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Sudoku set

Free 6x6 Hard Sudoku Puzzles Set 13

Free 6x6 hard sudoku. Hours of entertainment. Get Set 13 now at Free Sudoku Print.

Free 6x6 hard sudoku Set 13. Hours of entertainment.

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

X-Sudoku — Free Online & Printable

X-Sudoku adds a diagonal constraint to the classic sudoku rules. Both main diagonals — running from top-left to bottom-right and from top-right to bottom-left — must each contain the numbers 1 through 9 without repetition. This is the most accessible sudoku variant: the two extra constraints actually make many cells easier to deduce, since numbers on the diagonals are additionally restricted. If you''ve mastered standard sudoku and want a fresh twist without learning complex new rules, X-Sudoku (also called Diagonal Sudoku) is the ideal starting point.

About 6x6 Grid

The 6x6 grid strikes a balance between accessibility and depth. With 36 cells in 2x3 boxes, puzzles take 3 to 10 minutes depending on difficulty. The 6x6 is large enough to showcase variant rules meaningfully — Killer cages have room to create genuine arithmetic puzzles, Windoku windows overlap in interesting ways — while remaining completable in a single sitting. Many players find the 6x6 their "daily driver" format: challenging enough to be satisfying, short enough to fit into a break.

Hard Difficulty

Hard difficulty introduces multi-step deductions where you must track constraint chains across multiple regions simultaneously. Required techniques include naked pairs/triples (two or three cells sharing the same possible values), pointing pairs (where a candidate is confined to one row or column within a region), and intersection removal. For variant-specific techniques: Killer Hard requires cage combination analysis where several possibilities exist and must be eliminated systematically. Average time: 20-40 minutes for 9x9.

How to Get Started

  1. Choose "New Puzzle" to generate a fresh puzzle with a unique solution
  2. Click or tap cells to enter numbers (1-6 for 6x6)
  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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