Hitachi Go Problems
The Hitachi Go Problems is a weekly (biweekly from April 2018) series of life and death problems by Minoru Harada, a Japanese amateur 8 dan. Each week, two new problems will be posted, one "elementary" and one "intermediate", and the solutions to the previous week's problems will be revealed. Note that his problems are generally challenging and tricky, his typical "elementary" problems far exceed the difficulty of the beginner exercises here.
- http://www.hitachi.co.jp/Sp/tsumego/index-e.html 2,000+ problems are amassed as of 2018.
Here are a few discussions of Go problems.
- Hitachi Number 9
- Hitachi Number 314
- Hitachi Number 703 (was shown on the SL Frontpage in the 1st week of November 2009)
- zinger: Harada's problems are the best I have found on the web - always very realistic game positions. Beware the difficulty labels, however: "elementary" can be tricky, and "intermediate" can be quite hard, at least for me.
- unkx80: I would say that his "elementary" problems often verge into the intermediate/advanced territory. But it is one of the best problem collections.
- Dieter: I'm tackling these problems as part of a deliberate practice exercise. They definitely rank up with the best problem sets online, next to gogameguru's, which borrows from this collection. In the 1996 series, the difference in level between elementary and intermediate is small but noticeable, but both are easily solvable for me (2d at the time of writing).