Tag Archives: unique rectangle

PencilPress 81 and Master Class 110

Posted on September 24, 2019 by

This post concludes the review of PencilPress’ 500+ Sudoku Extreme Puzzles, and adds another puzzle to the review update of Tom Sheldon’s Master Class Sudoku. T The final score was PencilPress Extreme 0, Sysudoku Bypass 10. If “Extreme” means requiring … Continue reading →

Posted in Advanced Solving, Basic Solving Procedures, Expert Reviews, Puzzle Reviews, Sheldon, Sheldon | Tagged , , , , , , , , | Leave a comment

Lucky Panda Books Extremely Hard 48

Posted on June 4, 2019 by

LPB 48, the first review puzzle of Lucky Panda Books 504 Sudoku Puzzles, features an interesting hidden dublex and many unresolved 3-fills with fill strings trimmed by line slinks. The easy line marking closes with a DIY unique rectangle. A … Continue reading →

Posted in Advanced Solving, Puzzle Reviews | Tagged , , , , | Leave a comment

A funster Extreme 116 Labor Day Special

Posted on September 4, 2018 by

An effective bypass, and a simple uniqueness rectangle, and three choices to close down funster Extreme 116 early. Charles Timmerman’s funster Extreme collection is less than  extreme, but a good introduction to advanced solving methods. The basic work is easy, … Continue reading →

Posted in Advanced Solving, Puzzle Reviews | Tagged , , , , , , , | Leave a comment

Another Look at Ardson Very Hard v.2 38

Posted on May 30, 2017 by

This post brings up an interesting question about the multiple solution puzzle: Does its ambiguity prevent strictly logical solving from reaching a solution? Introducing the first selected review puzzle of the A.D. Ardson Very Hard v.2 collection on April 11, … Continue reading →

Posted in Advanced Solving | Tagged , , | 6 Comments

A Run Through Ardson’s Very Hard Volume 2

Posted on April 18, 2017 by

This post begins a review of A.D. Ardson’s Sudoku Very Hard Puzzles, volume 2. The review will cover 10 pre-selected puzzles from 400, every 40 starting with number 38. Well, almost. The puzzle at the end of the previous post … Continue reading →

Posted in Puzzle Reviews | Tagged , , , , , , , | 4 Comments

Remaining THLS XV hXY Avoided

Posted on January 17, 2017 by

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 →

Posted in Advanced Solving, Berthier, Puzzle Reviews | Tagged , , , , , , | 2 Comments

THLS vs. Unique Rectangle

Posted on December 13, 2016 by

This post updates the UR chart, with credit to Denis Berthier, then debunks another unfortunate THLS pronouncement. The homework puzzle illustrates another penalty a human solver pays for interpreting  The Hidden Logic of Sudoku as solving advice. Now in our … Continue reading →

Posted in Advanced Solving, Berthier, Expert Reviews | Tagged , , , , | 4 Comments