Tag Archives: hidden pair

Readers Solve Ultrahardcore 3


This post returns to the Stefan Heine’s utrahardcore  3 solution path just before cell and unit forcing chains. It turns out that an immediate coloring trial reaches a solution without them. Then we report how two Sysudoku readers solve it … Continue reading

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FTSPAH 104 and 144


The review of the unspeakable FTSPAH continues with two more puzzles selected arithmetically. The basic trace of FTSPAH 104 is Sysudoku Basic at its best. A near collapse in the bypass is extended by a deferred hidden dublex, which 104 … Continue reading

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A Well Hidden Pair in Only Hard 128


This begins a brief review of Manuel Castillo’s Only Hard Sudoku, preliminary to reviewing his more recent Only Extreme Sudoku. Both books are wordless collections of 400 puzzles, with identical formats. Thanks go to officers, members and guests of the … Continue reading

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