Large print sudoku: hard

Solving tips

Start with the digit that already appears most often and look for the one cell in each box where it can go. When a cell is down to two or three possible digits, pencil them small in a corner. Triples and the X-wing.

What makes these hard

Hard puzzles need either a triple or an X-wing. A triple is a bigger pair: three cells in one unit that, between them, can only hold the same three digits, so those digits are spoken for in that unit. They are harder to see because each cell may show only two of the three.

An X-wing looks at one digit across two rows. If in each of two rows a digit can only go in the same two columns, then whichever way it falls, those two columns get their copies from these two rows, so the digit can be crossed off everywhere else in those columns. The same works with columns and rows swapped. Full pencil marks for the digit in question make it much easier to spot.

Where to start on puzzle 1

These are the first moves the easiest-first method finds in puzzle 1, the same steps the hint button in Sprout Sudoku would give you:

1. Naked single. Row 3, column 5 can only be a 4: its row, column and box already hold every other digit.
2. Naked single. Row 9, column 4 can only be a 6: its row, column and box already hold every other digit.
3. Naked single. Row 9, column 6 can only be a 4: its row, column and box already hold every other digit.

Stuck? The key step in each puzzle

Each puzzle below has one moment where the easy steps run out and the hard technique is needed. The digit count tells you roughly where it comes: if your grid has about that many digits filled and nothing else fits, this is the step to look for. It is written out in full, so read it only when you want the help.

Show the key steps

• Puzzle 1, with 42 of 81 digits filled (X-wing): X-wing on 9: in rows 1 and 5, the 9 fits only in columns 1 and 9. Each of those rows puts its 9 in one of those columns, so no other cell in columns 1 and 9 can be a 9.
• Puzzle 2, with 42 of 81 digits filled (Naked triple): In the center box, row 4, column 6; row 6, column 4; and row 6, column 5 hold only 6, 7 and 9 between them. Those three cells take all three digits, so no other cell in the center box can be 6, 7 or 9.
• Puzzle 3, with 49 of 81 digits filled (X-wing): X-wing on 2: in rows 6 and 9, the 2 fits only in columns 2 and 7. Each of those rows puts its 2 in one of those columns, so no other cell in columns 2 and 7 can be a 2.
• Puzzle 4, with 43 of 81 digits filled (Naked triple): In the center box, row 5, column 4; row 5, column 5; and row 6, column 4 hold only 5, 7 and 8 between them. Those three cells take all three digits, so no other cell in the center box can be 5, 7 or 8.
• Puzzle 5, with 57 of 81 digits filled (X-wing): X-wing on 5: in rows 3 and 7, the 5 fits only in columns 1 and 9. Each of those rows puts its 5 in one of those columns, so no other cell in columns 1 and 9 can be a 5.
• Puzzle 6, with 38 of 81 digits filled (X-wing): X-wing on 6: in rows 2 and 7, the 6 fits only in columns 4 and 9. Each of those rows puts its 6 in one of those columns, so no other cell in columns 4 and 9 can be a 6.

Prefer a screen? Sprout Sudoku is the same kind of puzzle to play free in your browser, with hints and saved progress.

More printable puzzles

• Large print sudoku: easy
• Large print sudoku: medium
• Large print sudoku: expert
• Large print winter word search
• All free printable puzzles