A Kiseido publishing book by Richard Bozulich, volume 2 in the Mastering the Basics series.
The book is divided into the following sections:
1 move problems:
200 problems: Black to live
200 problems: Black to kill
3 move problems:
200 probems: Black to live
100 problems: Black to kill
5 move problems:
100 problems: Black to live
201 problems: Black to kill
Each problem (tsumego) in the book gets only one solution diagram. The introduction states that it is up to the reader to verify that the solution presented is the best solution to each problem.
See also:
Dieter: I'm a fond lover of tsumego, and thus this book with 1001 problems is a sweet treasure. The level of the first move problems is rather low: I (1 Dan) did a bit more than one hour over the first 140 problems in two intervals - waiting in a queue, so not really trying to break my record. So it's fair to say that they take me less than 20 seconds to solve, subtracting the time used for flipping pages and verifying the answers. I got three wrong out of 140. I like this: it is fast food for the brain.
I do have one severe criticism of the book. The solution diagrams are accompanied by two lines of comments that are mere variations on the theme "After Black 1, there is no way for White to kill". Only very occasionally avoiding ko is mentioned and exceptionally a wrong first move is indicated. I have nothing against solution diagrams without comments: I rely on the knowledge of the Nihon Ki-in (in this case). But if the writers do add comments, they should be worthwhile.
Stefan: Not to imply that your criticism isn't valid, but to be fair to the author he does warn the reader in the Preface. In order to include so many problems in a limited number of pages, the explanations are minimal. The reader should make the effort to verify that the answer to each problem is indeed the best and most profitable and to prove to himself that any other move fails to achieve the stated objective. This effort is also part of the practice that these problems provide. And about the 'avoiding ko' point: in all problems, Black must either live unconditionally or kill White unconditionally. That is, an answer that leads to a ko is a failure unless Black can live or kill by creating a double ko.
Velobici: The level of the first move problems must be below 1 Dan... I can solve them and I am no 1 Dan. I would estimate them as being 10 kyu to 5 kyu. The last 200 problems, Five moves problems, Black to kill, are considerably more difficult than the first 801. This fits in with Kato Masao's statement in Attack and Kill that killing is considerably harder than living.
Tderz: I agree with Dieter's comment's on the shortness of the comments. Even if the introduction might warn about the shortness, the numerous After Black connects/captures/etc. at 1 his stones are alive. are simply superflous when the problem titles indicated already Black to live, resp. Black to kill. The space could have been better used to comment on a wrong path instead.
I got this problem book as a wrong delivery instead of 501 Opening Problems. While I (3dan) didn't buy it in the shop, because I thought the problems were too easy, I liked it very much in the end when I went through all problems. Not for nothing the Kansai Kiin's professional advice is Do study tsume go, everyday and also repeat many easy problems very often. At the end I was astonished to have made many (small and grave) errors. I also count as wrong, if my first move is correct, but I did not see white's strongest response. In a real game it might still work out, but it indicates a lack. Also I discovered many of those small errors of the book itself.
While going through all of the problems (In 6 weeks, because I'm a busy father of two) I realized that an index is missing as in the 'Igo Hatsuyoron', so I made one for myself. Being critical about my own errors, underlining slight errors once (living too small) and giving up during a problem and failures twice. It's revealing to discover blind spots, like having only 4 options for a move and the correct one is first a connecting move.
First I was convinced that there are several doubles in the book, but there are just many similar positions and it's very teaching why their respective solutions are dis-similar. Altogether I am very happy that I went through the book and can only recommend it very much (cf. Kansai Kiin's advice).
Richard Hunter: This book is virtually 100% based on New Igo bessatsu #28. I was the one who recommended it to Richard, having read the Japanese book twice and loved it. In the Japanese book, the first 400 problems have no comments, only a single word naming the one-move answer. I rather liked that, but Richard decided to add move explanation for English readers.