Hey there and welcome to your first steps in sudoku solving. The "Very Easy" category considers
the easiest methods Naked Singles and Hidden Singles. These are commonly referred
to as "eyeballing" methods, i.e. they are very easy to spot and in general you do not need to have the candidates turned on
in order to find them. Although, simple, these methods serve as the basis for other more advanced methods, which will be considered in
the next category. In general, every Sudoku, no matter how complicated, will always be partially solved by a fair amount of
Naked and Hidden Singles.
In our Sudoku Board Generation and grader, a "Very Easy" board is one, which contains only these two methods. Such boards are very common - they represent around 40% of all boards we have generated. We also discard many boards, which we do not like for various reasons. If we only count all the boards which are used, then the Very Easy boards are around 77%.