Shape Problem 6 / Discussion

Sub-page of ShapeProblem6
White to make shape (i)  

Charles So I see this ladder ...

White to make shape (ii)  

... and if the ladder (actually, either one of parallel ladders) is good for White, White might have no problems here. The net might be a strange ko.[1]

White to make shape (iii)  

Backtrack to here, which is the first chance for White to vary.

White to make shape (iv)  

W1 looks good because the capture now for Black causes shortage of liberties. But if Black answers by extending from black+circle, it's a serious ko.


unkx80: Takes some reading to see this. B6 is neccessary to prevent a. After this, White can play elsewhere.

Charles Yes, I thought of W1 just after I went out shopping.

HolIgor: When I set this problem I has this solution in mind. The discussion that followed was interesting, so I will wait for the final words before making the solution page.

Bill: I think that on an empty board (except for the ladder breaker) I would like this variation, keeping sente. I also think that the choice among this variation, the first net variation, and the second net variation depends upon the rest of the board.

HolIgor: Wow, quite a heavyweight discussion.

I played the variation leading to ko and consider it wrong. Yet, for the benefit of beginners I will explain what I wanted to achieve.

What White had in mind  

After clearing up the captured stones

Shortage of liberties  

Black cannot connect because of the shortage of liberties and has to play B1. White capture and black takes firm grip of two white stones.

The result  

The final white's shape is excellent. It is thick, the eyes are almost there and white kept sente.

HolIgor: What happened in the game was, however a ko

What white had in mind  

Black extended with B2 and after W3 captured with B4. White had to play elsewhere and black filled the ko producing the following position

The result in the actual game  

This was not too bad for White either because there is a great piece of advice that ugly shapes have to be sacrificed; and the shape of the white+circle stones is ugly.


Charles Actually, I think we're not yet done with this very interesting question: see Shape Problem 6/Net variation.


Another net  

Bill: As long as we're willing to sacrifice the ugly stones, this doesn't look so bad.

Charles Indeed. But gote.

Shape Problem 6 / Discussion last edited by BillSpight on June 25, 2004 - 15:57
RecentChanges · StartingPoints · About
Edit page ·Search · Related · Page info · Latest diff
[Welcome to Sensei's Library!]
Search position
Page history
Latest page diff
Partner sites:
Go Teaching Ladder
Login / Prefs
Sensei's Library