Flipping through my past issues of Weiqi Tiandi ("Go World" in China, unrelated to the American one), I noticed the following tsumego problem (2006.15). It says that if you can solve it within 10 minutes, your fundamental skills have reached the pro level. That gave me a chuckle or two, because it took me only a few seconds to arrive at the solution. (Hohoho, I am a pro )
Seriously, I think the editor way over-estimated the difficult level of the problem. Give it a try and let me know what you think.
This one seems to be a ko. Better, but unfortunately I'm taking a quick break from work... so since I didn't see it the first two times, I'm saying it's ko.
Author:
hiyayang [ Sun Jan 02, 2011 12:02 pm ]
Post subject:
Re: A "Pro-Level" Tsumego
Here is my take on the bonus questions:
I suspect the first move is the same in all three questions: B3 is the vital point for both black and white.
but I am not sure whether it is the best. A similar shape is given in the section on Carpenter's Squares in Segoe Kensaku's Tsumego Dictionary (http://senseis.xmp.net/?SegoeTsumegoDictionary), where black kills the white corner. The key difference between the two shapes is that the white group here has quite a few outside liberties.
Point wise, the seki is no better (and possibily even worse, because of white's endgame move at 'a') for black than simply letting white live like this:
In standard carpenter's square, white's correct response to is in the diagram below, which might as well be the best defense for white here, if a ko fight is unfavorable to white.
[go]$$Bc best defense? $$ --------------------------------------- $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . . . . . . . . . . . | $$ | . . . . . X . . . . . . . . . . . . . | $$ | . X X X . . . X . . . . . . . . . . . | $$ | a O X O . O . . . . . . . . . . . . . | $$ | . . O O . O X . . , . . . . . , . . . | $$ | . b . O X X . X . . . . . . . . . . . | $$ | . 1 c O X . . . . . . . . . . . . . . | $$ | . 2 . d . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]
Black's next move can be a, b, c or d, but in each case it appears that the result would be seki or ten-thousand year ko.
Author:
usagi [ Sun Jan 02, 2011 9:18 pm ]
Post subject:
Re: A "Pro-Level" Tsumego
hiyayang wrote:
Flipping through my past issues of Weiqi Tiandi ("Go World" in China, unrelated to the American one), I noticed the following tsumego problem (2006.15). It says that if you can solve it within 10 minutes, your fundamental skills have reached the pro level. That gave me a chuckle or two, because it took me only a few seconds to arrive at the solution. (Hohoho, I am a pro )
Seriously, I think the editor way over-estimated the difficult level of the problem. Give it a try and let me know what you think.
Hello!
Back when Willzhang was teaching on KGS, I was his student, and he presented this problem to me. I, too, thought I found the solution in about 5-10 minutes. Then a few hours later, I thought I found the solution again. Then a day later. Eventually I gave up - he never told me the solution. I hope you have an answer book on hand because it's likely not what you think
Author:
CSamurai [ Sun Jan 02, 2011 11:45 pm ]
Post subject:
Re: A "Pro-Level" Tsumego
usagi wrote:
hiyayang wrote:
Flipping through my past issues of Weiqi Tiandi ("Go World" in China, unrelated to the American one), I noticed the following tsumego problem (2006.15). It says that if you can solve it within 10 minutes, your fundamental skills have reached the pro level. That gave me a chuckle or two, because it took me only a few seconds to arrive at the solution. (Hohoho, I am a pro )
Seriously, I think the editor way over-estimated the difficult level of the problem. Give it a try and let me know what you think.
Hello!
Back when Willzhang was teaching on KGS, I was his student, and he presented this problem to me. I, too, thought I found the solution in about 5-10 minutes. Then a few hours later, I thought I found the solution again. Then a day later. Eventually I gave up - he never told me the solution. I hope you have an answer book on hand because it's likely not what you think
If you read carefully, you'll find that the poster has already shared the solution found in the article which he found the problem in.
White group has enough outside liberties to kill the black inside, even though the latter has an eye. Note that black at doesn't connect. (If black plays instead of , white plays and the result would be the same as the diagram below.)
Other black moves like the below would also allow white to live:
When white corner lacks outside liberties (e.g., the 'a' spots are taken by black), below is another way to kill white corner, but it doesn't work in this case (because doesn't put itself in atari):
)
do better?
do better?
seems the strongest resistance by black -- If white got this spot (and a solid eye at C3), it seems so easy for white to live.
, 'a' and 'b' are miai for white to live.
before 
in this diagram:
and 
.
, here is a diagram to show it is dead:
at 
doesn't connect. (If black plays