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How to Play Sudoku

While Sudoku puzzles can be rather challenging, the rules and general game play are pretty simple and straightforward.

Each column, row and nonet needs to contain the numbers 1-9, and each number can only be used once.

That's it. That's all the rules. Think you have what it takes?

About Sudoku

Our free online version of web Sudoku follows in the number puzzle's classic tradition, no pen or pencil needed! As you start the puzzle you can choose your sudoku difficulty. We offer Sudoku for beginners, medium sudoku, and Sudoku for experts. Additionally, the puzzle is updated daily, giving you a new Sudoku challenge each and every day!

Sudoku History

Sudoku puzzles have a rich history.

Number puzzles became popular in the late 1800s in France, when newspapers began to publish partially-filled number grids on their pages. The number puzzles were not the exact same as sudoku, though, because they contained some double-digit numbers and did not have sub-squares. The rows and columns did, though, add up to the same number.

These number puzzles disappeared around World War I, but reemerged in 1979 when an Indiana man named Howard Garns published the first modern Sudoku puzzle. His Sudoku used a 9x9 square, and all rows and columns needed to contain the numbers 1-9. Sudoku games were introduced in Japan five years later, where the number puzzles became immensely popular and were officially coined 'sudoku.' In 2004, The Times in London published its first daily sudoku, reintroducing the Sudoku puzzle to Western culture. Sudoku quickly spread to newspapers all over the world, delighting users every single day.

Of course, free Sudoku puzzles that can be played only at any time or day soon followed.

Tips to Solve Sudoku Puzzles

The most basic technique for solving Sudoku puzzles is to use the scanning method. This involves picking a number and then looking at rows and columns across the grid containing that number. The goal is to look at all the boxes where the number can’t be placed, hopefully leaving the one box where it should be.

Scanning is especially effective when you’re looking at both rows and columns at the same time. In grids with many unfilled squares, this is often the only way to narrow down where to place a number.

This process of elimination is a fast, easy, and highly effective method to solve lower-level puzzles. Even when solving a hard puzzle, it’s a great opening move to fill in a good number of squares.

However, there will come a point when the scanning method mentioned above won’t cut it. Here is where using pencil marking comes in. The idea is to use a pencil to fill a space with all possible number combinations. You’ll then analyze the whole board to figure out which number combinations work.

One common problem you’ll encounter is a disjointed pair. This is when two numbers can only be placed in two squares, but you don’t know which number goes into which space. When such pairs are apparent, it’s called a naked pair. Otherwise, it’s referred to as a hidden pair.

While you can’t solve disjointed pairs directly on their own, you can use them to deduce where other numbers should be. For example, if you have three spaces left on a grid, and two of those is a disjointed pair, then you know the third number can only be placed on the remaining space.

A very advanced approach for solving truly challenging puzzles is the X-Wing technique. This happens when the spaces you’re trying to solve form an X shape or are in the corners of an imaginary square. This gives you a new logic constraint that allows you to eliminate spaces further. While useful, the X pattern required for this technique is pretty rare in practice.

The Benefits of Playing Sudoku Daily

Sudoku isn’t just a fun game to pass the time. It also has several health and wellness benefits. Like any puzzle, an easy Sudoku game can be a great way to reduce stress and anxiety. That’s because the game requires focus and concentration, which can distract you from negative thoughts or emotions. As a result, many people report having a sense of calm and relaxation after playing even a single Sudoku puzzle.

The brainpower required with Sudoku also has excellent mental benefits. It’s a great way to expand your logical thinking and problem-solving skills. In addition, the more you play, the more you’ll develop patterns and methods of analysis, which you can easily apply to a variety of real-life situations.

At higher difficulties, Sudoku can even help expand your memory capacity. More complex puzzles require you to note multiple possible number combinations and recall past strategies that you can apply.

The easy rules of Sudoku also make it easily accessible for anyone. As a result, it can be a great developmental tool for children and mentally stimulate the adult brain to help prevent many mental disorders.

Sudoku can also help promote a healthy mental state. It can make you more resilient against seemingly impossible obstacles. And when you solve a challenging puzzle, it can provide a fantastic feeling of accomplishment and pride. By constantly trying to beat your own best time, you also develop healthy competition with yourself (or others!)

And the best part is that you can easily play Sudoku online, free, anytime — no download required! So, there’s no reason not to make this addictive puzzle game part of your daily routine.