Sudoku Pro

數獨數獨臨臨

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.

Sudoku Puzzle

How To Play Sudoku Start 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 Sudoku rules. 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

How To Play Sudoku Scan 1s 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).

Applying the Sudoku rule, 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

How To Solve Sudoku Scan 4s 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.