Aliases are: clue, hint, initial digit
Minimum number of Givens
Currently, there are no known Sudokus with less than 17 givens. For several Sudoku Variations, there are different minimum givens, depending on the number of additional constraints. In the Sukaku variant, there are no givens at all. In this variant, the puzzle is represented by a pencilmark grid, in which no given digits are present.