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

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

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

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

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

Solving hard classic sudoku

Hard is the first tier where pencil marks are not optional. Hidden pairs and triples, naked triples, and pointing pairs in earnest carry the work.

5 min read

Solving hard killer sudoku

Hard killer is the tier where the 45-rule becomes the daily tool, innies and outies carry the work, and cage geometry matters as much as cage sums.

6 min read

Solving master classic sudoku

Master is the tier where chain-based techniques carry real weight. XY-wings, jellyfish, single-digit patterns — the techniques that look exotic until they don't.

5 min read

Solving medium classic sudoku

Medium is the first tier where the puzzle asks you to look at two regions at the same time. Pencil marks earn their place; pairs and locked candidates do the work.

6 min read

Solving medium killer sudoku

Medium killer is the tier where the 45-rule fires on both axes and the cage-sum patterns extend beyond the singletons. The shift from arithmetic to geometry begins.

5 min read

Pointing pairs and the snake

The pointing-pair pattern is one of the most useful mid-level moves in Sudoku — and one of the easiest to miss. Here's the perceptual habit that surfaces them.

5 min read

The puzzle that taught me the X-wing

A short narrative about the specific puzzle where an experienced solver first saw an X-wing in the wild — and what made it click.

6 min read

The stopwatch problem

What timing your Sudoku does to the puzzle and to you — when speed solving helps, when it hurts, and the honest case for putting the stopwatch down.

5 min read

The thirty-second mental warm-up

The brief pause before placing your first digit — what to do in those thirty seconds, why it works, and how it changes the rest of the puzzle.

5 min read

The three grids everyone should be able to solve

Three milestones every Sudoku solver eventually clears — what each one feels like, how to know you're there, and what comes next.

5 min read

Which technique is this puzzle asking for

How to read a fresh hard Sudoku and predict which intermediate technique will break it open before you've placed a single digit.

6 min read

Easy puzzles aren't just for beginners

Why experienced solvers should still play easy Sudoku regularly — what easy does for the eye and the hand, and when to drop back down.

5 min read

Keyboard, mouse, or finger

How input method changes the experience of digital Sudoku — what keyboard, mouse, and touch do well, and what each one quietly hides.

5 min read

Reading a grid like a puzzle, not a test

The mode you bring to a Sudoku changes the Sudoku — why test-mode focus hurts your puzzling, and how to shift into puzzle mode.

5 min read

Reading pencil marks like a shape

Pencil marks aren't a list of candidates. They're a pattern, and learning to read them as one is the perceptual habit behind every mid-level technique.

5 min read

The half-finished grid problem

You've solved 60% of a hard Sudoku and the rest won't budge — here's the diagnostic tree for what's actually going on, and what to try next.

5 min read

Why the X-wing keeps tripping people up

The X-wing is a famous Sudoku technique that almost everyone knows and almost no one spots in time. Here's the perceptual problem behind it.

5 min read

From scanning cells to scanning units

The single biggest perspective shift between beginner and intermediate Sudoku — what it looks like, why it matters, and how to make it automatic.

4 min read

Knowing when to slow down

Speed is the wrong metric on a hard Sudoku — here's how to recognise the moment to slow down, and what slow looks like in practice.

5 min read

Naked and hidden pairs and triples

The mid-level extension of singles — how pairs and triples work, when each shows up, and the perspective shift that surfaces them.

5 min read

Paper versus digital Sudoku

What actually changes between solving on paper and solving on a screen, and the small habits that don't transfer cleanly between the two.

4 min read

The five mistakes every beginner makes

Five specific errors almost every new Sudoku solver makes in their first puzzles — and the small habit changes that fix each one.

4 min read

Why beginners hit walls, and what to do

The 'stuck on every cell' moment in your first puzzles is normal and has a small handful of specific causes — here's how to get past each one.

4 min read

Your first medium puzzle

What actually changes between easy and medium Sudoku, what to expect at minute three, and when to know you're ready for hard.

4 min read

Pencil marks without the clutter

When pencil marks help your Sudoku, when they hurt, and the minimal candidate-marking that gets you unstuck without burying the grid.

5 min read

The two moves that solve most easy puzzles

The naked single and the hidden single — the two foundational Sudoku moves, what each one looks like, and the perspective shift between them.

4 min read

What to do instead of guessing

Why guessing breaks a Sudoku, what 'stuck' actually means, and the practical tactics to try before reaching for a guess.

5 min read

Where to look first on a fresh grid

The discipline of the first sixty seconds — where to scan, what to count, and how to find a strong opening move on any easy or medium Sudoku.

4 min read