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Review Request
http://prod.lifein19x19.com/viewtopic.php?f=4&t=15643		 Page 1 of 1
Author:  BlindGroup [ Sat Apr 21, 2018 4:24 pm ]
Post subject:  Review Request
I haven't posted a game for a few months. I've been dealing with some health issues that seriously affect my ability to concentrate. I think I actually lose about 3-4 stones when I'm feeling poorly. But today I felt well, and I played one of those games where I'm fairly sure that my opponent resigned a won game.

I think the game was fairly even until black 89, the losing move. If someone would be willing to take a look at this, I'd be grateful.

In particular, I'm hoping for comments on moves 19, 39, 51, and 73, and to get a sense of whether my analysis of the ko at the end is correct. But of course, I'm happy to get any comments I can get!



Attachments:
2018-04-21 W OGS 3k.sgf [3.38 KiB]
Downloaded 690 times
Author:  dfan [ Sat Apr 21, 2018 4:48 pm ]
Post subject:  Re: Review Request
Welcome back!

:b19:: In my experience, this sort of shape (backing off with a jump in a place where you and your opponent are elbowing each other in close contact, and you are pretty strong) is never right. Whenever my opponent plays like this my eyes light up. This move in particular feels super submissive. Are you sure you can't play O5? Your other thought of O6 looks funny to me from a shape perspective too.

If :b21: is really your best move then something has gone seriously wrong. Can you at least play P5? (Not that P5 looks like a very good move either, but at least it is not playing within your own territory).

:b39: looks reasonable to me, but for :b41: I would pincer without thinking.

The :b45: - :w50: exchanges feel quite bad for Black. In particular P14 is now a complete waste of a stone.

:b51: feels right to me.

I like playing moves like :b73: and it often seems to throw my opponent off, so that's a bonus. The other thing I would consider is attaching from the side.
Author:  BlindGroup [ Sat Apr 21, 2018 5:05 pm ]
Post subject:  Re: Review Request
dfan wrote:
Welcome back!


Thanks!

dfan wrote:
:b19:: In my experience, this sort of shape (backing off with a jump in a place where you and your opponent are elbowing each other in close contact, and you are pretty strong) is never right. Whenever my opponent plays like this my eyes light up. This move in particular feels super submissive. Are you sure you can't play O5? Your other thought of O6 looks funny to me from a shape perspective too.

If :b21: is really your best move then something has gone seriously wrong. Can you at least play P5? (Not that P5 looks like a very good move either, but at least it is not playing within your own territory).


I agree. In retrospect, I think I prefer O6 or O5 for 19. I was overly concerned about losing the two white stones in the lower right. That was also the rationale for :b21:.

dfan wrote:
:b39: looks reasonable to me, but for :b41: I would pincer without thinking.

The :b45: - :w50: exchanges feel quite bad for Black. In particular P14 is now a complete waste of a stone.


I'll have to think about :b41:. The pincer does look solid, and it does avoid the resulting exchange up to :W50:. In the game, I was happy with the secure territory on top, but maybe I shouldn't have been.


dfan wrote:
:b51: feels right to me.

I like playing moves like :b73: and it often seems to throw my opponent off, so that's a bonus. The other thing I would consider is attaching from the side.


Good to know. I considered the side attachment as well, but underneath seemed to provide more options. That said, I need to spend some time with positions like this because I don't feel confident in my ability to assess the various sequences.

Thanks for your thoughts!
Author:  EdLee [ Sat Apr 21, 2018 6:41 pm ]
Post subject: 
Hi BG,

:b19: o5 hane OK. If :w20: N5 hane, just beware you cannot double hane N6 because of :white: S3.
Author:  ez4u [ Mon Apr 23, 2018 7:12 am ]
Post subject:  Re: Review Request
You cannot play a move like 79. White's profit and strength after cutting and capturing one stone are too good. For better or worse Black needs to make the hanging connection at 81, looking for a ko. However, there are not a lot of good ko threats around.

You call 89 a bad move, but I think it is too late already. In your variation White can play much more strongly. White simply plays 3 below instead of 5. Black 4 is forced and now White 5 forces 6. After White 7, however, the situation is pretty much the same as the game where Black is going to be forced into White's wall. Plus later (assuming Black somehow lives) White can break into the top using the weakness at J15.
Click Here To Show Diagram Code
[go]$$Wcm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O X . . . . . . . . . . . . . . . |
$$ | . . O X X X . . X . . . . X . . X O . |
$$ | . O O O X O X X . , . . . . . X O O . |
$$ | . X X O O O O . . . . . . . . X X O . |
$$ | . . . . . X X O X . . . . . X X O . . |
$$ | . . X . 5 X O O . . . . . . . . O . . |
$$ | . . X 6 3 1 X 7 . . . . . . . . . . . |
$$ | . . O X 4 2 . . . . . . . . . . . . . |
$$ | . O . O O . . . . , . . . . . , . . . |
$$ | . . O X . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . X X . . . |
$$ | . . . . . O O . . . . . . O . . . . . |
$$ | . O O O O X O . . , . . . O X X X . . |
$$ | . O X X O X O . . . . . . O X O O . . |
$$ | X X X X X X O . . . . . O . O X X . . |
$$ | . O . O . X . . . . . . . O . . . . . |
$$ ---------------------------------------[/go]


Of course White should have played the ko at the end, but we all make reading mistakes. :)
Before that White should have looked a little more closely at Black's potential eyes and other threats. White 104 was not necessary since Black could no longer either cut off the White corner or threaten to make two eyes. White at G8 would have been safer and White at H15 would have threatened to push into the top. White 106 at G8 would have left Black with no follow up and White 116 at B6 would again have left Black simply dead. In a sense you earned your victory by out-lasting your opponent. :tmbup:
Author:  BlindGroup [ Tue Apr 24, 2018 8:44 am ]
Post subject:  Re: Review Request
ez4u wrote:
You cannot play a move like 79. White's profit and strength after cutting and capturing one stone are too good. For better or worse Black needs to make the hanging connection at 81, looking for a ko. However, there are not a lot of good ko threats around.


Thanks for your comments! What would have been the better option/strategy for 79? After 78, the board was as follows (black to play):

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


I played A because I thought it then gave me the option of playing C in sente. But I see what you mean that white's cut at D is then too severe. I'm struggling with these kinds of situations and while I can see the problem with A, it's not at all clear to me what I should have done instead.

For me, it also raises the question of whether or not this move for black was the correct strategy at 73.
Click Here To Show Diagram Code
[go]$$c
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O X . . . . . . . . . . . . . . . |
$$ | . . O X X X . . X . . . . X . . X O . |
$$ | . . b O X O X X . , . . . . . X O O . |
$$ | . . . O O O O . . . . . . . . X X O . |
$$ | . . . . . . . . X . . . . . X X O . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . a . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . B O . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . d . . . . . . |
$$ | . . . . . . . . . . . . . . X X . . . |
$$ | . . . . c O O . . . . . . O . . . . . |
$$ | . O O O O X O . . , . . . O X X X . . |
$$ | . O X X O X O . . . . . . O X O O . . |
$$ | X X X X X X O . . . . . O . O X X . . |
$$ | . O . O . X . . . . . . . O . . . . . |
$$ +---------------------------------------+[/go]


Or maybe my initial strategy on this part of the board was off. After move 50, this was the board, and I played A with the idea of playing something like 73 once the corner sequence was done:

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


ez4u wrote:
Of course White should have played the ko at the end, but we all make reading mistakes. :)


I guess that this is not quite so obvious at my level. So, the confirmation is useful. When an opponent who is 4 stones stronger than you seems to disagree with my assessment, it seems possible that I'm not seeing the board correctly :-)

ez4u wrote:
Before that White should have looked a little more closely at Black's potential eyes and other threats. White 104 was not necessary since Black could no longer either cut off the White corner or threaten to make two eyes. White at G8 would have been safer and White at H15 would have threatened to push into the top. White 106 at G8 would have left Black with no follow up and White 116 at B6 would again have left Black simply dead. In a sense you earned your victory by out-lasting your opponent. :tmbup:


Such Pyrrhic victories are unfortunately fairly common at my level...
Author:  Joaz Banbeck [ Tue Apr 24, 2018 9:24 pm ]
Post subject:  Re: Review Request
BlindGroup wrote:
... the question of whether or not this move for black was the correct strategy at 73...

Click Here To Show Diagram Code
[go]$$Bc
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O X . . . . . . . . . . . . . . . |
$$ | . . O X X X . . X . . . . X . . X O . |
$$ | . . b O X O X X . , . . . . . X O O . |
$$ | . . . O O O O . . . . . . . . X X O . |
$$ | . . . . . . . . X . . . . . X X O . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . a . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . B O . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . d . . . . . . |
$$ | . . . . . . . . . . . . . . X X . . . |
$$ | . . . . c O O . . . . . . O . . . . . |
$$ | . O O O O X O . . , . . . O X X X . . |
$$ | . O X X O X O . . . . . . O X O O . . |
$$ | X X X X X X O . . . . . O . O X X . . |
$$ | . O . O . X . . . . . . . O . . . . . |
$$ +---------------------------------------+[/go]
...


I agree with your logic. When no good move seems available at 79, it suggests that 73 was not correct.

The attachment is way too deep. It commits you to making life in the shadow of his walls or running out of deep hole.

A better way would be the cap:

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


When he replies with likely 'a' or 'b', you attach on the opposite side with 'c' or 'd'.

BTW, 'e' is a possibility also, making miai of reductions both west and south.
Author:  ez4u [ Tue Apr 24, 2018 10:31 pm ]
Post subject:  Re: Review Request
I think the "thematic" expectation in the position below is the hanging connection at :b1: in expectation of answering :w2: with ko at :b3:. However, what will Black play as a ko threat after :w4:?
Click Here To Show Diagram Code
[go]$$Bcm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O X . . . . . . . . . . . . . . . |
$$ | . . O X X X . . X . . . . X . . X O . |
$$ | . . . O X O X X . , . . . . . X O O . |
$$ | . . . O O O O . . . . . . . . X X O . |
$$ | . . . . . . . . X . . . . . X X O . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . 1 . . . . . . . . . . . . . . . . |
$$ | . 3 4 X . . . . . . . . . . . . . . . |
$$ | . 2 X O O . . . . , . . . . . , . . . |
$$ | . . O X . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . X X . . . |
$$ | . . . . . O O . . . . . . O . . . . . |
$$ | . O O O O X O . . , . . . O X X X . . |
$$ | . O X X O X O . . . . . . O X O O . . |
$$ | X X X X X X O . . . . . O . O X X . . |
$$ | . O . O . X . . . . . . . O . . . . . |
$$ ---------------------------------------[/go]

Again theoretically speaking, if White answers :b1: above with some play on the outside, e.g. :w2:, attempting to attack on a larger scale, Black intends to hane at :b3: rather than something like simply descending. Black still invites ko but has gained a lot here since winning the new ko yields a much better position that the first diagram. Learn these ideas and add them to your repertoire!
Click Here To Show Diagram Code
[go]$$Bcm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O X . . . . . . . . . . . . . . . |
$$ | . . O X X X . . X . . . . X . . X O . |
$$ | . . . O X O X X . , . . . . . X O O . |
$$ | . . . O O O O . . . . . . . . X X O . |
$$ | . . . . . . . . X . . . . . X X O . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . 1 . . . . . . . . . . . . . . . . |
$$ | . 5 . X . 2 . . . . . . . . . . . . . |
$$ | . 4 X O O . . . . , . . . . . , . . . |
$$ | . 3 O X . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . X X . . . |
$$ | . . . . . O O . . . . . . O . . . . . |
$$ | . O O O O X O . . , . . . O X X X . . |
$$ | . O X X O X O . . . . . . O X O O . . |
$$ | X X X X X X O . . . . . O . O X X . . |
$$ | . O . O . X . . . . . . . O . . . . . |
$$ ---------------------------------------[/go]


As noted, however, a simple ko in this position is risky for Black. So what can we do instead?

One idea would be to immediately play your peep at B15. How will White answer here? If White replies at :w2: below, Black now has a ko threat at :b7:.
Click Here To Show Diagram Code
[go]$$Bcm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O X . . . . . . . . . . . . . . . |
$$ | . . O X X X . . X . . . . X . . X O . |
$$ | . 2 . O X O X X . , . . . . . X O O . |
$$ | . 1 7 O O O O . . . . . . . . X X O . |
$$ | . . . . . . . . X . . . . . X X O . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . 3 . . . . . . . . . . . . . . . . |
$$ | . 5 6 X . . . . . . . . . . . . . . . |
$$ | . 4 X O O . . . . , . . . . . , . . . |
$$ | . . O X . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . X X . . . |
$$ | . . . . . O O . . . . . . O . . . . . |
$$ | . O O O O X O . . , . . . O X X X . . |
$$ | . O X X O X O . . . . . . O X O O . . |
$$ | X X X X X X O . . . . . O . O X X . . |
$$ | . O . O . X . . . . . . . O . . . . . |
$$ ---------------------------------------[/go]

(to be continued...)
Author:  Bill Spight [ Tue Apr 24, 2018 11:10 pm ]
Post subject:  Re: Review Request
A few comments. :)

:b19: Tenuki. Both sides are strong in the bottom right. In the AI era, maybe the 3-3 in the top left corner.

:b29: Just connect. This play takes away your own liberty.

:b33: Horrid shape. Just make the hanging connection at H-17.

:b35: Loses sente, thanks to :b33: H-17 is still better.

:b37: See? :b33: and :b35: are both poorly placed.

:b39: Not a bad play, but as for double keima, I think that N-07 is better. There is more open space there, both on the right side for Black and on the bottom side for White. But to try to catch up I think maybe the attachment at C-04, which is also a probe.

:b41: One space pincer.

:b45: Maybe best to just connect at Q-17 and take sente.

:b47: Now P-14 is obviously poorly placed.

:b49: Horrid. Locally the clamp at A is better.

:b51: The attachment looks better. After :w50: the right side is small.

:b55: E-03 looks good.

:b73: Desperate measures are probably called for.
Author:  ez4u [ Fri Apr 27, 2018 6:53 am ]
Post subject:  Re: Review Request
Well Bill stold the thunder from my "to be continued" in the mean time, but I will at least add a diagram. :) Below is in regard to Black's plays from 29 through 37. Bill mentions all the problems, let's just make sure that the situation is clear.

As Bill said, 29 in the game fills Black's own liberty. Black should just play :b1: below instead. With the liberty at :b7: open, White does not threaten to cut at "a" because Black will simply play atari at "b" and capture the cutting stone. So White needs to do something about the defects in corner. Imagine White played 2 (a little weird maybe but it takes us to the game shape in the end). Now Black could split the left side before White gets there. Black could play below :w10: like in the game except there isn't a :w10: stone there yet. Instead Black plays :b3: protecting against the cut. But wait, there is no cut yet! so Black wastes a move. White exchanges :w4: for :b5: (not a good idea!) and then plays :w6: instead of :w10:. Quick! Split the left side while there is still time! No, no, don't exchange :b7: for :w8: and then waste another move at :b9:! White blocks off the corner and takes the left side as well. :o

That is what happened in the game, although the different order of moves may have hidden what was going on. Moves have consequences. Way too often we fail to see the damage that we do to ourselves. Instead we fixate on how we are able to "push around" our opponents with moves like 29 in the game or respond (at Black 33) to their moves in order to "not let them get away with things".
Click Here To Show Diagram Code
[go]$$Bcm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 6 9 . . . . . . . . . . . . . . . |
$$ | . . O X 1 X a b 3 . . . . X . . . . . |
$$ | . . . O 7 O X 5 . , . . . . . X . . . |
$$ | . . . 2 8 O 4 . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . 0 . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . X X . . . |
$$ | . . . . . . . . . . . . . O . . . . . |
$$ | . . . O . . O . . , . . . O X X X . . |
$$ | . . . . . . . . . . . . . O X O O . . |
$$ | . . . . . . . . . . . . O . O X X . . |
$$ | . . . . . . . . . . . . . O . . . . . |
$$ ---------------------------------------[/go]
Author:  Bill Spight [ Fri Apr 27, 2018 7:56 am ]
Post subject:  Re: Review Request
ez4u wrote:
Well Bill stold the thunder from my "to be continued" in the mean time, but I will at least add a diagram. :) Below is in regard to Black's plays from 29 through 37. Bill mentions all the problems, let's just make sure that the situation is clear.


Sorry, Dave. I always study your analyses. :)
Author:  BlindGroup [ Sat Apr 28, 2018 8:42 am ]
Post subject:  Re: Review Request
ez4u wrote:
As Bill said, 29 in the game fills Black's own liberty. Black should just play :b1: below instead. With the liberty at :b7: open, White does not threaten to cut at "a" because Black will simply play atari at "b" and capture the cutting stone. So White needs to do something about the defects in corner. Imagine White played 2 (a little weird maybe but it takes us to the game shape in the end). Now Black could split the left side before White gets there. Black could play below :w10: like in the game except there isn't a :w10: stone there yet. Instead Black plays :b3: protecting against the cut. But wait, there is no cut yet! so Black wastes a move. White exchanges :w4: for :b5: (not a good idea!) and then plays :w6: instead of :w10:. Quick! Split the left side while there is still time! No, no, don't exchange :b7: for :w8: and then waste another move at :b9:! White blocks off the corner and takes the left side as well. :o


Bill Spight wrote:
A few comments. :)


It took me a few days to go through these (work...), but I finally had a chance to do so this morning. Thank you both. Between the two of you, I even got answers to the questions I had about the other's comments :salute:
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