Author Archives: Sudent

About Sudent

My real name is John Welch. I'm a happily married, retired professor (computer engineering), timeshare traveling, marathon running father of 3 wonderful daughters and granddad to 7 fabulous grandchildren. The blog is about Sudoku solving. It covers how to start, basic solving to find candidates efficiently, and advanced solving methods in an efficient order of battle. It is about human solving methods, not computer solving.

Sudokuwiki Solves Only Extreme 347 by AIC


In the original Only Extreme review, OnEx 347 was an example of a coloring trial on a limited cluster generated by pattern analysis. In this update, Andrew Stuart’s solver demonstrates a solving path to a final coloring without trials, via … Continue reading

Posted in Advanced Solving, Puzzle Reviews | Tagged , , , , , , , | Leave a comment

Only Extreme 304 Scavenger Hunt


This post finishes the updated review of Only Extreme 304, displaying the Sudoku moves listed last week for the scavenger hunt. The ALS X-chain boomerang starts with the 9-chain emerging from r9c7 and terminating on the 9 candidate of ALS … Continue reading

Posted in Advanced Solving, Puzzle Reviews | Tagged , , , , , | Leave a comment

Only Extreme 304 is AIC Level


This post and the next update Castillo’s Only Extreme Sudoku review with a solution of OnEx 304 without trials. Most of the solution path is in AIC building, the most challenging level of Sysudoku Advanced. The only move prior to … Continue reading

Posted in Advanced Solving, Puzzle Reviews | Tagged , , , , , | Leave a comment

Classic Review Ends,OnEx 261 Escapes Trials


This post traces the bypass finish of Classic 240 and presents the review table for James Forest’s Classic Sudoku. Then it continues the update review of Manuel Castillo’s Only Extreme Sudoku with Only Extreme 261. Demonstrating a solution without trial, … Continue reading

Posted in Uncategorized | Tagged , , , , , , , , , , , , , , | Leave a comment

Classic 216 Bypassed and Only Extreme 132 Demoted


This post adds another bypass solving to the review of James Forest’s Classic Sudoku, Classic 216. Then a report on an update of the 10/24/17 post on Castillo’s Only Extreme 132, in which a hard, but indecisive not-both trial leads … Continue reading

Posted in Advanced Solving, Puzzle Reviews | Tagged , , , , , | Leave a comment

Classic 192 and Updated Only Extreme 3


First, a Basic trace of Classic 192. It can be solved in the bypass. In this post, James Forest’s Classic 192 is traced down in Basic. Then there’s a second Advanced level solution of Manuel Castillo’s Only Extreme 3, the … Continue reading

Posted in Advanced Solving, Puzzle Reviews | Tagged , , , , , , | Leave a comment

Classic 168 and Updated Only Extreme 89


James Forest’s Classic Sudoku 168 is a Basic level challenge.  In this post, the Classic review is continued with the 168 box marked grid, and a basic trace carrying through the collapse on the second line of line marking. Then … Continue reading

Posted in Advanced Solving, Puzzle Reviews | Tagged , , , , | Leave a comment