Rule 1 - Each row should have numbers from 1 to 9, without duplication
The player should focus on completing each line of the grid while making sure there are no duplicate numbers. The order of digitization is not important.
 
Every puzzle, except for the difficulty level, starts with the numbers assigned to the grid. The player must use these numbers as indicators to find out which digits are missing in each line.
Rule 2 - Each column should be numbered from 1 to 9, without duplication
The Sudoku rules for columns in the grid are the same as the line. The player should also complete this with numbers from 1 to 9, making sure that each digit occurs only once in each column.
 
The numbers shared at the beginning of the puzzle serve as indicators to find out which digits are missing in each column and their location.
Rule 3 - Digits can only happen once with a block (nonet)
The standard 9 x 9 grid is divided into 9 small blocks of 3 x 3, also known as nonets. Numbers from 1 to 9 can only happen once nonet.
 
In practice, this means that the process of filling rows and columns without double digits finds within each block an additional limitation in number placement.
Rule 4 - The total value of each row, column, and nonet must be equal to 45
To find out which numbers are missing in each line, column, or block or if there are duplicates, the player can simply calculate or change their mathematical skills and summarize the numbers. If digits appear only once, the total for each row, column and group should be 45.
1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 = 45