Semeai

Bill Spight · Post by **Bill Spight** » Wed May 04, 2011 12:14 pm

Click Here To Show Diagram Code: [go]$$Bc Black to play $$ ---------------------- $$ | . O . O . . . O . . . $$ | X X O X X X X O X . . $$ | . X O O X . . . O O . $$ | O O O O X . O . X O . $$ | O X X O X O X . X O . $$ | . . X . X O . . . . . $$ | . X . X X O . . . . . $$ | . O O O X O . . . . . $$ | . . . . O O . . . . . $$ | . . . O . . . . . , . $$ | . . . . . . . . . . .[/go]

A little test of reading skill.

Enjoy!

[admin]
Added numbers. Hope nobody minds. -JB
[/admin]

John Fairbairn · Post by **John Fairbairn** » Wed May 04, 2011 12:22 pm

The famous Go Seigen-Fujisawa catastrophe! Now that's what I call not dumbing down

HermanHiddema · Post by **HermanHiddema** » Thu May 05, 2011 2:09 am

The obvious approach seems to be

below...

Click Here To Show Diagram Code: [go]$$B :w8: @ :wc:, :b9: @ :w4:, :w10: @ :b7: $$ ---------------------- $$ | . O 7 W 4 5 . O . . . $$ | X X O X X X X O X . . $$ | . X O O X . . . O O . $$ | O O O O X . O . X O . $$ | O X X O X O X . X O . $$ | 1 . X 3 X O . . . . . $$ | . X 2 X X O . . . . . $$ | 6 O O O X O . . . . . $$ | . . . . O O . . . . . $$ | . . . O . . . . . , . $$ | . . . . . . . . . . .[/go]

Now black is losing the semeai

Click Here To Show Diagram Code: [go]$$Bm11 :b13:, :b17:, :b19: @ the :bc: marked points, :w20: @ :b11: $$ ---------------------- $$ | 2 O O O X X 8 O . . . $$ | B B O X X X X O X . . $$ | 1 B O O X . 6 . O O . $$ | O O O O X . O . X O . $$ | O X X O X O X . X O . $$ | X 5 X X X O . . . . . $$ | 4 X O X X O . . . . . $$ | O O O O X O . . . . . $$ | . . . . O O . . . . . $$ | . . . O . . . . . , . $$ | . . . . . . . . . . .[/go]

After white captures, he is ahead by one liberty

The alternative is to play

like this:

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

White connects under with

, then with

and

prevents black from making two eyes, allowing black to connect out, sealing him in again with

Now, unless black has some serious support on the outside, he seems dead to me.

aurik · Post by **aurik** » Thu May 05, 2011 9:21 am

HermanHiddema wrote:
The obvious approach seems to be below...
<snip>

I got

as well, but a different sequence to give black at least a ko for life. Not capturing at 6 seems to be the key.

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

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

9 @ 1, now W has 2 libs and B has 3. So W cannot play this way.

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

Click Here To Show Diagram Code: [go]$$B Seki is wishful thinking though, this reverts to ko. $$ ---------------------- $$ | O O 7 W O X . O . . . $$ | 2 1 O X X X X O X . . $$ | . 5 O O X . 3 6 O O . $$ | O O O O X 4 O . X O . $$ | O X X O X O X . X O . $$ | X . X X X O . . . . . $$ | . X O X X O . . . . . $$ | O O O O X O . . . . . $$ | . . . . O O . . . . . $$ | . . . O . . . . . , . $$ | . . . . . . . . . . .[/go]

Click Here To Show Diagram Code: [go]$$B :w6: at circled stone, B makes ko by playing atari from the outside. $$ ---------------------- $$ | O O 5 W O X . O . . . $$ | 2 1 O X X X X O X . . $$ | . 3 O O X . 4 . O O . $$ | O O O O X . O . X O . $$ | O X X O X O X . X O . $$ | X . X X X O . . . . . $$ | . X O X X O . . . . . $$ | O O O O X O . . . . . $$ | . . . . O O . . . . . $$ | . . . O . . . . . , . $$ | . . . . . . . . . . .[/go]

It feels like one should be able to exploit the weakness at h17, though. Maybe it can be used to eliminate ko entirely?

gonut · Post by **gonut** » Fri May 06, 2011 4:16 pm

One move seems to make Black miai of living and creating an extra outside liberty for the corner semeai.

Because I'm probably incorrect (such is the life of a weak kyu player), I've only included a couple sequences to show the idea.

In any event, thanks for yet another nice problem, Bill!

Post by **Joaz Banbeck** » Fri May 06, 2011 10:11 pm

aurik · Post by **aurik** » Fri May 06, 2011 11:18 pm

gonut · Post by **gonut** » Sat May 07, 2011 8:57 pm

Aurik, your refutation is correct! I missed that Black's outside stones would have a shortage of liberties. Ugh.

Anyway, I'll try once more to show what solution theme Bill probably had in mind, and then I'll go hide in a cave.

Koroviev · Post by **Koroviev** » Mon May 09, 2011 5:13 am

John Fairbairn wrote:The famous Go Seigen-Fujisawa catastrophe! Now that's what I call not dumbing down

What does this mean?

John Fairbairn · Post by **John Fairbairn** » Mon May 09, 2011 12:16 pm

What does this mean?

Even leaving metaphysics out of it, I'm not sure what you mean. Is is the reference you don't get, or is "dumbing down" too colloquial for a foreigner?

The reference is that the position comes (with a slight cosmetic change) from Game 1 of the 1951 ten-game match between Go and Fujisawa, and both players - the first 9-dans in history - famously made a mess of getting to this position. The scorekeeper pointed out they had both missed a tesuji. Even in this position, there are extreme difficulties for many amateurs involving a ko and a yoseko. Hence the presenter of this problem is not "dumbing down", i.e. is not offering something for a low level of player.

The full story is in my "9-dan Showdown".

Koroviev · Post by **Koroviev** » Mon May 09, 2011 1:56 pm

John Fairbairn wrote:
What does this mean?
Even leaving metaphysics out of it, I'm not sure what you mean. Is is the reference you don't get, or is "dumbing down" too colloquial for a foreigner?

The reference is that the position comes (with a slight cosmetic change) from Game 1 of the 1951 ten-game match between Go and Fujisawa, and both players - the first 9-dans in history - famously made a mess of getting to this position. The scorekeeper pointed out they had both missed a tesuji. Even in this position, there are extreme difficulties for many amateurs involving a ko and a yoseko. Hence the presenter of this problem is not "dumbing down", i.e. is not offering something for a low level of player.

The full story is in my "9-dan Showdown".

What I mean is: "what do you mean?" if you see what I mean.

The reference was what I was after - I'm not a foreigner by the way, just a fan of Russian literature.

Story sounds fascinating, 9-dan Showdown is now on my 'to buy' list.

emeraldemon · Post by **emeraldemon** » Thu Nov 01, 2018 8:57 am

Koroviev wrote: The reference was what I was after - I'm not a foreigner by the way, just a fan of Russian literature.

I don't know what exactly JF would consider a foreigner, but he disapproves using "cookie" for "biscuit"...

jlt · Post by **jlt** » Thu Nov 01, 2018 10:02 am

The solution to the semeai problem also appears in Abe Yoshiteru's book "Dramatic Moments On the Go Board".

Bill Spight · Post by **Bill Spight** » Thu Nov 01, 2018 12:10 pm

I had forgotten about this topic. I should have given a solution.

However, not long after posting this (Edit: in 2011) I underwent an operation for cancer, and not long after that, my wife's (then girlfriend's) brother died suddenly. Not an easy time.

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