Play Sixy Sudoku Online

Sixy Sudoku: The 6×6 Puzzle with Extra Shaded Regions

Looking for a Sudoku variant that packs extra logic into a compact grid? Sixy Sudoku takes the familiar 6×6 grid and adds a twist: three extra shaded 2×3 regions that must also contain the digits 1–6 exactly once. Created by puzzle designer Peter Ritmeester (PZZL.com), Sixy Sudoku brings the concept of Hyper Sudoku's extra regions to a smaller grid. Play our free Sixy Sudoku game above, or read on for rules, strategies, and tips.

🤔 What Is Sixy Sudoku?

Sixy Sudoku is a 6×6 number-placement puzzle inspired by Hyper Sudoku. Like a regular 6×6 Sudoku, it uses a grid divided into six standard 2×3 boxes and the digits 1–6. What makes Sixy unique is the addition of three extra shaded 2×3 regions that overlap with the standard boxes in a zigzag pattern. Each shaded region must also contain the digits 1–6 exactly once — adding a powerful new layer of logic.

The three shaded regions cross the standard box boundaries, meaning some cells belong to both a standard box and a shaded region. This creates extra constraints that make the puzzle more interesting to solve, while the compact grid keeps solving times short.

📋 Rules of Sixy Sudoku

Sixy Sudoku has four simple rules — the first three are shared with standard 6×6 Sudoku, and the fourth is what makes Sixy special:

1. Each row must contain the digits 1, 2, 3, 4, 5, and 6 exactly once.
2. Each column must contain the digits 1, 2, 3, 4, 5, and 6 exactly once.
3. Each standard 2×3 box (outlined by thick lines) must contain the digits 1–6 exactly once.
4. Each shaded 2×3 region (highlighted in purple on the grid) must also contain the digits 1–6 exactly once.

The three shaded regions are arranged in a zigzag pattern that crosses the standard box boundaries. Because the shaded regions overlap with the standard boxes, the same cell may be constrained by its row, column, standard box, and a shaded region — giving you more information to work with.

🎮 How to Play Sixy Sudoku — Step by Step

Here's how to approach any Sixy Sudoku puzzle:

1. Notice the shaded regions — The purple-highlighted cells form three extra 2×3 regions. These are your additional constraints beyond standard 6×6 Sudoku.
2. Scan rows, columns, boxes, and shaded regions — For each empty cell, check which digits are already present in its row, column, standard box, and shaded region (if applicable).
3. Exploit the overlap — Cells inside a shaded region are constrained by four groups (row, column, box, and region), giving you more elimination power than in a standard 6×6 puzzle.
4. Find naked singles — If only one digit is possible in a cell, write it in immediately.
5. Use pencil marks — Click the Notes button to record candidate digits in cells where multiple options remain.
6. Look for hidden singles — If a digit can only go in one cell within a row, column, box, or shaded region, it must go there.
7. Repeat — Each digit you place reduces possibilities elsewhere. Keep scanning until the grid is complete!

⭐ Sixy Sudoku Difficulty Levels

Our Sixy Sudoku offers four difficulty levels, determined by how many of the 36 cells are pre-filled:

• Easy — 20 of 36 cells given. The extra shaded regions make elimination especially effective. Great for learning the variant.
• Medium — 16 of 36 cells given. Requires steady scanning across all four constraint types.
• Hard — 12 of 36 cells given. Relies heavily on pencil marks and systematic deduction across boxes and shaded regions.
• Expert — Only 9 of 36 cells given. Demands advanced technique, exploiting every shaded-region interaction.

🧠 Essential Sixy Sudoku Strategies

Master these techniques to tackle even the hardest Sixy Sudoku puzzles:

1. Region-Box Interaction

Because the shaded regions cross standard box boundaries, they create unique interactions. If a digit within a shaded region can only appear in cells from one standard box, that digit can be eliminated from other cells in that box. This works both ways — box information constrains the region, and region information constrains the box.

2. Cross-Hatching with Four Constraints

Pick a digit and scan across rows, columns, boxes, and shaded regions simultaneously. In Sixy Sudoku, the fourth constraint (shaded regions) often narrows possibilities more dramatically than in standard 6×6 Sudoku.

3. Naked and Hidden Singles

These core Sudoku techniques are even more powerful in Sixy because cells inside shaded regions have four constraint groups instead of three. A cell with four constraints often resolves faster to a naked single.

4. Naked Pairs in Regions

If two cells in the same shaded region share the exact same two candidates, those digits can be eliminated from all other cells in that region. The same applies within rows, columns, and standard boxes.

5. Region-Line Reduction

If a digit within a shaded region must appear in cells that all share the same row or column, that digit can be eliminated from other cells in that row or column outside the region.

📐 Sixy Sudoku vs. Regular 6×6 vs. Hyper Sudoku

All three variants build on the same Sudoku foundation. Here's how they compare:

• Regular 6×6 Sudoku: 6×6 grid, six 2×3 boxes, digits 1–6. Constraints: rows + columns + boxes.
• Sixy Sudoku: Same 6×6 grid and standard boxes, plus three shaded 2×3 regions in a zigzag. Constraints: rows + columns + boxes + shaded regions.
• Hyper Sudoku: 9×9 grid with four extra 3×3 regions. The same "extra shaded regions" concept applied to a full-size grid.

Sixy Sudoku is essentially the 6×6 version of Hyper Sudoku — the same innovation (extra overlapping regions) applied to a smaller grid. If you enjoy Sixy, Hyper Sudoku is a natural next step.

📜 Origin of Sixy Sudoku

Sixy Sudoku was created by Peter Ritmeester, the puzzle designer behind PZZL.com. Ritmeester was already known for his Hyper Sudoku puzzles — a 9×9 variant with four extra 3×3 shaded windows — which he had been designing for the International New York Times for over a decade.

Wondering what would happen if he applied the same "extra gray regions" idea to a smaller grid, Ritmeester developed the Sixy Sudoku concept. The three shaded 2×3 regions — arranged in a zigzag that crosses the standard box boundaries — create a uniquely satisfying puzzle that's quick to play but rich in logic. The name "Sixy" is a playful nod to the six digits used in the puzzle.

💪 Benefits of Playing Sixy Sudoku

Despite its compact size, Sixy Sudoku delivers real cognitive benefits:

• Quick mental workout — Challenging enough to engage your brain, short enough to fit into any break.
• Develops multi-constraint thinking — Juggling four constraint types (row, column, box, region) sharpens analytical skills.
• Builds logical reasoning — Every move requires deduction across overlapping groups.
• Teaches pattern recognition — The shaded regions crossing box boundaries train you to see interactions between constraint groups — a skill that transfers to harder Sudoku variants.
• Bridges to Hyper Sudoku — Master the extra-region concept on a small grid before tackling the 9×9 version.
• Boosts confidence — Completing a non-trivial puzzle with extra constraints delivers a genuine sense of achievement.

🎮 More Sudoku Variants to Explore

Once you've mastered Sixy Sudoku, expand your puzzle repertoire:

• Hyper Sudoku — The 9×9 big sibling of Sixy. Four extra shaded 3×3 regions on a full-size grid.
• 6×6 Sudoku — The same grid size without the extra regions. See how much easier it feels!
• Classic 9×9 Sudoku — The original. Four difficulty levels from Easy to Expert.
• Killer Sudoku — Cage sums add arithmetic to the logic challenge.
• Jigsaw Sudoku — Irregularly shaped regions for a visual twist.