Sudoku best practices

There are certainly many strategies to solve a Sudoku. You can find some methods below where it shows how a Sudoku can be solved, step by step. The example here is an easy one. The reason is simply to make it easier to explain the solution of the Sudoku in an understandable way.

Find duplicate numbers

The best way to start a Sudoku is to find a number which already appears quite frequently in the puzzle. In our example, it's the number 6.


Find duplicates


Since each number must occur only once in each row, each column and each block, the few remaining boxes that fit the missing six can be determined. To do so, you mentally fade out all columns, rows and boxes which do not fit the number.We call this method 'scanning'.

Scanning red Scanning green Scanning blue


Another way to find a suitable number in the Sudoku results from the rule that each of the numbers must occur exactly once in every row, every column and every block. Applying this rule let us enter another 1. After entering each number, it is useful to scan all rows and columns in the puzzle again.



Similar to the last step, you can also complete an entire block in the Sudoku. By merely counting-out, we know that in the middle block below a 3 and a 5 are still missing. Since the number 5 can be excluded for one of the remaining empty fields by scanning the corresponding row/column, also number 3 can be written as there is only one more empty field left.