🔥 Hard · 29 given numbers · ID hard-31
Hard Sudoku No. 31
A hard puzzle with exactly one solution. Techniques needed: naked single, hidden single, pointing pair, box/line reduction, naked pair, hidden pair.
The sheet below is exactly what prints on one A4 or Letter page. Choose “Save as PDF” in the print dialog if you prefer a file.
Keyboard: arrow keys to move, 1–9 to fill, Backspace to erase, N to switch notes.
Solution (hidden until you want it)
Stuck, or checking a finished grid? Reveal the answer, or open the printable solution page to keep the answer sheet separate.
Generate a new puzzle
About this puzzle
Hard puzzles require at least one advanced pattern: hidden pairs, naked or hidden triples, X-Wing or XY-Wing. Looking for a different challenge? Easy, Medium or Expert puzzles are on the printable Sudoku page.
Need a break from the numbers?
Try a hard riddle
Sudoku and riddles train the same muscle: spotting what must be true. Here are a few hard riddles with answers.