Hidden Pairs

Have a look at this grid, the third column is missing the values 2 and 6.

Both values only appear in the pencil marks for the highlighted cells. This means that there are only 2 ways we can insert 2 and 6 in this column.

We can insert them this way round.

Or, we can insert them this way round.

There are no other options for inserting 2 and 6 in this column, we just don't know at the moment which way round will be the solution.

This means we can remove all other pencil marks from these 2 cells.

We can remove the pencil marks 1, 3 and 5 from the top cell.

And we can remove the pencil mark 3 from the bottom cell.

This leaves us with this.

In this row, the values 6 and 8 can only appear in the highlighted cells.

We don't know which cell contains the 6, and which contains the 8, but we do know that they must be in these 2 cells.

This means we can remove all other pencil marks from these 2 cells.

To leave us with this!

In this region, the values 2 and 4 can only appear in the highlighted cells.

We don't know which cell contains the 2, and which contains the 4, but we do know that they must be in these 2 cells.

This means we can remove all other pencil marks from these 2 cells.

To leave us with this!

Can you spot the hidden pairs in this row?

Did you spot this hidden pair?

Can you spot the hidden pairs in this row?

Did you spot this hidden pair?

Can you spot the hidden pairs in this region?

Did you spot this hidden pair?

The interesting thing about hidden pairs is that after removing the pencil marks, you are always left with a naked pair. In this instance we would also be able to remove the other 9 candidate in the same column.

There are plenty of ways to move forward with this puzzle, but there is at least one set of hidden pairs in this Sudoku.

Can you spot them?

There is also a naked pair in this row, but we were looking for the hidden pair.

Did you spot them?

That's everything you need to know about hidden pairs!

Naked pairs are much easier to spot, so you should always look for them first.

After applying the Hidden Pair technique, you are quite often left with a Naked Pair.

Practice puzzles

Here are 10 Sudoku puzzles where you will need to apply the Hidden Pairs technique to solve,

Sudoku Academy

Hidden pairs

Hidden Pairs

Practice puzzles

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