Your first month of sudoku

Sudoku isn't hard to start — pick up a book and go. But there's a specific skill ladder, with predictable walls and predictable breakthroughs, and knowing what's coming makes the first month a lot less frustrating.

By Colin B. · Published June 7, 2026

Sudoku has a reputation for being easy to start. It is, but that phrase covers some distance. You can pick up a puzzle book today and start filling in numbers immediately. But “making progress” and “actually solving puzzles” are different things, and the gap between them closes faster when you understand the structure of what you’re learning.

This is what your first month actually looks like — the technique you need, the walls you’ll hit, and what to do when you get stuck.

Week one: The one technique that starts everything

Most beginners sit down with a sudoku and start looking at cells they can guess at. That’s the wrong approach, and it’s why puzzles seem to require luck.

Sudoku has no luck. Every puzzle has exactly one solution, reachable by pure logic. The reason it feels like guessing early on is that you haven’t learned to see the constraint structure yet.

The first technique to learn is called naked singles (also called “sole candidates”). It works like this: look at an empty cell. List every number that already appears in that cell’s row, column, and box. If only one number is missing, that’s the answer. Every easy sudoku is essentially a chain of naked singles — find one, fill it in, and it reveals more.

Spend week one just finding naked singles. Don’t worry about anything else. Easy puzzles will fall to this technique alone, often completely. When a puzzle doesn’t yield immediately, it means naked singles are hiding: you’ve filled in enough to create them, but haven’t scanned the grid carefully enough yet.

The mistake everyone makes: scanning only rows or only columns. Scan rows, then columns, then boxes — all three, for every pass through the grid.

Week two: Hidden singles and the pattern shift

After 15-20 easy puzzles, naked singles become automatic. The grid starts to feel like it has rhythm. This is when you need the second technique: hidden singles.

A hidden single is a cell where a particular number can only go in one place within a row, column, or box — even if that cell has multiple possible numbers. The cell isn’t obviously forced; the number is forced into it by elimination from other candidates.

Example: look at a row with several empty cells. Place a 7 somewhere in the puzzle and ask: given all the 7s already in this grid, which cells in this row could possibly hold a 7? If only one cell is possible, put it there. You’ve found a hidden single.

This shift — from “what can go in this cell” to “where can this number go in this region” — is the biggest early cognitive leap in sudoku. It feels awkward for a few puzzles, then suddenly obvious.

Once you can find both naked singles and hidden singles reliably, you can solve any easy puzzle. Medium puzzles will become accessible. You will still get stuck, but now when you’re stuck, you’re stuck at a real technique boundary, not just missing something obvious.

The wall most beginners hit around day 10 isn’t the puzzle. It’s switching between the two scans without forgetting to do both.

Week three: Pencil marks and the medium wall

The jump from easy to medium sudoku requires a new tool: pencil marks (also called candidates).

On medium puzzles, naked and hidden singles dry up. You can stare at the grid for 20 minutes and see no obvious move. This isn’t the puzzle defeating you — it means you need to write down possibilities, not just fill in answers.

Pencil marks work like this: in each empty cell, write in small numbers every candidate that’s still possible for that cell. Fill in the whole grid with candidates. Now scan again. New patterns emerge that were invisible before: pairs of cells in a row that each share only the same two candidates (naked pairs), boxes where a number’s candidates are all in one row (pointing pairs). These patterns let you eliminate candidates even when you can’t directly fill in a number.

You don’t need to learn all the advanced techniques in month one. Learn pencil marks first. Just filling in candidates correctly and looking for naked pairs will unlock most medium puzzles.

The most common mistake: writing in candidates for some cells but not all, then trusting the incomplete picture. Either pencil-mark the whole grid or none of it. A partial candidate grid creates false confidence.

Week four: When to move on and what to do with hard puzzles

By week four, if you’ve been solving daily, easy puzzles finish in under 15 minutes and medium puzzles feel manageable with pencil marks. This is a good moment to assess.

Don’t push to hard puzzles yet unless medium ones feel routine. The jump from medium to hard requires techniques (X-wing, swordfish, coloring) that aren’t discoverable by intuition — you need to deliberately look them up, understand them, and practice them specifically. Trying to solve hard sudoku without those techniques leads to guessing, which loops you back to the approach that didn’t work in week one.

When you do move to hard puzzles, use a technique reference alongside the puzzle book. Sudopedia (sudopedia.enjoysudoku.com) lists every named technique indexed by difficulty. When you’re stuck, identify which technique should apply, read the explanation once, and see if you can find that pattern in your current grid. This is faster than staring at the puzzle for an hour.

The right move at a genuine wall: put the puzzle down and come back tomorrow. The grid will look different after a break. Not as a metaphor — your brain actually processes differently after rest.

Beyond sudoku: when variety helps

Around the 50-100 puzzle mark, some solvers find sudoku starting to feel mechanical — the techniques become pattern-matching rather than active reasoning. This is normal and not a problem.

The fix is variety. Nonograms (Picross) use identical constraint logic but a completely different grid structure, which makes familiar reasoning feel fresh again. Kakuro blends sudoku’s number constraints with a crossword-style grid. Mensa-style logic puzzles drop the grid entirely and ask you to reason from given clues.

None of these require learning sudoku all over. The core skill — eliminating impossibilities to find what must be true — transfers completely. Most experienced puzzle solvers rotate through 2-3 types and find each one sharpens the others.

Things you’ll fail at (and that’s expected)

Every beginner hits the same walls:

• Filling in answers too confidently before candidates are clear. Pen-first solvers make this mistake constantly. The single biggest upgrade is switching to pencil and using it freely.
• Scanning rows only. You’ll miss naked singles that were obvious in columns or boxes. Build the habit of triple-scanning (row, column, box) from the start.
• Giving up just before the unlock. Stuck puzzles often have one move hiding in a corner of the grid. Before abandoning a puzzle, do a fresh candidate scan from scratch — not continuing from where you were, but starting over.
• Moving to hard puzzles too fast. Every technique in sudoku builds on the previous one. Hard puzzles are not “more of the same” — they’re qualitatively different, and struggling on them without the right techniques is just frustrating, not educational.

Nobody solves every puzzle in their first month. Finishing 70% of the easy ones and 40% of the mediums is a strong first month. The percentage climbs fast.

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Ready to actually buy the books and pencils? See our sudoku and logic puzzle gear guide for the best starter picks — including which book to begin with and the one pencil upgrade worth making.