Want To Know How To Play Sudoku?
I will show you how!
My easy to understand illustrated techniques teach you how to play Sudoku puzzles. In several articles, (just too much to show in one article) I will share with you how Sudoku puzzles are solved.
In this article you will learn the basic techniques on how to play Sudoku puzzles and games. When the challenge gets tougher, read my article on
Apply advanced techniques such as X-Wing and Swordfish to break the logjam of the most difficult puzzles.
Sudoku is solvable. A properly prepared puzzle only has one solution. There isn't any need to guess (although you will be tempted at times). Applying simple logic and eliminating candidates will provide the solution in every case.
Math is not required to play Sudoku.
You could play Sudoku using any nine symbols or colors. Numbers just happen to be easier.
Sudoku In a Nutshell
Traditional Sudoku is a 9x9 puzzle grid made up of nine 3x3 regions. Each region, row, and column contains nine cells each. See the example below.
The numbers shown in the example are the "givens". These numbers can not be changed in any puzzle.
You solve the puzzle by filling in the empty cells with a single number (from all the possible candidates) that doesn't violate
There is only one correct number per cell.
Scan the "givens" looking for the same number in different rows, columns, or regions. Eliminate cells for consideration by applying the Sudoku rules using these numbers.
In cases where the solution isn't immediately obvious, you markup or pencil in a vacant cell the possible candidates for future reference.
Consider using the
blank Sudoku grid with candidates
method to determine all the possible candidates. This can save you time in solving puzzles and prevent missing important candidates. It will also reveal answers that are not immediately obvious otherwise.
After you have identified the possible candidates it is time to apply some logic. It is necessary to eliminate all candidates to arrive at a single answer for each cell. I'll cover this topic in more detail in related articles.
The Sudoku Puzzle Challenge
Complete the Sudoku puzzle so that each and every row, column, and region contains the numbers one through nine only once.
The puzzle above I would rate as very easy. I hand crafted this puzzle. It can be solved using simple logic and eliminating a few candidates.
It is interesting to note that it is not the quantity of givens that make a Sudoku puzzle easy or hard. Rather, it is the location and combination of givens.
How To Play Sudoku
Sudoku Puzzle Scan For Ones
In this example on how to play Sudoku, we begin playing Sudoku by scanning the puzzle.
It doesn't matter where you start. I suggest looking for the number that has several "givens". The more givens of a particular number often means that it will be easier to solve.
In this case you can see that there are three number ones (1).
you know that a 1 can not go in any row, column, or region that already has a 1. Plus you know, that every row, column, and region must have a 1.
The scans are marked with red arrows in this example. The two parallel scans from the two ones in the middle tier prevent any ones in the top two rows of the left most region. The vertical scan eliminates the middle cell of the bottom row from consideration.
In this example, you can see that there is only one cell (marked
with a black X) that can contain a 1 in the left most region in the middle tier. Enter a 1 in the cell marked with an X.
Now that a cell is solved, you should look to see if it will help us solve another cell or two. In this case there aren't enough clues to solve for ones at this time.
Likewise there aren't enough clues using this method for twos or threes at this time.
Let's look at the fours for your next lesson on how to play Sudoku.
Sudoku Puzzle Scan For Fours
You can see a similar pattern in the fours as there was in the ones above. In the lower left region you can see that there is only one cell (marked with an X) that isn't eliminated using the scan method. Enter a 4 there.
See if you can find the rest of the fours. You have enough clues.
Now continue solving for fives through eights. Your grid will look like the next graphic in the center of your grid.
Can you find a nine in the example at the left without using any other numbers to help?
Yes, you're right. A nine goes in the middle row to complete the row. It is the only missing number. That was simple!
The Sudoku Solution So Far
You are making great progress in learning how to play Sudoku. You should be able solve most cells using the scan method you learned so far.
The image on the left was solved using just the scan method and entering the naked nine as mentioned earlier.
Pencil In Candidates
Let's say you are stuck. It's time to pencil in all the possible candidates for the remaining cells.
The example on the left shows all the possible candidates for the partially solved puzzle.
You can quickly note that in the seventh column are two "naked" single numbers standing alone.
The naked numbers are 1 and a 2. We also have a "hidden" 6 in the same column.
Since the 1 and 2 are already found, you can eliminate the 1 and 2 from the cell containing 1, 2 and 6. The 6 remains. Enter these numbers and you have quickly completed the column.
Now that you have found a 1 in the seventh column, you can eliminate the 1 from the last cell in the bottom row. (left most region)
A 3 remains. Enter the 3 and you have completed the bottom row.
As you enter a found number, be sure to cross off that number in the row, column, and region that your found number is in. As you do, new "naked" numbers will appear.
In the lower left region, when you entered a 3 solving the bottom row, enables you to now eliminate all threes in this region. Doing so reveals another "naked" 6 and a 1/6 pair. Enter the 6 where the "naked" 6 is.
Now you can also remove the 6 from the last cell in this region. A "naked" 1 remains. Enter the 1 and you have solved this region.
Congratulations! You now know how to play Sudoku (at least an easy one)! Try a harder game of Sudoku now.
Be sure to read my other articles on how to play Sudoku.
More lessons on how to play Sudoku. Read the article Sudoku Tips.
Play Sudoku Dragon
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