Rules & basics
Start here — how each variant works, why the rules exist, and how to read a grid without the basic stuff getting in your way.
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Articles on Sudoku — the techniques that crack expert puzzles, the history of the game, and the honest version of what daily play does and doesn't do.
Recent articles
Techniques
Solving easy classic sudoku
Easy classic sudoku is built around two moves and a scanning rhythm. The tier's character, where it stalls, and when you're ready for medium.
5 min read
Techniques
Solving easy killer sudoku
Easy killer is the tier where cage-sum patterns do the work that classic givens used to. Small cages, low sums, basic 45-rule, no chains.
5 min read
Techniques
Solving expert classic sudoku
Expert is the tier where X-wing, swordfish, and locked candidates enter the daily rotation. Pattern-spotting becomes the move that breaks most stalls.
5 min read
Techniques
Solving expert killer sudoku
Expert killer is the tier where the 45-rule layers onto itself, X-wings appear earlier than in classic, and innies-and-outies span multiple regions.
5 min read
Techniques
Solving extreme classic sudoku
Extreme is the tier where single-cell techniques run out and unique rectangles, X-wings, swordfish, and forcing chains carry the work. Stalling is normal.
5 min read
Categories
Techniques
Naked pairs, hidden singles, X-wings, cage combinations — the logic patterns that separate easy puzzles from expert ones.
View all →Variants
Beyond Classic: how Killer, Kakuro, and other cousins change the constraints and the kind of thinking each one rewards.
View all →Habit & wellness
The research on focus, working memory, and why a daily puzzle habit sticks better than most brain-training apps.
View all →History & culture
Where Sudoku came from, how it spread, and the people who shaped how the puzzle is solved today — Maki Kaji, Howard Garns, the variants tree.
View all →For specific solvers
Sudoku tuned to a specific kind of player — kids learning the rules, classroom teachers, parents on long drives, older adults who enjoy a daily puzzle, anyone who wants the writing pitched at them.
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