Quick Answer

To solve Sudoku as a beginner, fill each row, column, and 3 by 3 box with the digits 1 to 9 without repeats. Start by scanning for cells with only one possible number, then use pencil marks to track candidates. Focus on the most filled rows, columns, and boxes first, and never guess when logic can decide.

The most useful beginner tip is to work through the grid one cell at a time using two logic techniques, elimination and scanning, which solve almost every easy and medium puzzle without guessing (National Library of Medicine). Sudoku looks intimidating the first time you see a grid full of numbers, but it is one of the friendliest puzzles to learn. There is no maths involved, no trivia to know, and only one simple rule to follow. Everything else is pure logic that you can pick up in minutes. This step by step guide covers the basic rules, the two core techniques that solve most puzzles, when it is actually safe to guess, and how to practise so you steadily improve.

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The basic rules of Sudoku

Sudoku is played on a 9 by 9 grid, which is divided into nine smaller 3 by 3 boxes. The one rule is this: every row, every column, and every 3 by 3 box must contain the digits 1 to 9, each appearing exactly once. That is the entire game. The puzzle starts with some numbers already filled in, and your job is to work out the rest using logic (National Library of Medicine). There is no adding or multiplying, and a proper puzzle always has exactly one correct solution, so you never need to guess wildly.

The elimination technique

Elimination is the most important beginner skill, and it is beautifully simple. Pick an empty cell and ask which digits are already present in its row, its column, and its 3 by 3 box. Every digit that already appears in any of those three cannot go in your cell. Cross them off in your head or on paper. Often you will find that after eliminating the impossible digits, only one option remains. That digit must go there. Solvers call this a naked single, and finding them one by one will fill in a surprising amount of an easy puzzle.

The trick is to be systematic. Rather than staring at the whole grid, focus on one cell, one row, or one box at a time. Small, careful checks add up to a completed puzzle far faster than trying to see everything at once.

The scanning technique

Scanning is the perfect partner to elimination, and it works the other way around. Instead of asking what can go in a cell, you ask where a particular digit can go. Pick a digit, say 5, and look at a single 3 by 3 box. Check which cells in that box are blocked because a 5 already sits in their row or column. Often you will find there is only one cell left in the box where the 5 can possibly go. If so, that cell must be a 5, even if other digits could also fit there in theory. Solvers call this a hidden single.

Between elimination and scanning, you can solve almost every easy Sudoku and a great many medium ones without any advanced tricks at all. Master these two and you have the foundation for everything else.

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Practise on a real puzzle

The best way to learn is by doing. Try today's free daily Sudoku and use these techniques as you go.

When to guess

Here is a reassuring truth for beginners: on easy and medium puzzles, you should never need to guess. Every cell can be worked out with logic if you look carefully enough. If you feel stuck and tempted to guess, it almost always means there is a logical step you have missed, so slow down and rescan. Take a break if you need to, then come back with fresh eyes. On very hard and expert puzzles, some situations do call for a careful, structured trial where you follow the consequences of a choice until you hit a contradiction, but that is an advanced technique. As a beginner, treat guessing as a sign to look harder rather than a real strategy.

Practice tips

Improvement in Sudoku comes from regular, relaxed practice. A few tips make it stick:

  • Start easy and stay there for a while. Build confidence and speed on easy puzzles before moving up. There is no prize for struggling.
  • Play a little every day. A daily puzzle trains your pattern recognition far better than an occasional marathon. The daily Sudoku is ideal for this.
  • Use pencil marks. Jotting the possible digits in a cell helps you keep track and spot pairs and singles you would otherwise miss.
  • Do not rush. Accuracy beats speed. One wrong digit early can quietly ruin a whole puzzle, so double check before you commit.

Stick with it and you will be surprised how quickly the grid stops looking like a wall of numbers and starts looking like a puzzle you know how to unravel.

The satisfaction of a solved grid

There is a particular pleasure in placing the final digit and seeing a full, correct grid stare back at you. It is the reward for careful, patient logic, and it is available to anyone willing to learn just two simple techniques. Do not be put off by hard puzzles early on. Enjoy the easy ones, let your speed build naturally, and treat every solved grid as proof that you really are getting better at reading the patterns.