . . . . . d e 2 1 g . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


:b1: :w2: :b3: expands Black's corner territory while attacking.
After that, White needs to defend at "a" or "b", otherwhite Black will hane at the head of two stones while expanding his corner. White is not safe yet because of the weak point at "c".

In the game I played "f" (after also considering "d" and "e"), thinking this also indirectly protects the cut at H7 but this is not a good attack because White doesn't even need to respond: in case Black plays again in the area, White may still defend at "g" or escape in the center.

Author:  jlt [ Thu May 07, 2020 4:38 am ]
Post subject:  Re: Shapes to remember (SDK level)

Position #22: from a blitz game, White to play. The move is not difficult to find but not high enough in my "policy network".

Click Here To Show Diagram Code
[go]$$Wc White to play
$$ ---------------------------------------
$$ | . O X . O . . . . . . . . . . . . . . |
$$ | X O X X O X . . . . . . . O O . . . . |
$$ | . X X O O X . . . X X . O . X O O . . |
$$ | X X X O . X . . . X O O . . X X X . . |
$$ | O X O . . . . . . . . . . . . . . . . |
$$ | O O . O . . . . . . . . . . . . . . . |
$$ | . . . . . O . . . . . . . . . O . . . |
$$ | . . O . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . X , X . O . . , . . . . . , . X . |
$$ | . . X . X . . . . . . . . . . . O . . |
$$ | . . . X O O . . . . . . . . O . . . . |
$$ | . X X O X . . . . . . O O . . . O . . |
$$ | . O O O . . . . . . . O X X . X O . . |
$$ | . . . . . O . X . . O X . . . X X O . |
$$ | . . . O . . . . . , O X . . . X O O . |
$$ | . . O . . X . . X . . O X X . . X O . |
$$ | . . . X . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


Click Here To Show Diagram Code
[go]$$Wc anti-bump
$$ ---------------------------------------
$$ | . O X . O . . . . . . . . . . . . . . |
$$ | X O X X O X . . . . . . . O O . . . . |
$$ | . X X O O X . . . X X . O . X O O . . |
$$ | X X X O . X . . . X O O . . X X X . . |
$$ | O X O . . . . . . . . . . . . . . . . |
$$ | O O . O . . . . . . . . . . . 1 . . . |
$$ | . . . . . O . . . . . . . . . O . . . |
$$ | . . O . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . X , X . O . . , . . . . . , . X . |
$$ | . . X . X . . . . . . . . . . . O . . |
$$ | . . . X O O . . . . . . . . O . . . . |
$$ | . X X O X . . . . . . O O . . . O . . |
$$ | . O O O . . . . . . . O X X . X O . . |
$$ | . . . . . O . X . . O X . . . X X O . |
$$ | . . . O . . . . . , O X . . . X O O . |
$$ | . . O . . X . . X . . O X X . . X O . |
$$ | . . . X . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


Bumping into an opponent's stone is a move I don't consider enough. This sequence is like bumping, with the order of moves reversed. Maybe this should be called "anti-bumping"?

Author:  jlt [ Thu May 14, 2020 3:08 am ]
Post subject:  Re: Shapes to remember (SDK level)

Position #23: Black to play. What are the interesting areas on the board? In which area should Black play first?

Click Here To Show Diagram Code
[go]$$Bc Black to play
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X O . . . . . . . . . . . . . . |
$$ | . . . X X O . . . O . . . O O X . . . |
$$ | . . . X O O . . . , . . O X . X . . . |
$$ | . . . . . . . . . . . . . X . . X . . |
$$ | . . X X . . . . . . . . . . . X O . . |
$$ | . X O . . . . . . . . . . X X O O . . |
$$ | . . O . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . O . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . X . . . . . . . . . . . . . O O . . |
$$ | . O X X X . . . . , . . O O O X O . . |
$$ | . O O O O X X X . . . X . X X X X . . |
$$ | . . . . . O O . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


Katago's answer:

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


In the game I played directly at :b7: but Katago's suggestion seems to be superior for the following reasons.

First, :b1: is double-sente. If Black doesn't play there, White cuts at :w2:, Black connects with :b3: and White has a forcing move at :b1:.

Then, :b5: takes off White's base and is almost reverse-sente. If Black doesn't play there, White can settle down easily by playing at :b5: himself.

The stone :b1: may help :b7: in the future.

Author:  Bill Spight [ Thu May 14, 2020 3:19 am ]
Post subject:  Re: Shapes to remember (SDK level)

The different areas of the board are not independent, although one is almost so. Anyway, it is still a good idea, I think, to consider how play might go in each identifiable region.

I would have picked the crawl as most urgent.

Page 2 of 5 All times are UTC - 8 hours [ DST ]
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
http://www.phpbb.com/