How to play sudoku

How To Play Sudoku: The Ultimate Guide to Beating Any Puzzle

“Why does that number go there!?”
“How do you know?”
“I don’t get it!”
Do you find yourself making these comments? Then you have found the perfect guide to Sudoku for beginners (and experienced players who really want to master Sudoku).
Sudoku puzzles can be very challenging, however, you will be learning how to break these challenging puzzles down into simple, solvable pieces so you can quickly and easily complete even the most difficult Sudoku boards and layouts!
We will be using some different techniques to solve puzzles at all levels. This Sudoku guide will take you from the bare basics to mastering the hardest puzzles. You’ll have the chance to slowly learn all the skills and test out this new way of solving puzzles right on this page.

Solving Sudoku Puzzles

We will be using some different techniques to solve puzzles at all levels. This book will take you from the bare basics to mastering the hardest puzzles. You’ll have the chance to slowly learn all the skills and test them all in the end!
Whether you are new, or you thought that learning Sudoku was impossible, you have come to the right place. This will be a thorough walkthrough so you can fully grasp how the game functions.
We will be learning how to use techniques to solve different obstacles commonly found in these puzzles. Dear reader, I hope that this little guidebook to Sudoku will bring you years of fun and that you pass on the game to friends and family you care about!

A Sudoku Puzzle Challenge

This is the puzzle we are going to solve today.

If that looks impossible to you, don’t worry! I’m going to show you how to solve this very challenging Sudoku puzzle.
Here’s the solved puzzle:

Now let’s work backwards to see the principles of Sudoku success from the ground up.

How to Play Sudoku

In Sudoku, you must complete the grid so each row, column, and 3-by-3 box (in bold borders) contains every digit 1 through 9.
No row, column, or 3×3 box can feature the same number twice.
That means each row, column, and 3×3 square in a Sudoku puzzle must contain ONLY one 1, one 2, one 3, one 4, one 5, one 6, one 7, one 8, and one 9.
Let’s visualize these instructions.

Each row has 1 through 9 in it. If this is true, then we can solve every column.

Solving Sudoku Rows and Columns

Which number is missing, 1 through 9, in this column above?
Your answer was 5! Congratulations! Now try and solve each column and find each missing number from 1 through 9.

Solving 3×3 Sudoku Squares

Speaking of squares, let’s solve one and walk through it. Now keep in mind, every column, row, and square has 1 through 9 in it. So let’s use that to our advantage. First we will find where the number 1 fits.

Rule Out Impossible Numbers

The blue lines indicate that the row or column has a 1 within it. The red box shows its location within that row or column. As we can see here, there is only one proper space for 1 to go.

Let’s continue with finding 2 in the same manner.

Again there is only one proper place for 2.

Now let’s try figuring out where the 3 goes in this puzzle.
Draw the lines with your finger or pencil to block off all the rows and columns in which a 3 cannot appear.

Did it work? Now let’s try your method on 4. Find the correct slot for 4 by looking at the other squares for data just like we did for 1, 2, and 3.

Well Done! Use this method and solve for the rest of the square.

Your completed square should look like this:

Now you have the basic concept of the rules and how they function. You also developed a method to check your work and verify that your answer is correct.
If not, start again and try a different method. There are several different ways to reach the answer. Also, skim ahead and see if you can find a pattern to these puzzles. They will reveal themselves as the puzzle is being solved.
Let’s try and find 1 through 9 again in a different way.

We will start by solving the first square. 1 through 9, which number is missing?

Now that we have solved the square, we can solve for the row and column. Find which numbers are missing in the row, and then in the column, 1 through 9.

Now see if you can fill the rest of the puzzle, 1 through 9.

Very good! We have mastered the art of 1 through 9! Now let’s try some different puzzle patterns and strategies.

In this puzzle most of the 3’s and 7’s are missing. Let’s work through.

You can start anywhere on the puzzle, but we will start here.

This particular column is only missing one number.

If we were to start from here, we really can only guess what the answer may be. By looking for absolute answers, you will always be able to solve the puzzle correctly. So let’s come back to this particular slot in a moment.

Go ahead and solve the column. What’s missing?

Now maybe we cat get a real answer to one of our original inquiries. Fill in the slot.

Now place the other 3’s and 7’s in their designations.

How’s that puzzle look? Let’s test your identification skills.

Which number is missing?

It was 5!

Level 1 Sudoku Puzzle

I think we’re ready for a real puzzle. Let’s start with a simulated level 1 puzzle.

Let’s put our reasoning skills to the test. Let us also use the rules of the game against itself. Take this first square for example. 1 through 9, we are missing 2, 5, and 9. Let us try and solve for 2.

We can see with the available data that there is only one true place for 2 inside the square. Every column, row, and 3 by 3 square has 1 through 9 in it. Rules that allow elimination until one true answer remains.

Now let’s solve for 5 using the same process.

Again we can see there is only one place for 5.

And seeing as there is only one slot in the square that is empty, the logical answer would be…

9!

Let us continue to the next square.
There are two numbers missing from this square.

There is one number missing from this row.

Solve for that number.

Now solve for the square!

Very good! Now solve this square.

Now let’s take it up a notch.

Let’s solve this particular slot.

Note that this square is missing three numbers, 3, 4, and 8. We will start by asking if 3 goes here.

We can see with the available surrounding data that 3, in fact, could go anywhere.

So let’s forget about 3 for a moment and see if 4 will fit our slot.

We have much better luck with finding 4. As you can see, we already found that in these 3 available slots, 4 only goes in one particular slot.

In fact, these two rows alone tell us there is only one true slot. And since we must have a 4 in the square, these two rows give us sufficient information to place the 4 in this slot. This allows us to speed up the process by knowing the facts and principles of the situation.

Even though we solved for 4, we’re still not positive where 3 properly fits.

So let us continue on and see if 8 will fill our slot.

8 is actually already in our row at this location therefore…

8 must go in the other slot.

That only leaves 3 to go in our final slot!

Every row, column, and 3 by 3 square MUST HAVE 1 through 9. This is also the puzzle’s downfall. Through proper elimination we can solve with 100% accuracy.
Any rule breaking or incomplete puzzles was most likely due to an error of elimination. Yes, sometimes even master puzzle solvers put an extra number in a row or column once in a while. Always remember to double check your puzzles!
Sudoku puzzle misprints are generally rare, but they do happen and are often obvious from the start once you’ve mastered the game.
Now that we worked halfway through, go ahead and solve the entire puzzle.

Solved!!

Sudoku Level 2 Puzzle

Let’s ramp it up again with a simulated level 2.

Were going to make the same approach and assess the puzzle.

Let’s start here and learn a new technique.

The answer is 3! Again, let’s work backwards.

Let’s start by finding where 3 already exists.

We can see that we have two slots to choose from.

Let’s focus our attention on the blue square for moment. It needs 4, 7, and a 3 as well. We can also see that there is only one available slot for a 3 in this square. Let’s go ahead and fill that slot.

Now that we have more data available, we see clearly now that a 3 is only able to fit in the red slot.

Now you try! See if you can deduce what number goes in the red slot. Solve the blue square by using the surrounding squares to find you answer.

Remember to see what numbers are missing and use your elimination methods!
Awesome! Now go ahead and solve this puzzle.

Now let’s take it a step further.

Sudoku Level 3 Puzzle

This is a simulated level 3 puzzle.
We will need to enhance our skills to be able to complete this level. We are going to see how every number, 1 through 9, satisfies three criteria each time it is placed. And how knowing which criteria is satisfied and which is not, can be quite useful to us.

Take a look at the blue square. We will be finding where 7 fits using the available data.

When we cross out the rows and columns that already have 7 in them, we see the red square has two open slots available in the SAME column.

This red square is missing a 7 as well as the red column. When 7 is placed in one of these slots of the red column, both the square and the column will be satisfied. However without more information we do not know which row will be satisfied along with this criteria. Therefore we cannot place 7 with certainty.

Although we don’t know which row 7 goes in, we know that for the red square, the 7 must go somewhere within the red column.

And therefore, that COLUMN’S criteria is now satisfied which leaves us one slot for 7 in the blue square.

When we expand our view and identify satisfied criteria, we can formulate other accurate answers that will lead to the entire puzzle being solved.

Let’s solve for 5 in this column. Let us examine the squares it passes through.

As we can see, two of these three squares already have 5 in them.

Therefore satisfying the squares and leaving us one slot for 5 to satisfy the column.

By placing 5 in this slot we have satisfied this column, square, and row. Let’s see if we can find all the 5’s for this puzzle. Start looking for clear answers, and then move on to this new elimination technique.

We can see that two of our squares in red have only one slot available for 5.

That leaves us with only one square (in red) that is missing a 5 in this puzzle and one slot for 5 to fit. We also see that every square, row, and column has a 5. We have solved all the 5’s for this puzzle.

Take a look at the red slot. Using ONLY the information from the blue square and the blue intersecting row and column, solve the number for this slot.

In the red slots we see 1 through 8. This leaves 9 to go in our slot because it is the only number that satisfies all three criteria. This is the final technique we will be learning.
By eliminating everything that will not fit, we find that we are left with one number with no objections and that meets all three criteria.

Go ahead and combine all your new Sudoku skills and solve the puzzle.

Amazing! Now for the biggest test of all….

Solving a Level 4 Sudoku Puzzle

Now it’s time for the big and bad level 4 Sudoku!
This is the original puzzle from the beginning. This particular puzzle is extremely challenging even for a level 4 puzzle.
If you can use everything you have learned through these instructions, you can solve this puzzle! This will take a little time to complete.
Starting out, you will find the level 1 and 2 puzzles will be fun to complete with a few challenges. Level 3 and 4 puzzles provide lots of challenges and will take some time, thought, and a broad look at the puzzle to solve.
If you can solve this puzzle, you can solve any puzzle at any level!
Remember to pass on the fun and share the game!