How to Play Sudoku: Rules and Tips

While it may look like a simple crossword game, sudoku is so much more. The sudoku grid might seem intimidating to new players, but with a little bit of determination, anyone can overcome the challenge! Sudoku (literally translated as “the numbers must remain single”) has become a mainstay of modern puzzle games. With millions of possible number combinations, Sudoku provides a brain teaser for all difficulty levels so you will have fun whether you're a beginner or ready for the hard puzzle games. Fans from all over the world have played sudoku with pen and paper, on smartphones, and even in nationally televised competitions.

The Layout

Most incarnations of sudoku are played in a 3x3 grid of squares, called “blocks.” Each block contains a smaller 3x3 grid, making the entire puzzle a 9x9 grid of small squares. Some squares will already be filled with a number before you begin. The object of the game is to fill each square’s missing numbers with a number between one and nine, without repeating a single number in a row, column, or block.

How to Play

First off, classic sudoku is a puzzle based on a small number of straightforward rules. Players can approach sudoku in a variety of ways, but the puzzle ultimately requires attention and focus to solve. Randomly placing numbers through trial and error will lead players down a path that requires intensive backtracking to fix. The best strategy is to continually examine the grid until you’ve determined the most likely location for a particular number. Using the prefilled numbers as clues, you should begin to consider what numbers could fit in each empty space. Deductive reasoning is the key!

Think about the implications of each placement. If you place a number in a certain square, what does that mean for that row? For that column? For that block? What numbers will be leftover? Methodically asking these questions before making a decision will have you filling up the grid in no time!

When first starting, the process of elimination is a useful strategy. It's great for first-time players or less difficult puzzles and involves checking to see which numbers have been already used for each square, thus narrowing down options for the empty cells.

Practice

The best way to learn is by practicing. Try it for yourself in the example below. What three numbers in the top left block will complete the puzzle? Remember not to repeat a number in a row, vertical column, or block!

Answer: the block from left to right, top to bottom, should read 2, 1, 9, 5, 4, 3, 8, 7, 6

There are a handful of sudoku variants that put twists on the original format to keep the puzzle interesting. Some variants reduce the overall number of squares, while others change the shape of the board entirely. You might even encounter a sudoku puzzle that doesn’t use numbers, but symbols or images instead. Regardless of the variation, the basic strategy of methodical deductive reasoning should get you across the finish line.

Think you have what it takes to play sudoku now? Test your reasoning powers against real opponents, and win real prizes by playing Sudoku online! Check out our selection of sudoku games online or in your app store.