Tag Archives: remote pair

Classic 48 Gets to the Crayons


The second Classic of Forest’s Classic Sudoku book 30 is a strategic win for Sysudoku Advanced. X-panel keys unlock an imbalanced web of 3, 6 and 8 candidates, allowing coloring clusters to carve it into four armies, which merge and … Continue reading

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Logic Justifies Aligned Triple AIC Hinges


This post takes on a challenge puzzle 17 which follows the Figure 30.1 of the previous post, in Andrew Stuart’s The Logic of Sudoku.   A boomerang ANL shows why aligned triple candidates are eligible to be AIC hinge partners. Logic … Continue reading

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Bean’s Extremely Hard I


A review of Rebecca Bean’s 600 Extremely Hard Sudoku Puzzles with Answers begins with the review table and two puzzles, 7-6 and 12-6. The collection is mostly basic, with the half of them solved by the slink marking bypass. Puzzle … Continue reading

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Ardson Very Hard v.2 198 and 238


The review of A.D. Ardson Very Hard Puzzles v.2 continues with Ardv2 198 and 238. The sysudokie resolution to 198 is a rerun of 158, but 238 is a classic remote pair example. Ardv2 198 barely escapes the bypass, but … Continue reading

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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

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CLEF Homework on Unsolvable 190


Here is a checkpoint Sysudoku reader’s homework on the Sysudoku Cross Line Exocet Filter introduced in the previous post. Was it hard?  I stumbled many times on the 3467 case of the last week, and I may need corrections on … Continue reading

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Hodoku XY-Chains


As we explore Hodoku Chains and Loops (tech-chains.php) examples, here I contrast the premise starting, chain following school of Stephens/Hodoku, with the Sysudoku find-em-all technique of XY-rails. Also, a mathematically sensible order is suggested for remote pairs, as a Hodoku … Continue reading

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