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Shapes to remember (SDK level) http://www.lifein19x19.com/viewtopic.php?f=48&t=16894 |
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Author: | jlt [ Wed Apr 07, 2021 2:10 pm ] |
Post subject: | Re: Shapes to remember (SDK level) |
Further Katago variations on my third hidden diagram. Suppose that Black plays at B17, then Katago thinks the only move for is B16.
Instead of peeping, Black may want to continue jumping.
In the above diagram, White may want to connect underneath at "a" for , this is slightly less good. In any case, Black cannot push and cut
White can save the 5 stones with "a" at any time. Edit: last diagram corrected. |
Author: | jlt [ Thu May 13, 2021 2:53 pm ] |
Post subject: | Re: Shapes to remember (SDK level) |
Really a shape problem. Position #49, White to play. What is White's next move, and what is the continuation?
Answer:
White cannot kill the three stones, at least not immediately. strengthens the three white stones so that White can aim at attacking one of the black groups later. For instance if Black doesn't defend the group on the right, then "a" will be a good point for White. If Black doesn't defend the two stones then "b" will be a good point for White. |
Author: | Bill Spight [ Fri May 14, 2021 6:48 am ] |
Post subject: | Re: Shapes to remember (SDK level) |
Edit: Nevermind. I assume that the following is the correct diagram for the last one in #81..
White can save the 5 stones with "a" at any time. |
Author: | jlt [ Fri May 14, 2021 7:33 am ] |
Post subject: | Re: Shapes to remember (SDK level) |
Yes indeed, there were two in the diagram, I forgot to erase one. I edited my post according to your comment. |
Author: | jlt [ Fri Jun 11, 2021 3:40 am ] |
Post subject: | Re: Shapes to remember (SDK level) |
Position #50, White to play. Shouldn't be hard but I missed it.
Answer:
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Author: | jlt [ Fri Jun 11, 2021 10:56 pm ] |
Post subject: | Re: Shapes to remember (SDK level) |
Yet another simple move. Position #51, White to play. There are several possible good moves, the question is how to attack/put pressure on the group K16.
Answer: In fact, many good moves are available on the board:
I am mostly interested in move "a" which attacks Black's shape. Katago expects Black to just answer and then White takes a big point elsewhere.
For move , White shouldn't make a move around N17: the upper right corner doesn't need to be protected since it is completely alive (for instance, a black move at O18 wouldn't be sente), and since Black has strenghthened his group with , a white move around N17 won't put a lot of pressure so Black won't respond. Black can't play at O18, otherwise we get the following sequence:
and then White a, Black b, White c follow. |
Author: | jlt [ Fri Jul 23, 2021 12:59 am ] |
Post subject: | Re: Shapes to remember (SDK level) |
Position #52, from an OGS 1k vs. 2k game. Black to play an endgame move.
Katago's answer:
White is not alive yet so is sente. After , Black aims at a. If Black doesn't play at then a sequence like this can happen:
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Author: | jlt [ Sat Jul 24, 2021 1:52 am ] |
Post subject: | Re: Shapes to remember (SDK level) |
Position #53, White to play.
Two moves are possible:
The cut isn't a problem:
So Black would rather play from the other group:
However if Black decides to jump then White can protect the cut:
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Author: | jlt [ Wed Aug 04, 2021 12:26 am ] |
Post subject: | Re: Shapes to remember (SDK level) |
Position #54, Black to play. Several good moves are possible, find a good move in the bottom part of the board.
Black needs to find a good way to use the dead marked stones. In the game I played "b", which loses 2.5 points according to Katago. The move "a" is better since it expands further towards the center. The move "b" is about as good as "a". |
Author: | jlt [ Sun Aug 15, 2021 2:55 am ] |
Post subject: | Re: Shapes to remember (SDK level) |
Position #55:
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Author: | kvasir [ Sun Aug 15, 2021 4:37 am ] |
Post subject: | Re: Shapes to remember (SDK level) |
I am not confident about going directly to 3 but black is unlikely to play 2 |
Author: | jlt [ Thu Aug 19, 2021 12:46 am ] |
Post subject: | Re: Shapes to remember (SDK level) |
Position #56: how to respond to the crosscut?
Answer
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Author: | jlt [ Mon Aug 23, 2021 9:37 am ] |
Post subject: | Re: Shapes to remember (SDK level) |
Position #57, another shape move, from a Fox 2d game. White to play.
Answer:
Black can't save the two stones, the following diagram is horrible for Black:
Position #58: White to play.
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Author: | Farodin [ Sat Sep 18, 2021 4:32 am ] |
Post subject: | Re: Shapes to remember (SDK level) |
I counted black to be slightly ahead in this position, so white has to do something active.
I think white should jump in at , breaking the large knight's move. If black resists with and so on, black suddenly finds himself with 3 weak groups on the board (top left, top center, right side), while white on the top right looks stable enough to not be a big burden in the upcoming fight.
So I think black can't resist, and has to pull back at to connect his stones. White does likewise with . After this, I think white can even afford to play at immediately, since the black group is now unsettled. After this sequence the territory balance swings back into white's favour. |
Author: | jlt [ Sat Sep 18, 2021 1:03 pm ] |
Post subject: | Re: Shapes to remember (SDK level) |
Farodin found the blue move. Position #59, White to play. From a game I played in my club. How to respond to the last move?
Answer: Do not connect passively at Q15!
Later if Black wants to pull out the peeping stone, the local continuation looks like this
Black will probably need to add a move at "a" later. If instead of Black lives in the corner immediately, a local continuation like this may be played.
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Author: | jlt [ Mon Jan 03, 2022 6:04 am ] |
Post subject: | Re: Shapes to remember (SDK level) |
Position #60, Black to play. A rather basic shape, how could I miss it?
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Author: | dhu163 [ Mon Jan 03, 2022 7:47 am ] |
Post subject: | Re: Shapes to remember (SDK level) |
J6 prevents the double peep and helps H7 while damaging J5. W does have aji to cut through imminently with K5 L6 L4, but if required, B even has M7 in half sente (damaging the right), but allowing a locally efficient connection with M5 bamboo. |
Author: | Knotwilg [ Mon Jan 03, 2022 9:09 am ] |
Post subject: | Re: Shapes to remember (SDK level) |
Read the same as dhu and now wondering about this:
Allowing the capture at A is probably too much to bear An amusing after thought with KataGo:
Where to play now as Black? I don't know if the tesuji has a name |
Author: | jlt [ Mon Jan 03, 2022 9:59 am ] |
Post subject: | Re: Shapes to remember (SDK level) |
Thanks for your remarks, you indeed found the same first move as Katago:
(If is at a then is at making miai of capturing one stone or another.) Katago doesn't seem to care much about the marked black stone. I don't understand its variations as they are rather complicated but it seems it wants to make a strong central group in order to attack either marked white group. Here is for instance a simple variation which is considered as good for Black:
however H5 seems to be a vital point that Katago wants to play at almost every move. |
Author: | jlt [ Mon Jan 03, 2022 10:09 am ] |
Post subject: | Re: Shapes to remember (SDK level) |
P.S. For your last question, I thought about this tesuji but I am not sure it works.
https://senseis.xmp.net/?AngleWedge |
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