This page contains attempts and discussions that used to be on the solution page. --unkx80
Scartol: Should I leave these so that actual beginners can have a crack at them?
Okay, it looks like the best black can do is get a ko. White has to fight it; white connecting at A only leads to black life at B.
Would it work better if black goes at B?
Scartol is stupid
This was my initial response, but I realized (after I posted it -- stupid!) that white can connect after capturing the marked stone, and black is left with a dead shape once he captures the white stones.
This is the vital point I think. Once Black moves here, White can't play at 'a' because of a Black snapback, and can't play at 'b' because it's lacking a liberty. Black can form two eyes and live by playing at 1.
Black can respond with 1. Once Black moves to 1, if White tries to move to 'a', Black can capture White's stones by playing above at 'b'. If White chooses to respond at 'b' instead and capture the marked stone, Black can snapback and capture White.
If White plays at 'b' instead, Black can respond at 1, forcing White to capture at 2, then Black can play at 3. White is missing the liberty needed to capture Black. When Black plays at 3, White will have no choice but to use the move as sente. Black doesn't need to play there unless White tries to play at 'a' or 'b', in which case Black can simply capture the group of White stones.
The reason is because if , then
connects and even if Black plays at a, Black still dies in a bulky five nakade.
Now W can close ko, making B take a. If B takes over ko, he lives. In other case, W closes ko, B plays a. If then W takes c, B extends to the right, and if W doesn't play c, white can take it, close it and live
is the vital point. Variations lead to life for Black.
Kayaq: This appears to be wrong; see my example three boards down.
Here, the twisted four lives.
unkx80: Thanks to the kamikaze of , Black lives, but White could just tenuki after
and Black will still be dead with a bent three.
Kayaq: above seems not to work!
After , black cannot connect at a because of shortage of liberties.
seldon: To elaborate this further, black ataris and still fails. After the atari, white cuts at 4, black captures at 5 (or is captured in due time) and is knocked out by 1 in the second diagram.
Could somebody find an answer to kill surely blacks ?
I can't.
If W plays at a, B at b, else at a.
zinger: White plays at c. If black a in response, white connects where the marked stone was captured. Black is dead.
tonytonychopper?: how black is supposed to survive? I can't find a solution and this page only offers solutions where black dies (that i already have found by myself), but the problem asks: "how black lives?" i tried to play the position against a software too but black seems to die in all the variations....i'm getting mad...and this is exciting
unkx80: I guess there may be a problem with the way this solution is presented, as it appears that people have been missing the solution. So I rewrote the entire solution page.
tonytonychopper?: just a question: if we take in account the possibility for black of winning the ko we have to agree to the fact that IF black can win the problem becomes global and no more local, so isn't that a violation to the tsumego?
fractic: In a tsumego problem you have to find the best way to make life. In this problem the best black can get is a ko. It doesn't matter if he can win the ko or not, at least there is a chance to save the group. Even if black loses the ko he could get compensation in the form of a ko threath that white ignored. Of course if black could live withouth a ko then the ko would be a failure since black would risk his group needlessly