The methods included in the "Easy" category extend the ideas of Naked Singles and Hidden Singles
into Naked Pairs, Naked Triples, Hidden Pairs and Hidden Triples. The pairs
and triples are fairly common in various sudoku boards, although much more rare than the singles (as is any other method). In order to easily
spot the pairs and triples, we would recommend using the candidates options in our Sudoku. If you do not wish to spend the time to fill in all candidates,
our sudoku has a button which will automatically calculate them for you.
There is an important difference between pairs and triples, which may not be obvious at first. This difference is present in other more advanced strategies, such as Swordfish and Jellyfish (which are extensions of X-Wing).
In our Sudoku Board Generation and grader, an "Easy" board is one, which contains only Naked and Hidden singles, pairs and triples. What is more, we make sure that there is a fair number of pairs and triples. If a board only contains one or two of these "Easy" solving methods, we will discard it. Out of all boards in our Sudoku, the number of "Easy" boards is around 3-4%, which is significantly less than the "Very Easy" boards.