Tag Archives: forcing chains

Cell Forcing Chains


Here we examine forcing chains starting from all candidates in a cell.  When the number of chains is 2, there is nothing new.  Above that,  there is a new strategy to explore, which rivals LPO in complexity, but falls behind … Continue reading

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Digit Forcing Chains?


Is Andrew Stuart’s Digit Forcing Chains a useful new solving technique? Actually, no.  Andrew’s  sudowiki site introduces digit forcing chains with examples that raise – and seem to settle – that question. Needless confusion is created by this unwarranted introduction. First, have you … Continue reading

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Unsolvable 40 is Solved?


In the last post, Unsolvable 40 was staggered by a remarkable combination of coloring and LPO.  Only one pattern, 8b, was removed by LPO conflicts.  But other conflicts combined to force another pattern 8c to the color blue in an … Continue reading

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