Naked Pairs

The Single Candidate and Single Position techniques will take you a long way when solving Sudoku, but there are more techniques you need to learn for the hard Sudoku puzzles.

Let's have a look at Naked Pairs!

This is a partially-completed Sudoku - we have reached this point just using Single Candidate and Single Position, but we can't go any further with these techniques.

The two highlighted cells contain a 5 and a 7, we don't know yet which way round they will appear, but we do know they will appear in these 2 cells.

They could appear like this.

If they do, there can't be another 5 that appears in the same row (and column and region), i.e. we would remove the highlighted 5 pencil mark.

Or, they could appear like this.

Again, there can't be another 5 that appears in the same row (and column and region), i.e. we would remove the highlighted 5 pencil mark.

It doesn't matter which way round the 5 and 7 appear in the 2 cells, we know that we can't insert a 5 in the highlighted cell.

This means we can remove the 5 as a candidate for this cell, i.e. we can remove the 5 pencil mark.

This only leaves one candidate for this cell, i.e. the value 1. The naked pairs technique has allowed us to move forward on this Sudoku puzzle.

When looking for Naked Pairs, you are looking for 2 values that appear by themselves in 2 cells within the same row/column/region.

Here is another example of a Naked Pair in a row - the highlighted 6 and 9 are naked pairs, which means we can remove all other instances of 6 and 9 from this row.

Naked Pairs can appear in rows, columns, or 3x3 regions.

This is an example of a Naked Pair in a column - the highlighted 8 and 9 are a Naked Pair, which means we can remove all other instances of 8 and 9 from this column.

Naked Pairs can also appear in a 3x3 region.

In this example, the 5 and 9 are Naked Pairs within the central 3x3 region. We can remove the 5 from other cells in this region.

(You might also have noticed that these are also Naked Pairs in this column - we can remove the 5 and 9 from the bottom cell in the same column).

Can you spot the Naked Pair in this column?

Did you spot this Naked Pair?

Can you spot the Naked Pair in this row?

These Naked Pairs aren't in the same region like our previous example.

That doesn't matter, they are in the same row, so they are a valid Naked Pair.

Can you spot the Naked Pairs in this region?

Plenty of pencil marks we can remove here!

Can you spot the Naked Pairs in this grid?

There is more than one pair to find!

Did you spot these Naked Pairs?

How about these?

Can you spot the Naked Pairs in this grid?

There is more than one pair to find!

Did you spot these Naked Pairs?

How about these?

That's everything you need to know about Naked Pairs!

You are looking for the same 2 values that appear in 2 cells within the same row, column or region. You don't often see that many cells with only 2 pencil marks in them, so they can be quite easy to spot.

The next technique is Hidden Pairs.

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Naked pairs

Naked Pairs

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