Notes on this puzzle
Sudoku #5204 is a medium grid with 31 givens, which leaves 50 cells waiting for a digit. Played purely by logic, it takes 50 forced steps from the first placement to the last.
Most cells fall to the hidden single move: 48 of the 50 steps. Single candidate accounts for 2 more.
Among the givens, 1 is the most common digit (6 times) and 3 the rarest (2). The emptiest box is the middle-left one, with 2 givens; the top-left box is the most crowded, with 4.
Where to beginLook at row 3, column 4 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.