### Sudoku Tips You Can Use

Play Sudoko

When you are first beginning the hobby of solving Sudoku puzzles you will have moments where you hit a roadblock, meaning you have found a puzzle or level of puzzle which seems unsolvable. Every Sudoku puzzle solver has hit this roadblock. If you reach this roadblock, there are some Sudoku tips which can help you solve almost any Sudoku puzzle. To solve the most advanced puzzles, you would use strategies called X-Wing, XY-Wing and Swordfish. They may sound hard and exotic, but they really are not.

I, like many, like to use the process of elimination to solve Sudoku puzzles. Here is a tip to help with this strategy that you can use; pencil in all possible numbers for each cell, row, column and region. It may look messy but it helps visualize the small solutions which lead to the larger completed puzzle.

00:00

There are Sudoku computer programs which allow you to show all the possible numbers for a cell. Some of the online puzzles also have the option to pencil in the numbers. This allows for a more enjoyable game. The paper varieties and board games don’t have this option; but you can still pencil in the numbers freehand.

Naked Singles :
Every type of Sudoku puzzle will have cells with only one possible number. If there are no other numbers showing, this is called a naked single. Every naked single allows this number to be eliminated from the other cells in the row, column or region where the number is used. The logic being that since this number can only be used once , there are no other positions for it.

# Fig 9

A B C D E F G H I
1

5 3 6     8     9 6     7     9 9 7     9 4     6     8     9 1 2
5

# Fig 10

4     6 7 4     6 9 2 5 3     4     6     8 1 3     4     6     8

# Fig 11

A B C D E F G H I
1 3 5     6 1     4     6     9 7 6     9 2     4     5     6 8 5     9 1     4     6     9
2

In the above example you can also see that once the 9 is placed, the 7,9 solution in the other cell also became a naked single. This is called a hidden single. So named because they are less obvious until another cell is filled, revealing the useable number in the cell. By penciling all of a cell’s possible number solutions, you can find the hidden solutions much easier.

Hidden Singles :
Hidden singles also only have one position they can fill. The added numbers in the cell hide the solution. When there are lots of numbers showing from the surrounding rows, columns and regions a hidden single is hard to find. Hidden singles are common in Sudoku puzzles.

Naked Pairs :
The next tip for solving Sudoku puzzles is to look for the naked pairs. Naked pairs are two identical number combinations in a certain row, column or region. When you find a naked pair, you can eliminate these numbers from all other possible cells for that row, column or region. This combination is also common in puzzles. Here is a naked pair.
Hidden Pairs :
Hidden pairs are, like naked pairs, two numbers that can only work in two cells of a column, row or region. The other numbers in these two cells makes the pair hidden and can be hard to spot. While not as common as naked pairs or singles, hidden pairs do occur often.

Naked Triples :
Another tip in solving Sudoku puzzles is to find the naked triples. Like the name states, these are three numbers which have no other numbers in the same cell. But, unlike naked singles or pairs, a naked triple will not always have all three numbers placed in every cell. Sometimes only two numbers are shown, with the third number being set up by the process of elimination. This is a naked triple.
Hidden Triples :
A hidden triple is harder to spot. The tip about this Sudoku strategy is to look for these in harder puzzles. Hidden triples, like the pairs, have added numbers in the cell which hide the candidates. Hidden triples follow the same rules as a naked triple.

Quads are not as common as the other number combinations. Naked quads are like the other types, where the four numbers are restricted to four cells in a column, row or region. Here is a naked quad.

# Fig 12

5     6     8 1 4     9 3     4     9 2 6     8 7 3     5 3     5     6