- Two extra tiers: Very Hard & Expert
Play for free on 'Easy'–'Medium'–'Hard'. Exclusive to Zaphira Plus: Very Hard and Expert.
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Sudoku is the perfect logic puzzle for anyone who wants to train their brain. The classic 9x9 grid challenges you to place the numbers 1 to 9 cleverly. The rule is simple: each number may appear only once in every row, column, and 3x3 block, just like you may already know from Spiegel Sudoku. Whether you’re a beginner or a pro — with difficulty levels ranging from Easy to Very Hard, you’ll always find the right challenge. Playing Sudoku is not only fun, but it also improves your concentration and boosts logical thinking.
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Tips & Tricks for Sudoku
Tip #1: Start easy
Begin with the fields that allow only one possible number. These “easy hits” help you get an overview and make it easier to start in Sudoku.
Begin with the fields that allow only one possible number. These “easy hits” help you get an overview and make it easier to start in Sudoku.
Tip #2: Check rows and blocks
Check each number not only in rows and columns but also in the 3x3 blocks. Using systematic elimination, you often uncover hidden possibilities.
Check each number not only in rows and columns but also in the 3x3 blocks. Using systematic elimination, you often uncover hidden possibilities.
Tip #3: Note candidates
Use small notes to write down possible numbers in empty fields. As the puzzle progresses, gradually narrow down and eliminate these candidates.
Tip #4: Eliminate duplicates
Remember: Each number from 1 to 9 may appear only once in every row, column, and block. Systematic elimination moves you forward step by step.
Remember: Each number from 1 to 9 may appear only once in every row, column, and block. Systematic elimination moves you forward step by step.
Tip #5: Work step by step
If you get stuck, focus on areas with only a few empty cells. These are where you’re most likely to make quick progress.
Tip #6: Patience and logic
Sudoku doesn’t require guessing — it’s all about logical thinking. Take your time, stay focused, and keep an overview to solve the puzzle without mistakes.
Sudoku doesn’t require guessing — it’s all about logical thinking. Take your time, stay focused, and keep an overview to solve the puzzle without mistakes.
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Instructions for Sudoku
1. Basics
Sudoku consists of a 9x9 grid divided into nine smaller 3x3 blocks. The goal is to fill all cells so that each number from 1 to 9 appears exactly once in every row, column, and block. At the start, several numbers are already given to help you get going. These so-called “starting numbers” form the base of your strategy. Sudoku requires no math — only logical thinking and careful elimination.
2. Progress
Progress in Sudoku is made step by step through logical reasoning. First, fill in the obvious cells that allow only one possible number. Then use elimination by checking which numbers are already present in rows, columns, or blocks. Notes help you keep track of candidates and narrow them down when needed. With every correct entry, new opportunities open up to fill other cells safely. The puzzle grows gradually until the entire grid is completed correctly.
3. Time
Time also plays an important role in Sudoku. The goal is to solve the puzzle as quickly and accurately as possible. The shorter your time, the higher your score will be. This time component adds extra excitement and turns every match into a small challenge. At the same time, it motivates you to keep improving your speed. With regular practice, you’ll become faster and more confident — until you can master even tougher Sudokus in impressively short times.
FAQ for Sudoku
Yes, every Sudoku has a unique solution and is always solvable. You should never have to guess — with logical thinking, you can always find the right path.
If you can't find any more solutions, switch to notes mode and choose a cell that only has two possible candidates. Try out one candidate in notes mode. Ideally, you will be able to solve the puzzle without any mistakes based on this. Alternatively, the test candidate may turn out to be wrong and lead to a double digit within a unit. No problem, because mistakes don't count in note mode. You can deduce that the other candidate belongs in the corresponding cell. So delete all notes, switch to game mode, enter the digit, and then try to find more solutions. If that doesn't work, go back to note mode.
Absolutely! Sudoku is a pure logic puzzle. You don’t need to calculate — it’s all about logical reasoning. The numbers 1–9 are just interchangeable symbols; the game would work the same way with letters or pictures.
Start with easy Sudokus and work your way up. Learn the basic techniques first, and use our jokers — shown here as lightbulbs. Practice makes perfect — the more you play, the more intuitive the solving steps will feel.
Yes, in addition to the classic 9x9 Sudoku, there are many variations. On our site, however, you’ll find the traditional Sudoku in five different difficulty levels, similar to Spiegel Sudoku. You can choose between “Easy Sudoku,” which is perfect for beginners, “Medium Sudoku,” “Hard Sudoku,” “Very Hard Sudoku,” and, for true pros, “Expert Sudoku.”
