Strategies For Solving Sudoku Puzzles
Sudoku puzzles are very challenging puzzles that require you only follow one rule. You do not have to go out of your way trying to digest any rules unlike other puzzles. With a Sudoku puzzle, you need to remember one rule and one rule only.
Sudoku puzzles are made up of a 9 by 9 grid further divided into 3 by 3 subgrids and a total of 81 cells. The numbers from 1 to 9 are given in some of the cells while the others remain blank. The main objective of the puzzle is to fill in the blank cells with the numbers 1 to 9 in such a way that the columns, rows and even the subgrids contain all the numbers from 1 to 9. Sounds easy? Well, think again. Do not let that simple objective fool you.
So the one rule of Sudoku is: each row, column and subgrid must contain each of the numbers 1 to 9.
Sudoku puzzles can be a challenge to solve. One need not be a mathematician to solve a Sudoku puzzle. The numbers 1 to 9 are just used for convenience. They do not serve any mathematical relationship with the other numbers whatsoever. Their arrangement on the grid is important, not how they might add up. That makes the puzzle more engaging yet at the same time more challenging to complete.
There are several strategies that you can use to solve Sudoku puzzles. These strategies can be summarized into 3 processes.
First is scanning. Scanning is performed at the initial stages of solving the puzzle as well as periodically as you solve the puzzle. Scanning involves 2 basic techniques. One is cross-hatching which is done by scanning rows or columns in order to identify in which cell a particular number belongs. This process is then repeated with the other rows or columns. The other technique is trying to count 1 to 9 in regions, rows and columns in order to identify the missing numbers.
The next strategy of a Sudoku solver is known as marking up. You try to mark possible numbers in each cell by writing them as subscript. The only drawback of this technique is that puzzles printed in newspapers and magazines are usually too small to accommodate even subscript. In this case, you can mark up with a system of dot notation instead.
The last of the 3 main strategies is known as analysing. There are 2 approaches in analysing Sudoku puzzles. One is known as elimination while the other is the “what if” approach. In the elimination approach, progress in solving the puzzle is made by eliminating the candidate numbers from each cell one by one until only one choice is left. After each answer has been achieved, it is necessary to scan to check how the latest number placement affects the remaining blank cells.
In the “what if’ approach, any cell with only 2 remaining number candidates is chosen and a guess is made. The steps used above are repeated unless a repeated number is found. If no repetition or duplication of the selected number is achieved, then it is the most likely answer for that certain cell. This approach may require frequent erasures since guesses are made and may result in several trial and errors before a final answer can be reached.
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