Author Archives: Sudent

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.

An AndrewsMcMeel  6-Star Sample 4-fills Out


Scroll back for the givens grid. After the fourth 4-fill, we never get back to the three unresolved 3-fills in the bypass trace. Here is the grid, just before SE6 (halfway down) wipes out the naked pairs. The Sysudoku basic … Continue reading

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A Filling USA Today Weekend 5-Star


Starting with a 2-fill, two 3-fills, and a 4-fill near collapse, there’s value by value action left in the bypass for only one value. Scroll back for the givens and trace out the bypass. An x-fill lists the values to … Continue reading

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A Kampelmann Hard With Bypass Coloring


Ever have a Sudoku fail to tie down a solution? Hard 109 of last post seems to fail to do so without a trial. Coloring, which has found many multiple solutions, defines the unique solution for this one. Starting with … Continue reading

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A Washington Post ****** Basic


Scroll back one for the reason for the change in plans, but this is the first of several weekend puzzles from the Washington Post, added at the last minute for additional illustrations of Sysudoku Basic solving.   Basic starts with … Continue reading

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A Harder Kampbelmann, Barely Basic


Hard 143 starts with a stingy bypass, and requires box marking and some line marking. In the bypass, a r9 3-fill resolves  into SW8and the naked pair 36. W8 then follows, either from the 8’s dublex, or  from the West … Continue reading

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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 … Continue reading

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A Hard, But Bypassed Kampbelmann 50


My Basic bypass starts with a resolved 4-fill. Did yours?  The final collapse begins with the value 8 scan resolving the naked pair left from the resolution of 3-fill c2[258]. In the bypass trace, you can discover when the previous … Continue reading

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Box Marking Subsets Maintain a CREATORS Collapse


Sysudoku weekly posts will soon be ending. This post may be the last one from the Akron Beacon Journal CREATORS series. In this one, Sysudoku box marking rescues us from a very stingy bypass, in ABJ Creators of 4/20/22. The … Continue reading Continue reading

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An ABJ Bronze With Many 4-Fill Bypass Traces


This post demonstrates the type of bypass you get by following up every resolvable 4-fill as it appears, in a less difficult puzzle. Bronze is the least difficult level announced by ABJ Creators. A similar solution path is started on … Continue reading

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Backing up to a 5-fill


Here is the Akron Beacon Journal CREATORS of 3/30/22 at the end of tracing the follow up of a 5-fill. Scanning for 5-fills is not productive. Too many, and they almost always fail. But this time, 4 of the 5 … Continue reading

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