Sudoku has exactly one rule: fill the 9×9 grid so that every row, every column and every 3×3 box contains the digits 1 to 9 exactly once. No maths is involved — the numbers could be replaced by nine shapes and the puzzle would play identically. What beginners need is not calculation but a scanning routine. These ten tips give you one. You can use this 10 Sudoku Tips for Absolute Beginners free on IlmHunt — no sign-up needed, and it runs entirely in your browser.
1. Start with the digit that appears most
Count which digit shows up most often among the given numbers. If the puzzle hands you five 7s, those five positions already block their rows, columns and boxes, and the remaining 7s are heavily constrained. Placing the most-given digit first gives quick early wins and teaches you how eliminations work before the harder digits.
2. Scan in one direction at a time
For each missing digit, scan row by row: pick a row, note which digits it lacks, then check each empty cell against its column and box. Beginners tend to stare at the whole grid hoping numbers reveal themselves. A fixed routine — digit by digit, row by row — finds placements that staring never does.
3. Use pencil marks (candidates)
When a cell could be two or three different digits, write the small possibilities in the corner instead of guessing. Pencil marks turn memory into information: a row whose cells show candidates {2,5}, {2,5} and {5,9} is telling you something (see tip 6). On paper, use light pencil; nearly all frustration in Sudoku comes from trying to hold candidates in your head.
4. Cross-hatch each 3×3 box
Pick a box and a digit missing from it. Now look at the rows and columns crossing that box: if the digit already appears in two of those lines, they are eliminated, and the digit’s cell inside the box is often forced. This technique — cross-hatching — solves most easy puzzles on its own and is the backbone of every harder method.
5. Look for naked singles
A naked single is a cell whose pencil marks have been reduced to exactly one candidate. It happens constantly as you fill other numbers, so re-scan the grid after every few placements. Each naked single you place triggers fresh eliminations around it; puzzles often collapse in a chain once you start catching them all.
6. Spot naked pairs
If two cells in the same row, column or box both show exactly the same two candidates — say {3, 8} and {3, 8} — then those two digits are locked between those two cells, and you can erase 3 and 8 from every other cell in that unit. You still do not know which cell holds which, but the eliminations frequently expose a naked single somewhere else in the row.
7. Find hidden singles
A hidden single hides in a messy cell: within one row, column or box, a digit can go in several cells by elimination, but if every other empty cell in that unit is blocked for that digit by its own row/column/box, the digit has exactly one legal home — even if that cell’s pencil marks list four candidates. Ask of each unit, for each missing digit: “where can this digit still go?” If the answer is one cell, fill it in ink.
8. Never guess
The moment you write a number “to see if it works”, the puzzle stops being checkable — a wrong guess looks identical to a right one until the contradiction surfaces twenty minutes later. Every number in a well-made Sudoku follows logically from the givens. If you are stuck, you are missing a technique, not a lucky guess. Guessing also robs you of the skill you are building.
9. Work the crowded areas, rest the empty ones
Rows, columns and boxes that already hold six or seven digits are nearly solved and yield to simple elimination. The wide-open corner of the grid will get easier on its own as the crowded areas resolve, because every placement sends eliminations outward. Keep rotating: finish what is finishable, then return to the hard region with new information.
10. Take a break when you stall
Staring fatigue is real: after ten stuck minutes your eyes skip the same cell repeatedly. Walk away and return — the placement you missed will often be visible within seconds, because your brain kept processing the pattern. This is not superstition; it is how visual scanning works, and it applies to word puzzles just as much — ask anyone who has returned to a crossword and seen the answer instantly. Speaking of which, our Crossword Solver and the rest of the Word Tools hub are ready when your Sudoku is done.