Frequently Asked Questions About Sudoku
Find answers to the most frequently asked questions about sudoku. From basic tips to advanced techniques.
1What is sudoku?
Sudoku is a logic puzzle where you must fill a 9x9 grid with numbers 1 through 9. The goal is for each number to appear exactly once in every row, column, and 3x3 box. The puzzle starts with some pre-filled numbers and always has one unique solution.
2How do I solve a sudoku?
Start by looking for cells where only one number is possible. Scan rows, columns, and boxes to eliminate possibilities. Use pencil marks to track candidates. Work systematically and check your answers regularly.
3How long does it take to solve a sudoku?
This depends on your experience and the difficulty level. Beginners take 10-30 minutes for an easy puzzle. Experienced players solve easy puzzles in 5 minutes, while expert puzzles can take 45-90 minutes.
4Do I need math skills for sudoku?
No, sudoku requires no math! Although numbers are used, it's purely about logical reasoning and pattern recognition. The numbers 1-9 could just as easily be symbols or letters.
5Do I sometimes need to guess in sudoku?
A well-designed sudoku puzzle always has a logical solution without guessing. If you get stuck, try other techniques or take a break. Guessing can lead to errors that are difficult to correct.
6What determines the difficulty level?
Difficulty is determined by the number of starting numbers (clues) and which techniques are needed to solve the puzzle. Easy puzzles have 36-45 clues and require basic techniques. Evil puzzles have only 17-20 clues and require advanced strategies.
7What is the minimum number of starting clues?
The mathematically proven minimum is 17 numbers for a sudoku with a unique solution. Puzzles with fewer than 17 clues always have multiple solutions.
8How do I know if I made a mistake?
Use the check function to find errors, or watch for situations where no number fits in a cell. If you systematically keep notes, you can spot mistakes faster by finding contradictory candidates.
9How do I get better at sudoku?
Practice regularly with puzzles of increasing difficulty. Learn new techniques like Naked Pairs, X-Wing, and Swordfish. Analyze puzzles where you got stuck to understand what you missed. Patience and consistency are key.
10Are there sudoku variants?
Yes, many variants exist! Killer Sudoku combines sudoku with arithmetic. Diagonal Sudoku adds diagonal rules. Irregular Sudoku has irregularly shaped boxes. Each variant offers a unique challenge.