Here is a puzzle that is solved by hidden singles alone.
{ {1,0,0, 2,0,0, 3,0,0},
{0,2,0, 0,1,0, 0,4,0},
{0,0,3, 0,0,5, 0,0,6},
{7,0,0, 6,0,0, 5,0,0},
{0,5,0, 0,8,0, 0,7,0},
{0,0,8, 0,0,4, 0,0,1},
{8,0,0, 7,0,0, 4,0,0},
{0,3,0, 0,6,0, 0,2,0},
{0,0,9, 0,0,2, 0,0,7}};
I used the following strategy, a candidate 'x' that has only one cell to go and other candidates have legal possibility to occupy that cell, then candidate is said to be the hidden single.
I used this strategy to solve.
1) First pencil up the candidates.
2) Check for naked singles.
3)Update the candidates.
4)Check for hidden singles.
To check for hidden singles, just try if a candidate can occupy more than one cell that row and column, then it is not hidden, else its hidden candidate.