Literature
| [LIT. 1]: | Fujisawa Hideyuki, Hideyuki: |
"Igo Hatsuyōron". | |
| Heibonsha, 1st edition 25/08/1982 (Orient Library 412), 6th edition 15/03/1993, pages 241 - 246. ISBN 4-582-80412-8 | |
| [LIT. 2]: | Fujisawa Hideyuki, Hideyuki: |
"The most difficult problem ever". | |
| In Kiseido, Go World No. 29, 1982, pages 43, 47 - 49. | |
| [LIT. 3]: | Cheng, Xiaoliu: |
"Weiqi Fayanglun (new solutions)". | |
| Shurong Weiqi Publishing House, 1st edition 01/09/1988, 2nd edition 11/2003, pages 348 - 355. ISBN 7-80548-147-4 | |
| [LIT. 4]: | Redecker, Thomas: |
"The most difficult problem ever - solution". | |
| In German Go-Journal, issue 4/2005, pages 42 - 44. | |
| [LIT. 5]: | Redecker, Thomas: |
"Counter-statement to 'The most difficult problem ever - solution'". | |
| In German Go-Journal, issue 6/2005, pages 30 - 32. | |
| [LIT. 6]: | Redecker, Thomas: |
"The most difficult problem ever - still unsolved". | |
| In German Go-Journal, issue 5/2007, pages 42 - 45. | |
| [LIT. 7]: | Redecker, Thomas: |
"The most difficult problem ever - still unsolved". | |
| In German Go-Journal, issue 3/2009, pages 20 - 22. | |
| [LIT. 8]: | Fearnley, Harry: |
"Circular Hanezeki", working paper, 10/02/2011 | |
| [LIT. 9]: | Cheng, Xiaoliu: |
"Research on Weiqi Fayanglun". | |
| People's Sports Publishing House, 1st edition 01/08/2010, pages 375 - 387. ISBN 9787500936985 | |
| [LIT. 10]: | Redecker, Thomas: |
"The most difficult problem ever - Igo Hatsuyoron 120". | |
| Brett und Stein Verlag, 1st edition 06/2011. ISBN 978-3-940563-18-7 | |
| [LIT. 11]: | Redecker, Thomas: |
"The most difficult problem ever - solved by amateurs". | |
| In German Go-Journal, issue 3/2011, pages 28 - 32. | |
| [LIT. 12]: | Macfadyen, Matthew: |
"Book review: The most difficult problem ever - Igo Hatsuyoron 120". | |
| In British Go Journal, issue 158 Winter 2011-12, pages 12 - 13 | |
| [LIT. 13]: | Redecker, Thomas: |
"The most difficult problem ever - Igo Hatsuyoron 120 - Special Edition". | |
| Self-published, 2nd edition 04/2012. | |
| [LIT. 14]: | Jasiek, Robert: |
"POSITIONAL JUDGEMENT 1 / Territory". | |
| Self-published, 1st edition 2013. | |
| [LIT. 15]: | Redecker, Thomas: |
"The most difficult problem ever: Igo Hatsuyōron 120 - 300th Anniversary Edition". | |
| SmartGo Books (http://gobooks.com/books.html), 3rd edition 07/2013. | |
| [LIT. 16]: | Redecker, Thomas: |
"Igo Hatsuyōron 120: An Elephant in Slices - A novel approach to the most difficult problem ever". | |
| SmartGo Books (http://gobooks.com/books.html), 1st edition 02/2015. | |
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Internet
| Fearnley, Harry: | http://harryfearnley.com |
| Feldmann, Denis: | http://denisfeldmann.fr/bestiary.htm#index |
| Hubert, Jérôme: | http://jerome.hubert1.perso.sfr.fr/Go/vie_mort/Hatsuyoron-29s.htm |
| Jasiek, Robert: | http://senseis.xmp.net/?TheMostDifficultProblemEver#toc3 |
| Kuin, Merlijn: | http://goproblems.com/prob.php3?id=404 |
| Macfadyen, Matthew: | http://britgo.org/files/bgj/Book-Review-Igo-Hatsuyoron-120-final.pdf |
| Redecker, Thomas: | http://dgob.de/dgoz/trmdpe/index.htm |
| Sensei's Library: | http://senseis.xmp.net/?MostDifficultProblemEver |
| Tchan, Timothy: | http://tchan001.wordpress.com |
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