Category Archives: Uncategorized

Andrew’s Solver Tames Worlds 200


This post walks through the “very  hard” part of the solution path taken by  Andrew Stuart’s Solver through puzzle 200 of The World’s Hardest Sudoku Book by authors unknown. This is a remarkable turn of events for a blog devoted … Continue reading

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A Coloring Trial for Only Extreme 347


Here a Manuel Castillo Sudoku sends me directly to last resort city.  Although the bv field eludes productive XY-chains or AIC, coloring is decisive enough to solve 347 in a single trial. Your first view of the grid comes with … Continue reading

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A Quiet Sysudokie Summer


Welcome to Systematic Sudoku! The weekly posts are suspended for the summer,  to be resumed September 6.  I’m leaving this overview post for those who may be encountering Sysudoku.com for the first time.  It’s to let you know what this … Continue reading

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Other Pattern Trials for Unsolvable 190


This post continues with UnSolveable 190 to point out  alternative pattern trials leading to the solution, by clearing the monster fog of candidates.. Here again is the  grid after the blue pattern trial of the first 190 post.  Considering  the … Continue reading

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Carol Vorderman’s Super Difficults


This post considers Carol Vorderman’s “difficult” collection as a practice field for the Sysudoku bypass. Carol’s tips for solving are described, and sysudokie homework on the walkthough “difficult” example is checkpointed. The review of Master Sudoku is concluded with Vorderman … Continue reading

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Hodoku Grouped AIC II


This post continues with two more Hodoku examples, which illustrate how a human solver finds grouped AIC. As usual, Hobinger attributes them to making just the right premise at just the right place. In the Hodoku Grouped AIC section, the … Continue reading

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ALS Merged Cell Forcing Chains


This post demonstrates the merger of cell forcing chains by means of ALS nodes.  I  checkpoint  three triple cell forcing chains from the challenge of the previous post, and argue that comprehensive search for cell forcing chains beyond the dual level … Continue reading

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