Cho U (“Chang Hsu”) released a few different 4x4 Go puzzles/books a while ago. I think they are fun and the 105-problem book was a very enjoyable challenge for me (single digit kyu). Disclosure: I do not know Cho U or work for Nihon Kiin Publishing.
The books are in Japanese but the large amount of visual explanations means that no Japanese is needed for a Go player to read and enjoy these books. I bought mine from Amazon Japan since they seem to have the cheapest shipping by far. Amazon Japan also packages shipments much better than Amazon US so no worries there.
Not really relevant to the review, but Cho U includes fun pictures and articles when the difficulty changes. His family makes 4x4 Go puzzle cookies and cakes. And in another article he shows his daughter stacking the wooden go stones and board, just for fun. The book makes me like Cho U more as just a fun guy and a nice dad.
Sample problem (Solution at the end):
The first is a kids puzzle from 2011 (rereleased in 2020) called Yon Ro No Go (よんろのご). This puzzle comes with a cardboard board and wooden stones that look like apples on a tree. There is a 72-problem pamphlet designed as a complete introduction to Go for kids. It teaches about connecting groups, illegal plays, atari, and so on. There are several problems dedicated to each concept, really walking you through the learning process. These were too simple so I did not actually go through them. I think it would be good for kids though. If you don’t have kids, I do not recommend this product.
The second is from 2017/2018 and includes a wooden board with wooden stones and a 60-problem pamphlet. It’s called 囲碁パズル 4路盤. 囲碁 is "Go. パズル is “puzzle”. And 4路盤 means “4 row board.” This pamphlet is more focused on easier problems. I used the board to lay out the problems for the full experience, but it was a little tedious. I did this a while ago and I remember making several blunders at first. You have to train your brain to recognize that everything is in the corner, half of the board is a 2-1 point, and none of the shapes have liberties as they might usually. This pamphlet was fairly easy to complete. There are 22 1-star difficulty problems, 18 2-star, and 20 3-star problems. I found the 1 star problems to be easy and solvable at a glance. Or, at least they were after I made a bunch of blunders in the first few problems as I learned how 4x4 Go works. The 2 stars required some thought and I did make a few mistakes like not reading out the best defense or forgetting a lack of liberties. The 3 star problems required a bit more thought but they were not too hard to solve. I liked having the board and stones but if you don’t see yourself using those, I would skip this product and just get the 105-problem book, discussed below.
The third is a 105-problem collection that was released in 2018 (shown above). This book has 36 1 star problems, 40 2 star problems, 24 3-star problems, and 4 “special” problems. The name of this book is 囲碁 パズル 4路盤 問題集 105. I don’t think these are repeats from the 60-problem pamphlet but I did not go through and compare. I ended up just reading the book and not using the wooden 4x4 board and stones. I found the difficulty rankings to be similar to the 60-problem pamphlet but now I was more used to 4x4 Go and so I made fewer blunders. I liked that this book included more problems and had a higher proportion of difficult problems. I found the 1 and 2 star problems to be easy and fun while the 3 star problems felt like normal tsumego difficulty. Many tsumego rely on the special properties of the corner to solve and these 4x4 Go problems really focused my mind into using those techniques. I would recommend this book to single digit kyus that are looking for more interesting tsumego.
I also like how Cho U simplified tsumego techniques:
- Use Miai and double-atari.
- Look for Danten (cutting point) and Kiru (cut) or Tsunagu (connect).
- Setup uttegaeshi (Snapback)
- Put the opponent into damezumari (shortage of liberties) so they cannot atari you without self-atari.
5. Me ari me nashi (eye vs. no eye).
6. 3 moku nakade (3 space dead shape). Avoid seki.
7. Ishinoshita (under the stones)
8. The center is the vital point of a symmetrical shape
9. Semeai (capturing race) with nakade. Take the vital point without making eyes to win/avoid seki.