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JBSSolution
Post your solution here. HolIgor: I won't post a solution yet. In fact I am amazed with the level of this problem. Could it be dan level? We have not heard from our dans yet. I have lost it in an IGS game. I agreed gladly to this position considering it a sure win for black. But it proved to be much more difficult than expected. So, I decided that black lose here. - Perhaps I should have added I'm a European 2dan. Goran When I opened a book at random diagram I could not believe my eyes. Is it possible for black to win? Some general words about the solution. The motives are usual: a group with an eye wins agains a group without eyes, hence some eye stealing, a sacrifice to gain tempo, damezumari, of course. But everything requires exact reading.
HolIgor: Black can do better.
I'm not sure of the best 'defence' for white, but I cannot see any quick ways for white to save his stones after B1. ..?
Oops. I thought black could cut one to the left of 6, but he cannot.:-( DaveSigaty: I couldn't figure this one out. Finally I gave up and searched my books for an analysis - I wasn't even close to finding the key play (which is B's second play rather than his first!). The honor of posting the answer belongs to HolIgor when he is ready.
Before HolIgor does so, allow me to make a try... After black 7, white clearly is one move behind.
A better defense for white seems white 2 here. After white 12, black loses despite the MeAriMeNashi.
Black however has an improvement with black 7 here. First destroying the eye, then moving out seems to be enough to save black.
Playing white 6 on this side does not work either. After black 7, the best white can get is to capture black 5 in sente.
One more line of defense seems open for white, namely white 4 here. But the black 5- white 6 exchange again saves the day. If white plays white 6 at 'a', black plays at 6, and grabs liberties again. -- AndreEngels
I hate disagreeing with stronger players, but how does black play after white 6 here? Black must defend against white 'a'. Black at 'b' gives white 'd' and black dies. Black at 'a' gives white 'c' and black dies. Black at 'e' again gives white 'c' and black suffers? -- MortenPahle You should not hate disagreeing with me. Certainly not when, like in this case, you are right and I am wrong. -- AndreEngels HolIgor: The move proposed by Morten is a strong defence but Cho shows how to beat it. Consider it a new problem.
Yes, black sacrifices two stones but kills the rest. --HolIgor Thus the first move is found:
White's strongest defence is 2. So the problem is to find black's second move which is the key as Dave put it. -- HolIgor
Yes, this is the solution. The variations should be considered yet.
dnerra: I just looked at this problem and read out this simple-minded sequence. It looks so obvious that it might be worth discussing: What did I miss in this sequence?
Apparently, W1 in this diagram is the only move here. (W a, B b, W 1, B c should usually be very good for black, as white has to come back and make life at 'd'.
Usual tesuji in such cases is this white 1. I give only one variation. But one has to be very careful. The problem is very good. It was published more than a half millenium ago. This is a copy of the living page "JBSSolution" at Sensei's Library. (C) the Authors, published under the OpenContent License V1.0. |