BQM 262

From Cho Hun-hyeon Weiqi Sucheng. Either the book is wrong or I am seriously misunderstanding an aspect of this problem. Please review and correct.

Volume 3, Problem 23

Problem Diagram  

Book Answer  

White Alternative  

After , the marked white group () wins the capturing race with the marked black group (), thereby saving the stones. Black does have a ladder against the two stones. Are ladders assumed to be good for Black in problems of this type?

Bill: Yes, as I understand it. That follows from the assumption that all relevant stones are shown. If there is a ladder breaker, it should be shown. If one isn't shown, it's not there.

unkx80: Yes. Unless stated otherwise, Chinese books assume that the remainder of the board is empty, and hence all ladders are good for either player. I presume Japanese books make the same assumption as well. In fact, the Igo Hatsuyoron seems to take this idea a bit far, in that quite often crawling along the second line is also considered a solution for making life.

Thank you both. Yes, all the stones are shown. The book diagram only a quarter of the board.

No ladder required?  

dnerra: Doesn't this do everything we want without requiring a ladder?

No ladder required?  

unkx80: I wanted to post something about this too. However, I was not able to read out completely what happens here. at may be another possible variation.