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The king of end-game blunders
http://www.lifein19x19.com/viewtopic.php?f=10&t=6711
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Author:  Coyote [ Mon Sep 10, 2012 8:21 am ]
Post subject:  The king of end-game blunders

Last night I played a closely fought game in the Canadian Go Internet League's Handicap division. I thought I was ahead but things were closer than I though. In much of the end game I was pushing my opponent around because I was reading better than him and playing moves that threatened two things and he kept choosing to save the smaller ones.

Right at the end I closely read a corner enclosure that although there was no way I could play within and live, it looked suspiciously short of liberties and I tried to read if I could kill it. I decided I couldn't and passed, ending the game.

then my opponent played another move closing a tiny gap in his territory that wasn't a major threat to him. I didn't even need to respond, so I passed.

My opponent passed and won by .5

Ah! If I had played there instead of passing my opponent would have easily defended but lost a point, and the game.

Sometimes it's not about making a big kill.

Anyway, wanted to share. I find it hilarious because it was such a simple obvious move that cost me the game, but not because I let a big group die that I could have saved.

Author:  HermanHiddema [ Mon Sep 10, 2012 8:36 am ]
Post subject:  Re: The king of end-game blunders

Yesterday, I resigned a game in which I was ahead :blackeye:

Author:  Coyote [ Mon Sep 10, 2012 9:05 am ]
Post subject:  Re: The king of end-game blunders

Ok, you beat me there.

Author:  SmoothOper [ Mon Sep 10, 2012 9:33 am ]
Post subject:  Re: The king of end-game blunders

The other day on IGS I left a ko on the board after passing and lost by .5, I couldn't figure out how to resume play to take it either, if that is even possible.

Now I make sure to fill in a few dame especially ones that remove ko threats before passing.

Author:  HermanHiddema [ Wed Sep 12, 2012 1:17 am ]
Post subject:  Re: The king of end-game blunders

HermanHiddema wrote:
Yesterday, I resigned a game in which I was ahead :blackeye:


In case anyone is interested, here is the game:


Author:  Alguien [ Wed Sep 12, 2012 1:35 am ]
Post subject:  Re: The king of end-game blunders

HermanHiddema wrote:
HermanHiddema wrote:
Yesterday, I resigned a game in which I was ahead :blackeye:


In case anyone is interested, here is the game:


Completely off topic but: Why the choice of S16?

Author:  p2501 [ Wed Sep 12, 2012 1:50 am ]
Post subject:  Re: The king of end-game blunders

Alguien wrote:
HermanHiddema wrote:
HermanHiddema wrote:
Yesterday, I resigned a game in which I was ahead :blackeye:


In case anyone is interested, here is the game:


Completely off topic but: Why the choice of S16?

Which is Black 33 in the game.

Author:  HermanHiddema [ Wed Sep 12, 2012 1:58 am ]
Post subject:  Re: The king of end-game blunders

Alguien wrote:
Completely off topic but: Why the choice of S16?


Because I would like to end in sente to play first in the upper left. The game variation is what I expected, and :b47: and :b49: are the moves I wanted to play first. The game variation is, locally, much better for white than the usual variation where black extends, but the white ends in sente. I felt that the stone at R6 had sufficient aji to warrant playing like this.

Author:  Alguien [ Wed Sep 12, 2012 2:07 am ]
Post subject:  Re: The king of end-game blunders

HermanHiddema wrote:
Alguien wrote:
Completely off topic but: Why the choice of S16?


Because I would like to end in sente to play first in the upper left.


That's what I thought but why not :b31: at R14? (I ask because that's what I though I had to do when I wanted sente.)

Author:  HermanHiddema [ Wed Sep 12, 2012 2:32 am ]
Post subject:  Re: The king of end-game blunders

Alguien wrote:
That's what I thought but why not :b31: at R14? (I ask because that's what I though I had to do when I wanted sente.)


R14 is possible, but does not necessarily end in sente.

R14 S14 S13 S15 R13 would be usual, then Q18 P18 R18 O17 and white has sente:

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


To get sente, black would have to forego a move like R13, but then his position is very thin:

Click Here To Show Diagram Code
[go]$$B :b5: tenuki
$$ --------------+
$$ . . . . . . . |
$$ . . . . . . . |
$$ . . . X O . . |
$$ . . . X O . . |
$$ . . 7 6 . 4 . |
$$ . . 8 . 1 2 . |
$$ . . . . . 3 . |
$$ . . . . a . . |
$$ . . . . . . . |
$$ . . . , B . . |[/go]


This would be more playable if the side stone :bc: were at a.

Another usual option to get sente would be the double hane, R15 S15 S14, then after the cut and capture R14 Q15 S13 atari on top with Q14:

Click Here To Show Diagram Code
[go]$$B :w10: at :b3:
$$ --------------+
$$ . . . . . . . |
$$ . . b a c . . |
$$ . d . X O . . |
$$ . . . X O . . |
$$ . . . 5 1 2 . |
$$ . . . 7 4 3 8 |
$$ . . . . 9 6 . |
$$ . . . . . . . |
$$ . . . . . . . |
$$ . . . , X . . |[/go]


But I don't really like this variation. White's position is strong, and since white has not exchanged a-b-c-d, there is much more scope for invasion in the top. Alternatively, white can tenuki with :w10: and the corner will not die (though winning the ko is huge).

Author:  Alguien [ Wed Sep 12, 2012 2:51 am ]
Post subject:  Re: The king of end-game blunders

HermanHiddema wrote:
Alguien wrote:
That's what I thought but why not :b31: at R14? (I ask because that's what I though I had to do when I wanted sente.)


R14 is possible, but does not necessarily end in sente.

To get sente, black would have to forego a move like R13, but then his position is very thin:

Click Here To Show Diagram Code
[go]$$B :b5: tenuki
$$ --------------+
$$ . . . . . . . |
$$ . . . . . . . |
$$ . . . X O . . |
$$ . . . X O . . |
$$ . . 7 6 . 4 . |
$$ . . 8 . 1 2 . |
$$ . . . . . 3 . |
$$ . . . . a . . |
$$ . . . . . . . |
$$ . . . , B . . |[/go]



Can't black forego :b3: ?

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

:b3: tenuki

(I'll accept as answer "that's awful for b" or "w wouldn't play that". Also, I'm very sorry for the massive thread derailment)

Author:  HermanHiddema [ Wed Sep 12, 2012 3:05 am ]
Post subject:  Re: The king of end-game blunders

Alguien wrote:
Can't black forego :b3: ?

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

:b3: tenuki

(I'll accept as answer "that's awful for b" or "w wouldn't play that". Also, I'm very sorry for the massive thread derailment)


:w4: and :w6: in this variation looks rather timid, :b5: and :b7: are excellent moves for black, and after this variation, black may have a huge top moyo. If black used his tenuki in the same way as in the game, then I'd expect white to invade the top immediately, and black's position here is too thin, IMO, for him to welcome that fight.

Also, these are valid questions relevant to the thread, so don't feel bad for posting them! :)

Author:  quantumf [ Wed Sep 12, 2012 3:57 am ]
Post subject:  Re: The king of end-game blunders

HermanHiddema wrote:
Yesterday, I resigned a game in which I was ahead :blackeye:


Is the lead that clear? Seems like there is a LOT of complex endgame still to resolve, with lots of hard to defend borders still in place.

Author:  danielm [ Wed Sep 12, 2012 4:17 am ]
Post subject:  Re: The king of end-game blunders

What about forgetting a captured stone in my lid after scoring, in a game that I lost by 0.5 points? This happened during my first (and only so far) over-the-board tournament, and it would have been severely disappointing had it not been so hilarious.

Author:  p2501 [ Wed Sep 12, 2012 4:26 am ]
Post subject:  Re: The king of end-game blunders

I counted a finished game in a tournament wrong by as much as 3 points and declared my loss. Only to be informed by others that I counted wrong and win by half a point.

In another tournament I passed while beeing ahead by roughly 40+ points. I lost by resignation for being cocky and not responding to my opponents last move due to a misread.

Author:  HermanHiddema [ Wed Sep 12, 2012 5:24 am ]
Post subject:  Re: The king of end-game blunders

quantumf wrote:
HermanHiddema wrote:
Yesterday, I resigned a game in which I was ahead :blackeye:


Is the lead that clear? Seems like there is a LOT of complex endgame still to resolve, with lots of hard to defend borders still in place.


IMO, yes it is. Black is ahead by 5-10 points and has sente. There is a lot of endgame remaining, but it is all fairly straightforward. I don't see the kind of swing happening that white needs to win.

Author:  Dusk Eagle [ Wed Sep 12, 2012 6:03 am ]
Post subject:  Re: The king of end-game blunders

Herman, I'm still not convinced about the sequence in the upper-right corner. Yes, you make your top side stronger with such a sequence, but you also make white's S4 group significantly stronger as well. If I were playing in your shoes and wanted sente, I would prefer the double hane sente variation, as it doesn't hurt your R10 stone as much. I'm weaker than you but I just thought I would put this out there and see if you had any comment on in.

P.S. All of the diagrams you posted are one line shorter than they should be, so the R10 stone is actually one line farther away than what you showed.

Author:  HermanHiddema [ Wed Sep 12, 2012 6:22 am ]
Post subject:  Re: The king of end-game blunders

Dusk Eagle wrote:
Herman, I'm still not convinced about the sequence in the upper-right corner. Yes, you make your top side stronger with such a sequence, but you also make white's S4 group significantly stronger as well. If I were playing in your shoes and wanted sente, I would prefer the double hane sente variation, as it doesn't hurt your R10 stone as much. I'm weaker than you but I just thought I would put this out there and see if you had any comment on in.

P.S. All of the diagrams you posted are one line shorter than they should be, so the R10 stone is actually one line farther away than what you showed.


Just because I'm stronger doesn't mean I'm right :)

I think the double hane variation is a viable alternative. It may well be better. I just have a sort of personal prejudice against it ;)

The variation I played makes a really strong black group. Extra strong because of the way the corner player out with R18 and S18. Perhaps it is overconcentrated, but it makes invasion completely unrealistic after F15, IMO.

Certainly my opponent completely mishandled the right side later. After :b89: (T5), it is an unmitigated disaster.


Fixed the diagrams, thanks!

Author:  Alguien [ Wed Sep 12, 2012 6:41 am ]
Post subject:  Re: The king of end-game blunders

I hereby display my move 224 as a classic example of the "lose my game in the last move" style.

I must say in my defense that I'm pretty sure I played that move after some pints of beer (DGS + phone app).


Author:  kivi [ Wed Sep 12, 2012 10:35 am ]
Post subject:  Re: The king of end-game blunders

HermanHiddema wrote:
HermanHiddema wrote:
Yesterday, I resigned a game in which I was ahead :blackeye:


In case anyone is interested, here is the game:

White 186 is self-atari for the huge group, and stays ready to be captured until move 196.

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