Free Printable Diagonal Sudoku (Sudoku X) and Variant Puzzles, Each Checked for a Unique Solution

10 free puzzles from the book are below. Print this page to solve them on paper. The solutions are further down.

The book includes all its puzzles, all solutions and the solver source (solver.py).

Rules

The rule of each variant also appears under every puzzle of that variant.

Sudoku X (also called diagonal sudoku). Fill every row, column and 3x3 box with the digits 1 to 9. Both main diagonals (shaded grey) must also hold 1 to 9 once each.

10 free puzzles

X-01: Sudoku X

7			6			1
4		9	8	3	1		2
			7	2
	4	6						1
	7	3		1	4
1	9	5			2
	2			9
			1		7	6
			2	5	3

Rule: Fill every row, column and 3x3 box with the digits 1 to 9. Both main diagonals (shaded grey) must also hold 1 to 9 once each.

X-02: Sudoku X

	5			8		7
7	4		3	5		8
		9		6	4	3		2
6				1				5
2		5		7			8
					5
4			5	2	3			9
		7			6
					7	2

Rule: Fill every row, column and 3x3 box with the digits 1 to 9. Both main diagonals (shaded grey) must also hold 1 to 9 once each.

X-03: Sudoku X

1		7			6	3
		6	3	4		9		1
9			7		1		6	5
		5				6	3
		9		5	3			4
6	3		1	7	4
	9	4
						2		8

Rule: Fill every row, column and 3x3 box with the digits 1 to 9. Both main diagonals (shaded grey) must also hold 1 to 9 once each.

X-04: Sudoku X

		1		8	9	2		7
7			4
				3
1		3	9		5		6
			7			4	1
6								9
		2	6	5			9
		7		9	4			3
		6	3	7				1

Rule: Fill every row, column and 3x3 box with the digits 1 to 9. Both main diagonals (shaded grey) must also hold 1 to 9 once each.

X-05: Sudoku X

	8				1	5	2
9					7
1	6		3			9
8		7	6					2
	4			1		8		7
						1
4	9	8		7
3			4	8	6	7
	7							4

Rule: Fill every row, column and 3x3 box with the digits 1 to 9. Both main diagonals (shaded grey) must also hold 1 to 9 once each.

X-06: Sudoku X

			7				3
						5		8
3		8	6		5
					4		5	6
		5	9		6	2	1
1	4	6			7
2
5			4		9			1
	1	4		6	3		9

Rule: Fill every row, column and 3x3 box with the digits 1 to 9. Both main diagonals (shaded grey) must also hold 1 to 9 once each.

X-07: Sudoku X

7			2			6		9
		3	7		9		8	2
2				6		3	7	1
3			6
		4						6
				4				7
9						1
5		1		9		7	4
			1			9		3

Rule: Fill every row, column and 3x3 box with the digits 1 to 9. Both main diagonals (shaded grey) must also hold 1 to 9 once each.

X-08: Sudoku X

1	6	8						7
			6		5
				7	8	2
			2				1	4
				5	7
	2		4			9		5
7	8	1	5		4	3
	9			3	1
		4			9		5

Rule: Fill every row, column and 3x3 box with the digits 1 to 9. Both main diagonals (shaded grey) must also hold 1 to 9 once each.

X-09: Sudoku X

	9
				3		6
2				8		1	3
4		6			8	9
	1	5	4	9
		9	6					3
	4		8			3
	5	8					2
3	6		9		4	8		1

Rule: Fill every row, column and 3x3 box with the digits 1 to 9. Both main diagonals (shaded grey) must also hold 1 to 9 once each.

X-10: Sudoku X

	2		8			4		6
	5	8	7	6			2
3						9
	3	9		7	1	8	6
			6	3		5	9
	6
6				5
2	8		9			6
			2				3

Rule: Fill every row, column and 3x3 box with the digits 1 to 9. Both main diagonals (shaded grey) must also hold 1 to 9 once each.

Solutions

X-01: Sudoku X

7	3	2	6	4	5	1	8	9
4	6	9	8	3	1	7	2	5
5	1	8	7	2	9	4	6	3
2	4	6	9	7	8	3	5	1
8	7	3	5	1	4	2	9	6
1	9	5	3	6	2	8	4	7
3	2	7	4	9	6	5	1	8
9	5	4	1	8	7	6	3	2
6	8	1	2	5	3	9	7	4

X-02: Sudoku X

3	5	2	9	8	1	7	6	4
7	4	6	3	5	2	8	9	1
8	1	9	7	6	4	3	5	2
6	7	4	2	1	8	9	3	5
2	3	5	4	7	9	1	8	6
1	9	8	6	3	5	4	2	7
4	8	1	5	2	3	6	7	9
9	2	7	8	4	6	5	1	3
5	6	3	1	9	7	2	4	8

X-03: Sudoku X

1	5	7	8	9	6	3	4	2
2	8	6	3	4	5	9	7	1
9	4	3	7	2	1	8	6	5
4	1	5	2	8	9	6	3	7
7	2	9	6	5	3	1	8	4
6	3	8	1	7	4	5	2	9
8	9	4	5	6	2	7	1	3
5	6	1	4	3	7	2	9	8
3	7	2	9	1	8	4	5	6

X-04: Sudoku X

3	6	1	5	8	9	2	4	7
7	5	9	4	2	6	1	3	8
2	8	4	1	3	7	9	5	6
1	7	3	9	4	5	8	6	2
9	2	8	7	6	3	4	1	5
6	4	5	8	1	2	3	7	9
8	3	2	6	5	1	7	9	4
5	1	7	2	9	4	6	8	3
4	9	6	3	7	8	5	2	1

X-05: Sudoku X

7	8	4	9	6	1	5	2	3
9	5	3	8	2	7	6	4	1
1	6	2	3	5	4	9	7	8
8	1	7	6	9	5	4	3	2
5	4	9	2	1	3	8	6	7
2	3	6	7	4	8	1	5	9
4	9	8	5	7	2	3	1	6
3	2	1	4	8	6	7	9	5
6	7	5	1	3	9	2	8	4

X-06: Sudoku X

6	5	1	7	4	8	9	3	2
4	9	7	3	1	2	5	6	8
3	2	8	6	9	5	1	4	7
9	3	2	1	8	4	7	5	6
8	7	5	9	3	6	2	1	4
1	4	6	5	2	7	3	8	9
2	6	9	8	5	1	4	7	3
5	8	3	4	7	9	6	2	1
7	1	4	2	6	3	8	9	5

X-07: Sudoku X

7	1	8	2	3	4	6	5	9
6	5	3	7	1	9	4	8	2
2	4	9	8	6	5	3	7	1
3	2	5	6	7	1	8	9	4
8	7	4	9	2	3	5	1	6
1	9	6	5	4	8	2	3	7
9	3	7	4	8	6	1	2	5
5	6	1	3	9	2	7	4	8
4	8	2	1	5	7	9	6	3

X-08: Sudoku X

1	6	8	3	4	2	5	9	7
3	7	2	6	9	5	4	8	1
5	4	9	1	7	8	2	6	3
9	5	7	2	8	3	6	1	4
4	1	6	9	5	7	8	3	2
8	2	3	4	1	6	9	7	5
7	8	1	5	6	4	3	2	9
2	9	5	8	3	1	7	4	6
6	3	4	7	2	9	1	5	8

X-09: Sudoku X

6	9	3	1	4	7	5	8	2
5	8	1	2	3	9	6	4	7
2	7	4	5	8	6	1	3	9
4	3	6	7	2	8	9	1	5
7	1	5	4	9	3	2	6	8
8	2	9	6	1	5	4	7	3
1	4	7	8	5	2	3	9	6
9	5	8	3	6	1	7	2	4
3	6	2	9	7	4	8	5	1

X-10: Sudoku X

7	2	1	8	9	3	4	5	6
9	5	8	7	6	4	1	2	3
3	4	6	1	2	5	9	8	7
5	3	9	4	7	1	8	6	2
8	7	4	6	3	2	5	9	1
1	6	2	5	8	9	3	7	4
6	1	7	3	5	8	2	4	9
2	8	3	9	4	7	6	1	5
4	9	5	2	1	6	7	3	8

How uniqueness was checked

A puzzle is unique when exactly one filling satisfies it. For each puzzle, the solver script (solver.py) searches the fillings allowed by that variant's rules and stops once it finds a second solution or has exhausted the search. Checked by an exhaustive solver script: exactly one solution found per puzzle.

You can repeat the check yourself, because the book includes the solver source (Python 3, standard library only). The solver source is released under the MIT License.

The book

A PDF with variant sudoku puzzles for USD 5, plus all solutions and the solver source. The PDF is for personal use: print it for yourself, no resale or redistribution.