The challenge for Sudoku players is to fill all (1 to 9) numbers in
the box. However, there is a basic rule that is sometimes irritating
for most players who find it hard to complete the box. The rule is: the
number 1 to 9 must come out only once in each row and column.
To avoid being trapped by this rule, players must have strategies
which they can use to solve the puzzle correctly and effectively.
My experience with Sudoku has taught me a few lessons on strategies.
I have have arranged them from the easiest to the most difficult to
help you in your quest.
1. Use a pencil
Pens are for the professional. Though the puzzle may seem to easy,
you will still need to be able to erase any errors when solving the
squares.
2. Think through the answers
Never place any number if you are not sure. Think through your answer and use trial and error as a last resort.
3. Begin with the common numbers
Examine the puzzle to know which of the numbers come out frequently.
Choose of these numbers and know if you can put any of them. As you
begin to try this, draw light lines cutting every row and column that
holds the numbers. Look at each box that does not have the number yet.
If you find the box with a single empty space that is crossed out, put
the number on that space.
4. Go on to the nearly filled box
As you begin putting the numbers, watch out for the rows, columns,
or the 3 x 3 block that are nearly filled in. Once you have found one,
decide which of the numbers should remain to be placed in that box.
Know the numbers that are not yet placed then, check if there is a
suitable position in the box. If there is at least one, place the
number.
5. Start making notes when stuck
The easy numbers have already been placed in. Your eyes are focused
on the page and you realized that you are not using your pencil again.
This means, you are stumped by the puzzle.
Work out the answer for each square again. Make small notes of the
probable answers within each square. Choose a square and record in
small print any of the numbers from 1 to 9 that do not appear in each
row, column or 3 x 3 grid. In this way, you will realize that a square
has a single possible answer only. Place in the number. Then, remove
the possibility from other squares.
6. Search for other options
There will be times that you will have to reach the point where all
the empty boxes have many probable solutions. If this happens, the
puzzle becomes more difficult.
Now, your plan is to look for the several boxes in a row, column or
box that have similar options. For example, if you can locate two boxes
that have same two options, the two numbers should be placed in those
two boxes. It should not be placed somewhere else within the row,
column or box. This should cut down the options in the remaining boxes
to a point where you can answer other else.
This strategy will surely work if the options overlap in two boxes
or more. If the total number of different options along with the
connected group of boxes does not does not go beyond the number of
boxes included, you can presume that each of those numbers is placed
anywhere within that group.
7. Start again if you duplicate
Lastly, if you find an illegal duplicate, stop, and know the reason
behind it. If you still cannot find the reason, it would be better
start the puzzle again.
By following the seven tips
given above, you are most likely to enjoy your game– may it be the easy
or the most difficult Sudoku puzzle.
