Naked Pairs Carry the Ball in Hard 134


A second Kampbelmann Hard is tough on paper, but  gives way routinely to a systematic bypass.

Here is the grid well into the bypass, with a large number of cells held in reserve by box filling naked pairs.

In the trace, we’re at value 9, just before r5[258] is resolved.

The rest is routine follow up.

Next week, the third and last Kampbelmann,  Hard 143, is harder, carrying into line marking, after giving an opportunity to show a box 3-fill (West) in the trace.

About Sudent

I'm John Welch, a retired engineering professor, father of 3 wonderful daughters and granddad to 7 fabulous grandchildren. Sudoku analysis and illustration is a great hobby and a healthy mental challenge.
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