Rules and Techniques
Rules and solving techniques for the three games, written for people who have never played and for people who are stuck.
Last updated: September 29, 2026
In this section
- Sudoku rulesThe rule of Sudoku in one sentence, the words players use, a worked first example and the mistakes beginners make most often.
- Sudoku techniquesSeven Sudoku solving techniques in order of difficulty, from singles to X-wing, each with an example. They are all the daily puzzles ever need.
- Sudoku X-wingHow the X-wing works in Sudoku, how to spot one, and two practice positions from this site’s hard puzzles where no simpler technique helps.
- Nonogram rulesHow to read the clues of a nonogram, what filled and crossed cells mean, and a complete small example solved step by step.
- Nonogram techniquesFive nonogram techniques that work on one line at a time: overlap, counting slack, edges, crossing out and splitting. With examples and a formula.
- Minesweeper rulesWhat the numbers in Minesweeper mean, how opening and flagging work, how a game is won or lost, and what is different about the daily board.
- Minesweeper techniquesThe three rules of reasoning that solve every daily Minesweeper board: counting around a number, comparing two numbers and counting the remaining mines.
- Minesweeper patternsThe Minesweeper patterns 1-1, 1-2, 1-2-1, 1-2-2-1 and a pattern around a corner, with diagrams, practice boards and the reasoning that proves each one.
Where to start
Each game has two main pages. The rules page explains the board, the goal and the vocabulary, with a first example. The techniques page explains the ways of reasoning from the simplest to the hardest, each with an example and with the mistakes that go with it. Two more pages go deeper, each with practice positions: the X-wing for Sudoku and the common patterns for Minesweeper.
If you have never played a game, read its rules page and then try the easiest puzzle of the day: the easy Sudoku, the 10 × 10 nonogram, or the Minesweeper board.
How the guides fit the puzzles
The daily puzzles are checked by solver programs before they are published. These solvers use a fixed list of techniques, and the techniques pages explain exactly that list.
| Game | Techniques |
|---|---|
| Sudoku | Singles; locked candidates and naked pairs; hidden pairs, naked triples and X-wing |
| Nonogram | Reasoning on one row or column at a time |
| Minesweeper | Counting around one number; comparing two numbers; counting the remaining mines |
This means that a technique which is not explained here is never needed for a daily puzzle. Other techniques exist and may be faster, but you can do without them.
Tools that go with the guides
Five tools go with the guides. The Sudoku solver shows the steps of a grid you enter, as far as the seven techniques reach, and names the technique of each step. The no-guess Minesweeper page builds unlimited boards that never need a guess, and its hint names the rule behind the next move. The printable Sudoku page prints the daily puzzles with the answers on a separate page, the cage combinations page lists every set of digits that fits a killer sudoku cage of a given size and sum, and the nonogram solver works through the clues you enter one line at a time and says whether they need a guess or have more than one solution.
Example: using a guide while you play
Suppose you are stuck on a medium Sudoku. The level table on the Sudoku page says that medium puzzles need locked candidates or naked pairs. Open the techniques page, read these two sections, and look for them in your grid: a digit that fits in only one row or column of a box, or two cells of a unit that share the same two candidates.
Common mistakes
- Reading all techniques before playing. Learn one, use it in a few puzzles, then learn the next.
- Skipping notes in Sudoku. The techniques beyond singles work on candidates, and candidates have to be written down.
- Treating a technique as a rule of the game. The rules are short; techniques are conclusions drawn from them.
Frequently asked questions
- Which game is the easiest to start with?
- The easy Sudoku needs only the first step of its techniques page, and the 10 × 10 nonogram is small enough to learn on. Minesweeper is quick to learn as well, but a single wrong move ends the game.
- Do I need mathematics?
- No. Sudoku uses digits as nine different symbols and needs no arithmetic. Nonograms and Minesweeper need counting and small subtractions.
- Are the guides written for these puzzles only?
- The rules and techniques are general and work for the same games anywhere. What is specific to this site is the guarantee of which techniques are enough.
- Who wrote the guides?
- The texts were written for this site with the help of an AI system and checked against the behaviour of the puzzles and their solver programs. If you find a mistake, please tell us.