-
Recent Posts
Recent Comments
Sudent on KrazyDad Super-Tough 555 Proxy on KrazyDad Super-Tough 555 Sudent on Ultrahardcore Review ALS-wings… Strmckr on Ultrahardcore Review ALS-wings… Sudent on Krakening a Finned Fish Archives
- July 2022
- June 2022
- May 2022
- April 2022
- March 2022
- February 2022
- January 2022
- December 2021
- November 2021
- October 2021
- September 2021
- August 2021
- July 2021
- June 2021
- May 2021
- April 2021
- March 2021
- February 2021
- January 2021
- December 2020
- November 2020
- October 2020
- September 2020
- August 2020
- July 2020
- June 2020
- May 2020
- April 2020
- March 2020
- February 2020
- January 2020
- December 2019
- November 2019
- October 2019
- September 2019
- August 2019
- July 2019
- June 2019
- May 2019
- April 2019
- March 2019
- February 2019
- January 2019
- December 2018
- November 2018
- October 2018
- September 2018
- August 2018
- July 2018
- June 2018
- May 2018
- April 2018
- March 2018
- February 2018
- January 2018
- December 2017
- November 2017
- October 2017
- September 2017
- August 2017
- July 2017
- June 2017
- May 2017
- April 2017
- March 2017
- February 2017
- January 2017
- December 2016
- November 2016
- October 2016
- September 2016
- August 2016
- June 2016
- May 2016
- April 2016
- March 2016
- February 2016
- January 2016
- December 2015
- November 2015
- October 2015
- September 2015
- August 2015
- July 2015
- June 2015
- May 2015
- April 2015
- March 2015
- February 2015
- January 2015
- December 2014
- November 2014
- October 2014
- September 2014
- August 2014
- July 2014
- June 2014
- May 2014
- April 2014
- March 2014
- February 2014
- January 2014
- December 2013
- November 2013
- October 2013
- September 2013
- August 2013
- July 2013
- June 2013
- May 2013
- April 2013
- March 2013
- February 2013
- January 2013
- December 2012
- November 2012
- October 2012
- September 2012
- August 2012
- July 2012
- June 2012
- May 2012
- April 2012
- March 2012
- February 2012
- January 2012
- December 2011
- November 2011
- October 2011
- September 2011
Categories
- Advanced Solving
- Alary
- Barker
- Basic Solving Procedures
- Berthier
- Expert Reviews
- Extreme Solving
- Gordon
- Gould
- Green
- Hanson
- Heine
- Hobiger
- KrazyDad
- Longo
- Monster
- Nakamoto
- Pitkow
- Puzzle Reviews
- Sheldon
- Sheldon
- Shortz
- shye
- Snyder
- Stephens
- Stuart
- Sudoku Toolware
- Sysudoku History
- Tom Sheldon
- Uncategorized
- Weekly Extreme
Meta
Category Archives: Berthier
A Closing ALS Postscript on THLS
This post demonstrates ALS-XZ as an alternative to hidden XY chains, and concludes the review of The Hidden Logic of Sudoku by Denis Berthier. In THLS, Denis goes outside the Royles 17 collection only a few times for illustrative examples. … Continue reading
Posted in Advanced Solving, Berthier, Expert Reviews, Extreme Solving
Tagged ALS-XZ, Denis Berthier, Gordon Fick, The Hidden Logic of Sudoku, UR Type 2, XY-chain, xyt-chain
4 Comments
Berthier’s xyzt Chain
This post concludes my reading of Denis Berthier’s The Hidden Logic of Sudoku, with two example puzzles to illustrate his xyzt-chain. While it is good to be aware of Berthier’s “t” versions of classic XY chains, I don’t recommend a comprehensive … Continue reading
Berthier’s xyt-Chains Rated Extreme
This post suggests a limited role for Denis Berthier’s xyt chain in human solving. I found no THLS examples of longer chains not requiring prior xyzt or hidden chains.The last prospect, Royle 17-33442 proves to be both unjustified and unnecessary. … Continue reading
An xyt Color Wrap
In the spirit of Valentine’s Day, I come across a coloring resource in Berthier’s xyt chain. The elaboration of Royle 17-20565 in Chapter XVII of The Hidden Logic of Sudoku is a challenge in itself. By the theory of looking … Continue reading
Berthier’s xyt-chains in THLS
Next we review the introduction of xyt-chains in The Hidden Logic of Sudoku. These are modified XY-chains which allow extra candidates in the chain cells, and unlike regular XY-chains, make eliminations regardless of whether the chain starting candidate is true … Continue reading
A Chicken Chok’in Checkpoint on Unhidden Chains
This post checkpoints Royle 17-16774, a rare example in The Hidden Logic of Sudoku of conjugacy chains dealing with a monster cloud of candidates. The checkpoint also catches SudoRules dismembering a “useless” XY nice loop that somehow sneaked into THLS. … Continue reading
THLS Limps In On Chains
This post identifies the conjugacy chain, the last fundamental chain type to be introduced in The Hidden Logic of Sudoku, as a weakened X-chain. Since the last few chapters introduce extensions for XY chains, it becomes clear that THLS is … Continue reading
Posted in Advanced Solving, Berthier
Tagged c-chains, color wrap, Denis Berthier, near BUG, nice loop, remote pair, Reverse XY chains, swordfish, The Hidden Logic of Sudoku, uniqueness, X-chains
2 Comments
Remaining THLS XV hXY Avoided
Here we complete the report on the puzzles selected in The Hidden Logic of Sudoku to show that hidden XY chains are an “inescapable tool for the advanced player”, and therefore require the generation and maintenance of symmetry grids. None … Continue reading
No THLS Case for Hidden XY Chains
This post and the next demonstrate that the examples presented in The Hidden Logic of Sudoku as requiring “Hidden” XY Chains actually have alternative, and much less demanding, resolution paths in the Sysudoku repertoire. The burdensome maintenance of symmetry grids is … Continue reading
Hidden XY Chains Are Reverse XY AIC
This post demonstrates that every hidden XY chain has a recognizable AIC counterpart on the normal grid, nrc space. That means it is not necessary, if you are AIC literate, to generate and maintain the grid spaces in which hXY … Continue reading
Systematic Sudoku 