Notes on this puzzle
38 digits are printed in this grid and the other 43 cells are yours to fill. A solver that never guesses gets through it in 43 steps.
Nothing beyond hidden single is needed anywhere, so the whole grid is a scanning exercise.
Among the givens, 1 is the most common digit (5 times) and 4 the rarest (3). The emptiest box is the central one, with 2 givens; the top-left box is the most crowded, with 7.
Where to beginLook at row 1, column 2 first: a hidden single is available there from the very start. Scan digit by digit; notes are hardly needed here.