Easy Irregular Diagonal Sudoku

Jigsaw regions plus two diagonal constraints — every digit 1–9 must appear once in each row, column, region, and diagonal. Free to play.

Easy Medium Hard Expert

New to Irregular Diagonal Sudoku? Jigsaw regions replace the boxes, and both main diagonals must also hold 1–9 each. Start here.

3
4
1
5
7
6
5
9
2
3
8
6
1
7
4
5
3
6
9
7
7
3
5
1
4
3
2
1
7
2
3
7
6
7
4
8
3
2
Mistakes
0/3
Score
-
Time
00:00
Try Medium Irregular Diagonal Sudoku →
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What is Irregular Diagonal Sudoku?

Difficulty
★★★★☆
4/5
Constraint Type
Combined: Irregular + Diagonal
Typical Givens
22–30
Avg. Solve (Easy)
8 min

Solving Techniques for Easy Level

Technique Description Level
Map All 29 Units First You have 9 rows + 9 columns + 9 irregular regions + 2 diagonals = 29 constraint units. Identify all irregular regions and both diagonals before starting. Beginner

Ready to go deeper? Try Medium Irregular Diagonal Sudoku to unlock Intermediate techniques.

Techniques to Master at Easy

  • Last Free Cell technique — You have 29 houses — 9 rows, 9 columns, 9 jigsaw regions, 2 diagonals — so somewhere a unit is always one cell from finished; rotate your scan through all four house types.
  • Last Possible Number technique — A diagonal cell inside a snaking region answers to four houses at once — exhaustive elimination on those cells routinely leaves a single candidate.

Average Solve Time by Difficulty

Easy
8 min
Medium
18 min
Hard
35 min
Expert
65 min
Want a full walkthrough of rules, strategies, and solving steps? How to Play Irregular Diagonal Sudoku →

Related Variants

Diagonal Sudoku

Isolates the diagonal half of this variant — practise the two extra houses on a familiar 3×3 box layout.

Jigsaw Sudoku

Isolates the jigsaw half — pure region-shape reading without the diagonal bookkeeping.

Chaos Construction

If 29 visible houses feel comfortable, try deducing the nine jigsaw regions yourself as part of the solve.

Frequently Asked Questions — Easy Irregular Diagonal Sudoku

What is Irregular Diagonal Sudoku?
Irregular Diagonal Sudoku combines two variant rules at once. Like Jigsaw Sudoku, it replaces the standard 3×3 boxes with nine irregularly shaped coloured regions. Like Diagonal Sudoku, both main diagonals (top-left to bottom-right, and top-right to bottom-left) must also contain each of the digits 1–9 exactly once.
How many constraints does Irregular Diagonal Sudoku have?
Each puzzle enforces four types of uniqueness: rows (nine of them), columns (nine), irregular regions (nine jigsaw shapes), and both main diagonals (two). That is 20 separate constraint groups — compared to 27 in standard Sudoku — but the diagonal and region constraints are stronger because they cross the others at unexpected angles.
Which cells are on the main diagonals?
The main diagonal runs from the top-left cell (row 1, column 1) through the centre (row 5, column 5) to the bottom-right (row 9, column 9). The anti-diagonal runs from top-right (row 1, column 9) through centre to bottom-left (row 9, column 1). Nine cells are on each diagonal, and the centre cell (row 5, column 5) sits on both.
How do I start an easy Irregular Diagonal Sudoku?
Begin by scanning the two diagonals — they provide strong early constraints. If several digits are already placed on a diagonal, the remaining cells on that diagonal narrow down fast. Then apply standard row and column scanning, and finally use the region shapes to place any remaining obvious digits.
Is Irregular Diagonal Sudoku harder than regular Diagonal Sudoku?
Yes, because the jigsaw regions interact with the diagonals in complex ways. In regular Diagonal Sudoku the box shapes are fixed and predictable; here the regions cut across the diagonals at irregular angles, making it harder to spot eliminations at a glance. Easy puzzles are designed to be approachable for newcomers to the combined variant.

More questions? See the full Irregular Diagonal Sudoku guide.