Your first medium puzzle

If you've solved a stack of easy Sudoku puzzles and you're thinking about stepping up, here's the honest version of what's about to happen. Medium isn't "harder easy" — it asks for techniques easy didn't, and the moment you notice that is usually the moment you decide whether the next stage of Sudoku is for you.

Most solvers find the easy-to-medium jump bigger than they expected, and the medium-to-hard jump roughly the same size. So treat the first medium puzzle as a small learning event, not a test.

What actually changes

Easy puzzles are mostly solvable with naked and hidden singles — your eye finds them, you place them, and the constraints tighten until the grid finishes itself. Medium puzzles run out of singles earlier. Somewhere around thirty to fifty per cent solved, you'll hit a moment where no obvious single jumps out, and the grid stops yielding to scanning alone.

That moment is by design. Medium puzzles are calibrated to require pencil marks and a couple of more advanced techniques — typically naked pairs, pointing pairs, or box-line interactions — to break through the middle. The puzzle isn't broken. You're at the level of the puzzle's design.

What it'll feel like at minute three

The classic medium-puzzle experience: you cruise through the first ten or twelve placements like you're solving an easy. Then it slows down. You stare at one or two cells that feel constrained but you can't quite see why, and your eye starts hunting for a naked single that isn't there.

At this point a beginner often does one of three things. They guess, which breaks the puzzle (and we have a piece on what to do instead of guessing for that exact moment). They give up and switch to easy, which trains an unhelpful stuck-equals-quit habit. Or they pick up the pencil and start pencil-marking the most-constrained cluster — which is the move that actually unlocks the puzzle.

When pencil marks become non-negotiable

On easy you can solve without pencil marks if you're disciplined. On medium you usually can't. The reason is that medium-tier moves often require seeing patterns across multiple cells: naked pairs depend on noticing two cells in the same unit share the same two candidates, and pointing pairs depend on seeing two of a digit's candidates lined up inside one box. You can't see those patterns without writing the candidates down somewhere.

Our piece on pencil marks without the clutter covers the minimum-marking strategy that works best for medium. The short version: mark only the most-constrained region first, look at the cluster, and let the patterns surface from a sparse marking rather than a full-grid annotation.

How to know when you're ready for hard

Medium has a reliable signal. When you're finishing most medium puzzles in eight to twelve minutes, recognising naked pairs without pencil-marking the whole grid, and rarely getting truly stuck for more than a minute, you're ready to try a hard puzzle.

Hard introduces another tier of techniques — X-wings, swordfish, advanced colouring patterns — and the same thirty-to-fifty-per-cent wall is steeper. The discipline you built on medium transfers cleanly: scan, mark sparingly, look for patterns in clusters, place, repeat. The technique surface is bigger but the workflow is the same.

Your first medium puzzle is going to take longer than your last easy puzzle by a meaningful margin. That's normal, and it's good. The puzzle is asking you to learn a new move; the move will become natural over the next five or ten medium puzzles, and then medium will start to feel like a faster easy. That's the rhythm of every difficulty step on the way up.