Notes on this puzzle
32 digits are printed in this grid and the other 49 cells are yours to fill. A solver that never guesses gets through it in 49 steps.
Most cells fall to the hidden single move: 48 of the 49 steps. Single candidate accounts for 1 more.
Among the givens, 4 is the most common digit (6 times) and 9 the rarest (1). The emptiest box is the central one, with 0 givens; the top-middle box is the most crowded, with 5.
Where to beginLook at row 3, column 1 first: a hidden single is available there from the very start. When scanning stalls, look for a cell whose row, column and box together rule out eight digits.