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Tag Archives: unique rectangle
PencilPress 81 and Master Class 110
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
Lucky Panda Books Extremely Hard 48
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
A funster Extreme 116 Labor Day Special
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
Another Look at Ardson Very Hard v.2 38
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 Sudoku multiple solutions, unique rectangle, uniqueness
6 Comments
A Run Through Ardson’s Very Hard Volume 2
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
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
THLS vs. Unique Rectangle
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
