Medium 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

Irregular Diagonal Sudoku at medium difficulty. Diagonals interact with jigsaw regions across multiple rows — expect powerful intersection deductions.

3
9
8
3
6
2
1
8
4
5
3
8
1
6
2
9
7
4
9
1
6
8
3
5
2
9
6
3
5
9
2
3
Mistakes
0/3
Score
-
Time
00:00
Try Hard Irregular Diagonal Sudoku →
Progress0%

What is Irregular Diagonal Sudoku?

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

Solving Techniques for Medium 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
Diagonal–Region Intersection Cells on a diagonal that also sit in the same irregular region create a powerful two-unit intersection — use both constraints simultaneously. Intermediate
Diagonal Pointing Pairs If a digit on a diagonal is confined to one irregular region, eliminate it from all other cells of that region. Intermediate

Master these, then take on Hard Irregular Diagonal Sudoku to learn Advanced techniques.

Techniques to Master at Medium

  • Hidden Singles technique — Scan the two diagonals as houses alongside the jigsaw regions: a digit confined to one diagonal cell places immediately, and each placement echoes through up to four other houses.
  • Obvious Pairs technique — A pair on a diagonal eliminates along the diagonal AND inside each pair cell's jigsaw region — in this combined variant, every pair clears more cells than in either parent variant.

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 — Medium Irregular Diagonal Sudoku

What techniques are most useful for medium Irregular Diagonal Sudoku?
Medium puzzles reward diagonal-first solving combined with region scanning. Start by filling in obvious diagonal singles, then look for hidden singles in each region. Pay particular attention to cells that sit on both a diagonal and a region border — they carry the most constraints and break open the puzzle fastest.
How do the diagonals interact with irregular regions?
Because regions are jigsaw-shaped, a single diagonal may pass through four or five different regions. Each intersection creates a two-way constraint: the digit on the diagonal eliminates it from the region, and the region's candidates limit what can go on the diagonal. Tracking these cross-constraints is the core skill at medium difficulty.
What is a diagonal pointing pair in this variant?
A diagonal pointing pair occurs when a digit can only appear in two cells of an irregular region, and both those cells happen to lie on the same diagonal. This eliminates the digit from all other cells on that diagonal — a very powerful deduction unique to this combined variant.
Can digits repeat on the diagonals?
No. Each main diagonal must contain each of the digits 1–9 exactly once, just like a row or column. This is what makes the diagonal a constraint you can actively use — not just a decoration — and it is the key rule to exploit when you feel stuck.
How long does a medium Irregular Diagonal Sudoku take?
Most players finish medium puzzles in 20–35 minutes. The extra diagonal constraints actually help as much as they hinder — they often provide the single crucial elimination that unlocks a stubborn area. Give the diagonals priority whenever you stall on region or row/column logic.

More questions? See the full Irregular Diagonal Sudoku guide.