Notes on this puzzle
30 digits are printed in this grid and the other 51 cells are yours to fill. A solver that never guesses gets through it in 58 steps.
Most cells fall to the hidden single move: 47 of the 58 steps. Single candidate accounts for 4 more. The toughest moment needs XY-Wing, and that single step is what sets the level.
Among the givens, 2 is the most common digit (4 times) and 1 the rarest (2). The emptiest box is the top-right one, with 2 givens; the top-left box is the most crowded, with 5.
Where to beginLook at row 8, column 2 first: a hidden single is available there from the very start. Expect a stage where only a pattern across several lines moves the grid on; full notes make it visible.