Go life and death 2

  
Problem

Go: life and death (2)


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Lionel Vidal    (2006-11-15 14:39:26)
Go: life and death (2)

Still not too difficult, but not so easy either. This problem from Yang Yilun is called 'Small Land'.
White to play and live inside Black's walls!
GoPosition (see diagram)
19
18
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2
1
   a b c d e f g h j k l m n o p q r s t




Thibault de Vassal    (2006-11-15 16:30:46)
Instinct only ?

Impossible to calculate all ways in my mind :)

I suppose strong players instantly know where to play the first stone, so I predict...... something like Wt19 or Wr16. No, finally Wt19 seems quite bad... Or maybe Wq18 ?

Still not ?

Okay, I choose Wr17 :))


Lionel Vidal    (2006-11-15 18:10:28)
The first move is unique!

Well, here is an hint: there is only one first move to make life, and you did not mention it :-)


Thibault de Vassal    (2006-11-22 21:40:03)
Small land

Ok... I was thinking about Ws19 or Wt18 but there is more space around q18-q19 (Black stones are farther), what about Wt18 ? .. with then two possibilites Wt16 or Wq18.


Lionel Vidal    (2006-11-22 21:58:37)
Nope, try again!

Here is a hint: Wq18 fails because of Br16 Wr17 Bt17 Wt18 Br19 and white dies.
Now you can see why Wt18 fails also in the same way.
You have to fully use the available space for making eyes... the last move Br19 in my last variation may help you to find the key!


Thibault de Vassal    (2006-11-22 22:24:01)
q19

... why didn't I envisage Wq19 ??

Looks quite natural :)


Lionel Vidal    (2006-11-23 17:32:40)
You found the key, but...

Ok, you found the key! Wq19 is the only way to live!
But... what do you play after Br16?


Thibault de Vassal    (2006-11-24 00:57:47)
Suite

Wq19,Br16,Ws19 .. now q17 and s16 stones really help to build the small land !?


Lionel Vidal    (2006-11-24 18:41:41)
Ok you got it!

After Wq19 Br16, the trap is Wq17, and white dies after the nice sequence Bt17 Wt18 Bs19 Wr19 Bq18 Wp18 Bp19.
So the solution is Wq19 Br16 Ws19 and White ensures 2 eyes!
I quite like the calmness of the two white moves in this frigthening environment!


Grindel Redmage    (2006-11-29 15:09:27)
q19

this is also pretty simple