Most Difficult Problem Ever
Prior to the discovery of new copies of the Igo Hatsuyoron, one might have thought that Xuanxuan Qijing Problem 35, nicknamed by the French master as "the emperor of life and death problems", as the most difficult problem ever.
After the discovery of new copies of the Igo Hatsuyoron in the 1980's, it is widely believed that this is the most difficult problem ever. Composed by Dosetsu himself, it is in the words
of Fujisawa Shuko, who solved it with the assistance of some of his students), "a lifetime masterpiece, with elegant shapes, a striking novelty of the theme, a precise balance of the fights, etc."
See also:
- The Most Difficult Go Problem Ever, Go World Number 29, Autumn 1982, pages 43 and 47-49.
- A French website on this
most difficult problem including the solution.
- Better still is Denis Feldmann's
Dosetsu problem which links to
an animated solution
- The Deutsche Go Zeitung has a far more detailed discussion of
The really most difficult Go problem ever, which now has perhaps 430 diagrams, over about 280 A4 pages, as well as SGF sources, which include most established variations. All versions use the same diagrams. The main version is in German, with a good parallel (human-mediated) English translation. The Japanese, and Chinese, versions were obtained using BabelFish? to do the translation automatically, and are therefore somewhat flawed. This site is being updated and improved quite actively (as of May 2009). It now contains an introduction into the problem and an overview over the key-results in historical order (in German and English only).
- There is now an interactive version of the Deutsche Go Zeitung analysis, mentioned above. It is available at
a temporary site, and includes the English-language commentary. You can experiment with your own variations, and save the changes as a standard SGF file.
- Consider doing google searches for "120" (the problem number) and "hatsuyoron" (or the Japanese, Chinese, or Korean equivalents -- see IgoHatsuyoron). For example this could led to finding
another animated solution
Bob McGuigan: In another amazing whole-board problem, composed by Dosaku or perhaps Dosetsu, Black captures 72 stones but is unable to make a living group. I don't know of an online source but it is given as problem 20 in Nakayama Noriyuki's Treasure Chest Enigma.
f3etoiles It is online, on the site of goproblems.com, and Nakayama attributed it to Dosaku (but he may be a little bit biased in his judgment :-)) While we are on it, the same site has also the
Dosetsu problem (with a Java solution, but I believe there are some mistakes in it, and it doesn't show the 1 point victory), and another incredible full-board thing, called
No Man's Land.
Possibly the ultimate "most difficult problem ever" is: starting from an empty 19x19 board, Black to win. Currently nobody has the solution, otherwise Go would be a solved game. This problem is also often circulated as a joke.