The king of end-game blunders

[Coyote]

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.

[HermanHiddema]

Yesterday, I resigned a game in which I was ahead

[Coyote]

Ok, you beat me there.

[SmoothOper]

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.

[HermanHiddema]

Yesterday, I resigned a game in which I was ahead

In case anyone is interested, here is the game:

https://dl.dropbox.com/u/21377571/Go/Games/2012/2012-09-09%20-%20Gelmer%20Bouwman%20-%20Herman%20Hiddema.sgf

[Alguien]

Yesterday, I resigned a game in which I was ahead

In case anyone is interested, here is the game:

Completely off topic but: Why the choice of S16?

[p2501]

Yesterday, I resigned a game in which I was ahead

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.

[HermanHiddema]

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 and 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.

[Alguien]

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 at R14? (I ask because that's what I though I had to do when I wanted sente.)

[HermanHiddema]

That's what I thought but why not 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:

$$B
$$ --------------+
$$ . . . . . . . |
$$ . . 7 6 8 . . |
$$ . 9 . X O . . |
$$ . . . X O . . |
$$ . . . . . 4 . |
$$ . . . . 1 2 . |
$$ . . . . 5 3 . |
$$ . . . . . . . |
$$ . . . . . . . |
$$ . . . , X . . |

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:

$$B tenuki
$$ --------------+
$$ . . . . . . . |
$$ . . . . . . . |
$$ . . . X O . . |
$$ . . . X O . . |
$$ . . 7 6 . 4 . |
$$ . . 8 . 1 2 . |
$$ . . . . . 3 . |
$$ . . . . a . . |
$$ . . . . . . . |
$$ . . . , B . . |

Click Here To Show Diagram Code

[go]$$B tenuki
$$ --------------+
$$ . . . . . . . |
$$ . . . . . . . |
$$ . . . X O . . |
$$ . . . X O . . |
$$ . . 7 6 . 4 . |
$$ . . 8 . 1 2 . |
$$ . . . . . 3 . |
$$ . . . . a . . |
$$ . . . . . . . |
$$ . . . , B . . |[/go]

This would be more playable if the side stone 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:

$$B at
$$ --------------+
$$ . . . . . . . |
$$ . . b a c . . |
$$ . d . X O . . |
$$ . . . X O . . |
$$ . . . 5 1 2 . |
$$ . . . 7 4 3 8 |
$$ . . . . 9 6 . |
$$ . . . . . . . |
$$ . . . . . . . |
$$ . . . , X . . |

Click Here To Show Diagram Code

[go]$$B at
$$ --------------+
$$ . . . . . . . |
$$ . . 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 and the corner will not die (though winning the ko is huge).

[Alguien]

That's what I thought but why not 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:

$$B tenuki
$$ --------------+
$$ . . . . . . . |
$$ . . . . . . . |
$$ . . . X O . . |
$$ . . . X O . . |
$$ . . 7 6 . 4 . |
$$ . . 8 . 1 2 . |
$$ . . . . . 3 . |
$$ . . . . a . . |
$$ . . . . . . . |
$$ . . . , B . . |

Click Here To Show Diagram Code

[go]$$B tenuki
$$ --------------+
$$ . . . . . . . |
$$ . . . . . . . |
$$ . . . X O . . |
$$ . . . X O . . |
$$ . . 7 6 . 4 . |
$$ . . 8 . 1 2 . |
$$ . . . . . 3 . |
$$ . . . . a . . |
$$ . . . . . . . |
$$ . . . , B . . |[/go]

Can't black forego ?

$$B
$$ --------------+
$$ . . . . . . . |
$$ . . . . . . . |
$$ . . . X O . . |
$$ . . . X O . . |
$$ . . . . . . . |
$$ . . . 5 1 2 . |
$$ . . . . 4 . . |
$$ . . 7 . . 6 . |
$$ . . . . . . . |
$$ . . . , X . . |

Click Here To Show Diagram Code

[go]$$B
$$ --------------+
$$ . . . . . . . |
$$ . . . . . . . |
$$ . . . X O . . |
$$ . . . X O . . |
$$ . . . . . . . |
$$ . . . 5 1 2 . |
$$ . . . . 4 . . |
$$ . . 7 . . 6 . |
$$ . . . . . . . |
$$ . . . , X . . |[/go]

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)

[HermanHiddema]

Can't black forego ?

$$B
$$ --------------+
$$ . . . . . . . |
$$ . . . . . . . |
$$ . . . X O . . |
$$ . . . X O . . |
$$ . . . . . . . |
$$ . . . 5 1 2 . |
$$ . . . . 4 . . |
$$ . . 7 . . 6 . |
$$ . . . . . . . |
$$ . . . , X . . |

Click Here To Show Diagram Code

[go]$$B
$$ --------------+
$$ . . . . . . . |
$$ . . . . . . . |
$$ . . . X O . . |
$$ . . . X O . . |
$$ . . . . . . . |
$$ . . . 5 1 2 . |
$$ . . . . 4 . . |
$$ . . 7 . . 6 . |
$$ . . . . . . . |
$$ . . . , X . . |[/go]

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)

and in this variation looks rather timid, and 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!

[quantumf]

Yesterday, I resigned a game in which I was ahead

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.

[danielm]

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.

[p2501]

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.