Sudoku Solving Strategies

There are two basic sudoku solving strategies that will allow you to find and place correct numbers in empty cells, no matter what level of puzzle you are attempting to solve . These sudoku solving strategies are demonstrated in the sudoku video tutorials you see advertised on this site.

Counting

Counting is the process of counting from 1 to 9 in rows, columns, and regions so that you can tell if there are any missing numbers. The main rule of sudoku: “if a number is right for a cell, this is true for the region and the intersecting row and coloumn” is important here. You don’t count the region, row and coloumn separately. You should start with one cell and then check the presence of numbers 1 through nine for the region and the intersecting row and coloumn.

If you are working harder puzzles the value of one single cell can often be determined by counting in reverse. This is done by scanning the region, the row, and the column for numbers that can not be right for the cell you are investigating. The numbers you don’t eliminate in this process are candidates for this cell.

Cross-hatching

Cross-hatching starts by scanning the rows and columns to look for the presence of a number which blocks cells in the corresponding region. The main rule of sudoku – if a number is right for one cell, this is true for the region, row and coloumn – also applies here. So a number given in any cell, will not occur in any other cells in the same region, row or coloumn.

You repeat the process for all numbers in every row and column. To make things even faster, scan the numbers in their order of frequency. Perform cross-hatching systematically by checking for all the digits from 1 to 9 in order.

Guessing

Guessing is not one of the sudoku solving strategies, at least not until you have progressed to the tough and diabolical puzzles. Guessing the solution to a sudoku puzzle is not only totally unnecessary, but it will lead you up paths that can make the puzzle virtually unsolvable.

Simple logic and a structured approach is all that is required to solve easy and moderate sudoku puzzles. So you will be able to solve easy to moderate puzzles with a minimum of analysis and applying the basic sudoku solving strategies.

Contingencies

Once you become advanced in solving Sudoku Puzzles, you will learn to look for what are called contingencies while you are scanning. Sudoku puzzles that are really challenging might require you to try multiple contingencies. And there will even be times when you have to recognize these contingencies in multiple directions.

But you can solve easy and moderate sudoku puzzles by counting and cross-hatching alone. More challenging sudoku puzzles will need more advanced sudoku solving strategies.