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Sudoku set

9x9 Medium Sudoku Puzzles - Fun and Challenging

Sudoku Puzzles — 9x9 medium Set 1. Fun and challenging. Hours of entertainment.

9x9 medium sudoku Set 1 designed to be fun and challenging.

Sudoku play tools

  • Pencil marks
  • Grid state
  • Candidate digits
  • Elapsed time
  • Completion state

Variant rule

  • Rows, columns, and boxes contain every digit once.
  • One valid solution
  • Variant constraint validator
  • Visible rule support
  • Rows, columns, boxes

Windoku — Free Online & Printable

Windoku, also known as Window Sudoku or NRC Sudoku, adds four fixed 3×3 window regions to the standard 9×9 grid. The windows are positioned symmetrically: top-left at rows 2-4, columns 2-4; top-right at rows 2-4, columns 6-8; bottom-left at rows 6-8, columns 2-4; bottom-right at rows 6-8, columns 6-8. Every window must contain digits 1-9 without repetition, in addition to standard row, column, and box constraints. The overlapping nature of windows and standard boxes creates rich constraint chains that experienced solvers find deeply satisfying.

About the 9×9 Grid

The 9×9 grid is the full standard size for all sudoku variants. With 81 cells in 3×3 boxes, a 9×9 variant puzzle takes 10 to 60+ minutes depending on difficulty level and variant type. All variant rules reach their full expressive potential at this size: Killer cages create complex arithmetic networks, Jigsaw regions form visually distinctive shapes, and diagonal constraints span the entire grid. The 9×9 is where experienced solvers spend most of their time, and where the depth and elegance of each variant rule is fully revealed.

Medium Difficulty

Medium difficulty requires applying variant rules in combination with standard sudoku techniques. You will need hidden singles (where a number can only go in one cell within a region, even if multiple numbers are possible for that cell) and basic elimination chains. For Killer Medium, expect some cage combinations where two or more possible sets remain and must be narrowed by row and column logic. Average time: 10-20 minutes for 9×9. Candidate notation is helpful but not essential. This is the recommended starting difficulty for players familiar with standard sudoku.

How to Get Started

  1. Choose "New Puzzle" to generate a fresh Windoku puzzle with a unique solution
  2. Click or tap cells to enter numbers (1–9)
  3. Use the constraint highlights to track which numbers are still available
  4. Print the puzzle if you prefer solving on paper

How to use this printable Sudoku set

Best for logic practice, print-and-solve puzzle books, classroom challenges, and variant Sudoku exploration.

  • Print the grid, solve with notes, then reveal or compare answers only after a full solving attempt.
  • Start with classic Sudoku, then branch into X, Hyper, Jigsaw, Killer, and other rule variants.
  • Use the previous and next set links to stay inside the same page family before jumping to broader hubs.

Answer key policy

Answer support is available for review after a real attempt; printable answer-key behavior depends on the activity type.

Same-family next steps

Use the previous and next set links to stay inside the same page family before jumping to broader hubs.

Measurement events

This page should measure landed, started, used hint, checked answer, completed, printed/downloaded, shared, and clicked next events when the matching controls exist.

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