Techniques / Singles
Naked Single
A cell with only one candidate left.
Look at one empty cell and cross out every digit that already appears in its row, column or box. If exactly one digit remains, that digit goes in the cell.
It is called "naked" because the single candidate is visible without looking at any other cell. With pencil marks turned on, these are the cells showing just one small digit.
Notation
Naked Single: 3 goes in r4c3.
placed
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