Extra Region Sudoku
A Sudoku variation where extra coloured regions must also contain digits 1 to 9
Extra Region Sudoku is a classic Sudoku variation very close to standard Sudoku, where some extra regions of cells are provided in the grid. These extra regions must also contain unique digits (1–9) with no repetition. This puzzle type was part of the World Sudoku Championship 2015 (WSC 2015), and many puzzles of this type appeared in that championship. This page contains links to all Extra Region Sudoku puzzles and their variations published on this website, including Windoku, Palindrome-Extra Region, Row Sum-Extra Region, and Liar Extra Region puzzles.
Rules of Extra Region Sudoku
Classic Sudoku Rules apply. Additionally, each group of nine coloured cells must also contain the numbers 1 to 9.
Rules of 6×6 Extra Region Sudoku
Mini Classic Sudoku Rules apply. Additionally, each group of six coloured cells must also contain the numbers 1 to 6.
Why Solve Extra Region Sudoku?
- Perfect for transitioning from Classic Sudoku to variations — only one extra rule to learn.
- Features unique extra regions that add a fresh challenge to standard Sudoku solving.
- Includes multiple variations — Windoku, Liar Extra Region, Row Sum-Extra Region, and more.
- Offers 9×9 and 6×6 puzzles — suitable for all skill levels from beginners to experts.
- Was featured in the World Sudoku Championship 2015 (WSC 2015).
- Great for building pattern recognition and advanced Sudoku skills.
Key Techniques for Solving Extra Region Sudoku
- Identify extra regions — locate all coloured groups that must contain unique digits.
- Apply standard Sudoku logic — always apply row, column, and box eliminations first.
- Use extra region constraints — each extra region must have digits 1–9 (or 1–6 for mini).
- Cross-check intersections — a cell belongs to a row, column, box, and an extra region — use all constraints.
- Eliminate candidates — if a digit appears elsewhere in the extra region, eliminate it from other cells.
- Look for singles — in extra regions, if only one cell can take a digit, place it immediately.
🧩 9×9 Extra Region Sudoku Puzzles
🧩 6×6 Extra Region Sudoku Puzzles
🧩 Extra Region Variations
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Frequently Asked Questions
What is Extra Region Sudoku?
Extra Region Sudoku is a variation of Classic Sudoku where additional coloured regions are added to the grid. Each extra region must also contain the digits 1 to 9 (or 1 to 6 in mini puzzles) with no repetition. It was featured in the World Sudoku Championship 2015 (WSC 2015).
What is the difference between Extra Region Sudoku and Windoku?
Windoku is a specific type of Extra Region Sudoku where the extra regions are the four 3×3 windows in the corners. Extra Region Sudoku is a broader category where extra regions can be any shape or position. Windoku is essentially a subset of Extra Region Sudoku with a fixed extra region pattern.
What are the variations of Extra Region Sudoku?
This collection includes several variations: Windoku (4 extra 3×3 corner windows), Palindrome-Extra Region Sudoku (combined with Palindrome Sudoku), Row Sum-Extra Region Sudoku (extra region constraints with row sums), and Liar Extra Region Sudoku (where one clue is false). Each variation adds unique twists to the standard Extra Region Sudoku.
What sizes of Extra Region Sudoku are available?
This collection includes both 9×9 and 6×6 Extra Region Sudoku puzzles. The 6×6 puzzles are perfect for beginners and children learning Sudoku variations, while the 9×9 puzzles offer more challenging puzzles for advanced solvers.
Where can I find more Sudoku variations?
The Sudoku Variations Main Page is the central index for all Sudoku variant types available on Fun With Puzzles. It covers a wide range of constraint-based variants and is the best place to discover new Sudoku challenges.
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