In the blog I write as Sudent. My actual name is John Welch, from Fairlawn, Ohio, a close neighbor of Akron.
Systematic Sudoku is a six year blog about humanly practical techniques for solving Sudoku puzzles. Blog posts are released Tuesdays at 2 p.m. EST. Most current posts detail the solutions of difficult puzzles as a way of rating and reviewing published collections. A good way to get an overview is to look over the Titles page, and other support pages. To get to a particular post, use the “by month” right margin list, and scroll down to your date and title.
Early posts describe Sysudoku basic, an efficient way to begin the solution of any Sudoku, regardless of difficulty. The first major task is to find the candidates, the possible number placements, needed by advanced solving methods. Sysudoku basic includes solving in this task, keeping the grid as uncluttered as possible, and solving most puzzles you see in newspapers and magazines with pen and without advanced methods.
All beginners, and anyone wanting to understand Sysudoku basic, can prepare to plunge in with the examples on the Beginner’s page. In the posts, Sysudoku basic is introduced with an essential element, the strong link, or slink, then a walk through of the two stages of basic, box marking and line marking. With refinements on subsets, box/lines and tracing, and updates from later posts, Sysudoku basic is covered in 8 posts of October, 2011.
The next year of posts cover the advanced methods widely known in the Sudoku community, with a few exclusive to Sysudoku. Much of this is accessible via the Find It pages, which I plan to make more detailed over the next year. From then on, I have reviewed authors and collections, spending months of posts with some. The Order of Battle page is a flow chart for the entire Sysudoku procedure. Sudoku terminology is uncontrolled and fluid. The blog glossary is the Sysudoku Speak page.
In human terms, puzzles that get beyond the simplest advanced methods become unmanageable on paper and pen. The blog runs on PowerPoint and Word and these, or equivalents, are recommended for participation in “solve for checkpoint in the next post” assignments. The Tools page offers a grid template, and templates for the visual tools displayed in some posts.
Puzzles that resist all advanced methods are labeled here as Extreme, and are subject to “trials”. In a trial, sets of placements are defined. All have to be in the solution (true) or none (false). In the trial, the set is assumed true, and the puzzle is solved from there, or solving reaches a violation of Sudoku definition rules. In either case, an investment in trial sets results in considerable progress, often decisive, on the puzzle.
In the blog, trials have proven to be the human means of solving monsters, and enumerating multiple solutions. And with trials as the proper outlet, Sysudoku places no value on trial-and-error guessing of individual placements, or in the discovery of trap doors, the single unjustified clue that solves the puzzle.
Comments are welcome and complements are appreciated. Only those of interest to Sysudoku readers can be published or answered.