BQM 183/ Attempts

Sub-page of BQM183

Robert Pauli: Doesn't 'a' (W1 below) work without ko? Four variations (A1-A4):


A2 1-10  

A2 11-19  

A3 1-10  

A3 11-19  

A4 1-10  

A4 11-17  

Provided, B8 at 'a' can be handled. [1]

Alex Weldon: Robert's suggestion is what I played in the actual game. However, B played the following B2, which isn't accounted for in Robert's variations:

Real game 1-2  

The variations continue to be complicated from here, but a and b are miai as far as I can read. If W b, B a connects out with most of the stones. If W a, B b seems to get either a ko to escape, or a ko to live. The ko to escape was what happened in the actual game, as follows (well, except for a couple of bad internal pseudo-sente moves after W7 with which B gave W a chance to kill by playing at B8, but W answered):

Real game 3-12  

Robert Pauli: OK, Alex, let's try A5 and A6:

A5 1-10  

A5 11-20  

A5 21-30  

A6 1-10  

A6 11-19  

Robert Pauli: If White defends against the peep B8 in A6, Black plays 'k' for a second eye by ko. Could Black profit from peeping earlier? Seems no:

A7 1-10  

A7 11-20  

Alex Weldon: I cannot find any move for B that causes Robert's solution to fail. I say let's give it a week or so to let all the other dan players have a poke at it and see if it holds up, and if so, we'll call it solved. This would make an excellent Tsumego From Games, I think. The solution is really tough. If this works, kudos to Robert!

Robert Pauli: Tough indeed - certainly for me. Guess we'll never be sure if Black can't pull something. BTW, what about the rest of the board ?

Alex Weldon: The (commented) record of the entire game is at [ext]

Robert Pauli: Thanks a lot, Alex!

Robert Pauli: Just took a look at the (afterwards given) game. Very nicely commented, Alex!

For reference, the complete [ext] position is this one:

Move 139  

The question was if Black's center can be captured? I opted for a and, as it turned out, Alex did just that.

But due to the marked black stones my solution A4 fails ([1]) . So, this seems to be what Black (just 8-kyu ??) should have done.

Anyway, the game went one to this:

Move 158  

Now White took the ko, ignored the threat at a, and connected.

White came in quite a mess after Black continued at 3-3 in the upper left corner and White, unwilling to let go his two stones above a, allowed him to live . . .

Back to W1 above, couldn't White simply have skipped the ko by connecting at b instead? The marked white stone seems to escape -- either connecting with the center, the bottom left, or the bottom right -- and the capturing race in the center shouldn't be a problem either, even after a cut starting with c.

BQM 183/ Attempts last edited by MrTenuki on July 9, 2006 - 02:11
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