Category Archives: Extreme Solving

Extraordinary techniques deferred past advanced ones, because of effort vs. likelihood of success.

The Especially Nice Loop of KD Insane 465


This post reports several features of an update of the post that introduced nice loop coloring. The illustrating nice loop was in itself remarkable. As shown already from books 1 through 5, KrazyDad’s hardest, the Insane collection, is hard enough … Continue reading

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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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Colorful Trials for Bean’s Extremely Hard v.10


This post calls on pattern directed coloring trials to solve IV-24, a puzzle in Rebecca Bean’s Extremely Hard, vol. 10. This one that seems to defy almost all advanced methods, and therefore, to deserve the rank of “extreme”. This also … 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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Dragging in Only Extreme 304


This post continues with three more trials, two to reach a solution, and one to guard against multiple solutions, in Castillo’s Only Extreme 304. This is getting reeeaallly extreme. Last week, we managed to extend and XY-chain across the grid … Continue reading

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Definitely Extreme 304


This post encounters what seems to be a monster in Castillo’s Only Extreme 304. A stingy basic leaves a near monster cloud of candidates resistant to the ordinary advanced repertoire. Following a theme of this review, a small coloring cluster … Continue reading

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Pattern Coloring Not-Both on Only Extreme 261


On this post of the Manuel Castillo Only Extreme review, Only Extreme 261 justifies its “extreme” label. After limited advanced moves, a pattern based coloring suggests an extension via a not-both trial on a long AIC strong link. The not-both … Continue reading

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