15 Types of Sudoku: How to Solve Different Variants
Introduction
Sudoku has become one of the most popular logic puzzles in the world, but what many players don't realize is that you have more than one way to play. Beyond the classic Sudoku puzzle, dozens of Sudoku variations have emerged, each with unique rules, layouts, and levels of challenge.
Some versions of Sudoku keep the familiar 9×9 grid but layer on new rules, add in arithmetic, or use visual imagery to adjust how you solve the puzzle. To help demystify all the differences, this guide walks you through 15 different types of Sudoku, grouped by puzzle style.
Whether you're a beginner learning the Sudoku rules or an advanced solver looking for your next online Sudoku challenge, you'll find a version of Sudoku that matches your interests and skill level. Just use this handy reference or dig deeper in the post for more how-to-play details for each version.
Overview: 15 Types of Sudoku
Here's a quick reference table of all 15 types of Sudoku:
| Type of Sudoku | Grid Style | Unique Twist | Level of Difficulty | |---------------|------------|--------------|---------------------| | Mini | 4×4 or 6×6 | The puzzle uses a smaller grid. | Beginner | | Classic | 9×9 | The grid follows standard Sudoku rules. | Varies from easy to evil | | Super/Giant | 16×16 or larger | This puzzle uses oversized grids. | Advanced | | Jigsaw | 9×9 with odd-shaped regions | 3×3 blocks are replaced with uniquely shaped regions. | Intermediate | | Samurai | Five overlapping 9×9 grids | You must solve multiple grids. | Advanced | | Windoku | 9×9 grid with extra regions | Extra regions must follow standard rules. | Intermediate | | Sudoku X | 9×9 grid with diagonals | Digits must also appear once along diagonals. | Intermediate | | Skyscraper | 9×9 grid with outside clues | Outside numbers show how many skyscrapers are visible from each side. | Advanced | | Killer | 9×9 grid with cages | Digits in a cage must add up to the given total. | Advanced | | Even-Odd | 9×9 grid with shaded cells | Shaded cells are restricted to even/odd numbers | Beginner to Intermediate | | Consecutive | 9×9 grid with marked dots | Adjacent cells must be consecutive digits. | Intermediate | | Greater-Than | 9×9 grid with inequality signs | Cells must respect the inequality clues. | Intermediate | | Arrow | 9×9 grid with arrows | Digits in the arrow must add up to the circle's value. | Advanced | | Wordoku | 9×9 grid with letters | Numbers are replaced with letters. | Beginner to Intermediate | | Color | 9×9 grid with colors | Numbers are replaced with colors. | Beginner to Intermediate |
Key Points
Essential facts about the 15 types of Sudoku:
- Five categories: Classic and Size-Based, Shape and Grid Variants, Rule-Based, Math-Based, Visual Variants
- Difficulty range: From Beginner (Mini, Wordoku) to Advanced (Samurai, Killer, Skyscraper)
- Grid sizes: Range from 4×4 (Mini) to 16×16+ (Super/Giant)
- Unique constraints: Each type adds different rules, arithmetic, or visual elements
- Solving strategies: Each type requires adaptation of basic techniques
- Skill progression: Start with Classic, progress to variants as skills improve
Classic and Size-Based Sudoku
Classic Sudoku is what you typically think of as a normal Sudoku puzzle: a 9×9 grid. But some types of Sudoku are smaller or larger (much larger!) than the standard 9×9. However, these size-based versions all follow the standard Sudoku rules where each row, column, and 3×3 block contains the digits 1 through 9 without repeats.
The classic version makes a great entry point for Sudoku. After you gain confidence working normal Sudoku puzzles, you can move on to puzzles that layer more constraints, add more rules, or change the rules completely.
1. Mini Sudoku
Mini Sudoku makes for a great entry-level Sudoku puzzle for kids. The grid is only 4×4 or 6×6 and comes in easy and hard varieties. It follows the same Sudoku rules but you only use numbers 1 through 4 or 1 through 6, depending on the size of the grid.
Grid Style: 4×4 or 6×6
Unique Twist: Smaller grid size with fewer numbers (1-4 for 4×4, 1-6 for 6×6)
Difficulty Level: Beginner
How to Solve:
- Same rules apply: Each row, column, and block must contain numbers without repeats
- Fewer numbers: Only 4 or 6 numbers to track instead of 9
- Simpler logic: Easier to see patterns and eliminations
- Great for learning: Perfect introduction to Sudoku concepts
Best For: Beginners, kids, quick solving sessions, learning basic techniques
2. Classic Sudoku
With a familiar-looking 9×9 grid pattern, these puzzles follow standard Sudoku rules, and you can find them in a variety of difficulty levels to suit a wide range of solving skills.
Grid Style: 9×9
Unique Twist: Standard Sudoku rules with no additional constraints
Difficulty Level: Varies from easy to evil
Difficulty Breakdown:
- Easy: Best for learning rules and basic techniques like scanning
- Medium: Helps add solving skills using techniques like naked pairs and last possible candidate
- Hard: Requires wide range of Sudoku techniques
- Expert: Even fewer givens, requires techniques like XY-wing and unique rectangle
- Evil: Advanced skills needed for these difficult puzzles
How to Solve:
- Start with scanning: Look for obvious placements
- Use basic techniques: Naked singles, hidden singles, pairs
- Progress to advanced: X-wing, swordfish, skyscraper for harder puzzles
- Track candidates: Use pencil marks or candidate mode
Best For: All skill levels, entry point for beginners, foundation for learning variants
3. Super/Giant Sudoku
These 16×16 puzzles (or larger!) expand the classic 9×9 grid into an oversized challenge. Solvers must apply the same Sudoku solving strategies, but on a much larger scale.
Grid Style: 16×16 or larger
Unique Twist: Oversized grid requiring numbers 1-9 and letters A-G (for 16×16)
Difficulty Level: Advanced
How to Solve:
- Same strategies: Apply standard Sudoku techniques on larger scale
- More candidates: Track more numbers/letters across larger grid
- Systematic approach: Methodical scanning and candidate tracking essential
- Time commitment: Requires longer solving sessions
Best For: Advanced solvers, marathon solving sessions, experienced players seeking challenge
Shape and Grid Variants
These versions of Sudoku twist the familiar puzzle type by changing the shape of the units (rows, columns, and blocks) or by combining multiple grids. They look familiar, but you'll discover they play very differently from standard Sudoku, although you can often still use many of the basic Sudoku techniques for solving.
4. Jigsaw Sudoku
Instead of square blocks, jigsaw Sudoku (also called irregular Sudoku) uses odd-shaped regions. You still must place the same numbers 1 to 9 in each row and column, but instead of a uniform block layout, you have to also place the numbers, with no repeats, inside of each puzzle-looking piece.
Grid Style: 9×9 with odd-shaped regions
Unique Twist: Irregular regions replace standard 3×3 blocks
Difficulty Level: Intermediate
How to Solve:
- Adapt techniques: Use standard Sudoku techniques but adapt to irregular shapes
- Focus on regions: Pay attention to irregular region boundaries
- Row/column first: Start with row and column scanning
- Pattern recognition: Look for patterns within irregular regions
Best For: Intermediate solvers, players seeking visual variety, those who enjoy spatial challenges
5. Samurai Sudoku (Gattai Sudoku)
Also called Gattai, this Sudoku variant uses five overlapping 9×9 grids arranged in an X shape. Samurai Sudoku puzzles can take much longer to solve and are best tackled by advanced solvers.
Grid Style: Five overlapping 9×9 grids
Unique Twist: Multiple grids must be solved simultaneously with overlapping corners
Difficulty Level: Advanced
How to Solve:
- Overlapping constraints: Use overlapping corners as additional restriction points
- Compare units: Compare units and candidates across grids
- Advanced strategies: Apply advanced techniques to individual blocks
- Systematic approach: Work through grids methodically
- Time commitment: Requires extended solving sessions
Best For: Advanced solvers, marathon solving sessions, experienced players seeking ultimate challenge
6. Windoku
This version of Sudoku, which is also called hyper Sudoku, adds four extra shaded 3×3 regions within the grid, like windows. Numbers 1 to 9 must appear in these areas, too, increasing difficulty beyond normal Sudoku.
Grid Style: 9×9 grid with extra regions
Unique Twist: Four additional shaded 3×3 regions must also contain numbers 1-9
Difficulty Level: Intermediate
How to Solve:
- Extra constraints: Additional regions provide more restriction points
- Narrow possibilities: Shaded areas help narrow candidate possibilities
- Adapt techniques: Use standard techniques with extra region awareness
- Pattern recognition: Look for patterns within extra regions
Best For: Intermediate solvers, players seeking moderate challenge, those who enjoy additional constraints
Rule-Based Sudoku Variants
These Sudoku variations add extra rules on top of the classic 9×9 grid, creating fresh challenges for experienced solvers.
7. Sudoku X (Diagonal Sudoku)
Known as Sudoku X or X-Sudoku, this variant requires digits 1 to 9 to also appear once along both main diagonals of the 9×9 grid.
Grid Style: 9×9 grid with diagonals
Unique Twist: Both main diagonals must also contain numbers 1-9 exactly once
Difficulty Level: Intermediate
How to Solve:
- Diagonal scanning: Check diagonals for placements and eliminations
- Extra constraints: Diagonals provide additional restriction points
- Candidate elimination: Use diagonal constraints to eliminate candidates
- Adapt techniques: Apply standard techniques with diagonal awareness
Best For: Intermediate solvers, players seeking moderate challenge, those who enjoy geometric constraints
8. Skyscraper Sudoku
In Skyscraper Sudoku, the numbers in each cell of the 9×9 grid represent the height of skyscrapers. Clues outside the grid tell you how many skyscrapers are "visible" in that row or column.
Grid Style: 9×9 grid with outside clues
Unique Twist: Outside numbers show how many skyscrapers are visible from each side
Difficulty Level: Advanced
How to Solve:
- Visibility logic: Taller numbers block smaller ones behind them
- Outside clues: Use outside numbers to determine placements
- Spatial reasoning: Combine Sudoku logic with spatial visibility puzzles
- Advanced techniques: Requires combination of Sudoku and visibility strategies
Best For: Advanced solvers, players who enjoy spatial puzzles, those seeking complex challenges
9. Killer Sudoku
This puzzle type combines Sudoku with arithmetic. Numbers must obey the standard Sudoku rules for placement, but the digits within outlined cages must also add up to the sum contained in the cage.
Grid Style: 9×9 grid with cages
Unique Twist: Digits in cages must add up to given totals
Difficulty Level: Advanced
How to Solve:
- Arithmetic constraints: Use cage sums to determine possible number combinations
- Combination logic: Determine which numbers can fit in each cage
- Standard rules: Still follow row, column, and block rules
- Advanced techniques: Combine arithmetic with Sudoku logic
Best For: Advanced solvers, math enthusiasts, players who enjoy arithmetic challenges
Math-Based Sudoku Variations
Some Sudoku variations go beyond simple placement rules by adding arithmetic into the mix. These puzzles require solvers to use consecutive digits, calculate sums, compare values with inequality signs, or apply even-odd restrictions while still following the standard Sudoku rules.
10. Even-Odd Sudoku
Some cells are shaded to require even or odd numbers only. This simple rule dramatically shifts how solvers approach candidate elimination compared to standard Sudoku.
Grid Style: 9×9 grid with shaded cells
Unique Twist: Shaded cells restricted to even/odd numbers only
Difficulty Level: Beginner to Intermediate
How to Solve:
- Even/odd elimination: Narrow candidates by even/odd restrictions
- Shaded cell focus: Pay attention to which cells are shaded
- Candidate reduction: Eliminate half of possible numbers immediately
- Standard techniques: Apply standard Sudoku techniques with even/odd awareness
Best For: Beginners to intermediate solvers, players learning constraint-based solving
11. Consecutive Sudoku
In this Sudoku version, adjacent cells marked with a symbol must contain consecutive digits. In non-consecutive versions, no two adjacent cells may contain consecutive numbers.
Grid Style: 9×9 grid with marked dots
Unique Twist: Adjacent cells with symbols must contain consecutive digits
Difficulty Level: Intermediate
How to Solve:
- Consecutive logic: Use consecutive constraints to eliminate candidates
- Symbol recognition: Identify which cells have consecutive requirements
- Combination logic: Determine possible consecutive pairs
- Standard techniques: Apply standard Sudoku techniques with consecutive awareness
Best For: Intermediate solvers, players who enjoy number sequence logic
12. Greater-Than Sudoku
Sometimes called Inequality Sudoku, this puzzle places comparison signs (< or >) between cells. Solvers must respect both the Sudoku rules and the inequality clues.
Grid Style: 9×9 grid with inequality signs
Unique Twist: Cells must respect inequality clues between adjacent cells
Difficulty Level: Intermediate
How to Solve:
- Inequality logic: Use comparison signs to eliminate candidates
- Relationship tracking: Track which numbers are greater/less than others
- Candidate elimination: Use inequalities to narrow possibilities
- Standard techniques: Apply standard Sudoku techniques with inequality awareness
Best For: Intermediate solvers, players who enjoy comparison logic
13. Arrow Sudoku
In Arrow Sudoku, the numbers along each arrow must add up to the total in the circle at its base. This adds a layer of arithmetic similar to killer Sudoku.
Grid Style: 9×9 grid with arrows
Unique Twist: Digits in arrows must add up to circle totals
Difficulty Level: Advanced
How to Solve:
- Arithmetic constraints: Use arrow sums to determine possible combinations
- Sum logic: Calculate which numbers can fit along each arrow
- Standard rules: Still follow row, column, and block rules
- Advanced techniques: Combine arithmetic with Sudoku logic
Best For: Advanced solvers, math enthusiasts, players who enjoy arithmetic challenges
Visual Variants
These Sudoku puzzles replace numbers with letters, words, shapes, or colors. The rules stay the same, but the look and theme make them accessible to different skill levels.
14. Wordoku
Instead of digits, Wordoku uses letters A through I in a 9×9 grid. Sometimes the letters spell a hidden word, adding a fun extra challenge.
Grid Style: 9×9 grid with letters
Unique Twist: Numbers replaced with letters A-I
Difficulty Level: Beginner to Intermediate
How to Solve:
- Same logic: Apply standard Sudoku techniques with letters
- Letter tracking: Track letters instead of numbers
- Hidden words: Look for words formed by letters (if applicable)
- Visual appeal: More approachable for some players
Best For: Beginners to intermediate solvers, word puzzle enthusiasts, visual learners
15. Color Sudoku
Instead of numbers, solvers place colors, symbols, or pictures. This makes the puzzle more approachable for kids and those new to Sudoku variations, but the logic puzzle structure remains the same.
Grid Style: 9×9 grid with colors
Unique Twist: Numbers replaced with colors, symbols, or pictures
Difficulty Level: Beginner to Intermediate
How to Solve:
- Same logic: Apply standard Sudoku techniques with colors/symbols
- Visual tracking: Track colors/symbols instead of numbers
- Pattern recognition: Use visual patterns instead of numerical
- Accessibility: More approachable for visual learners
Best For: Beginners, kids, visual learners, those new to Sudoku
How to Choose the Right Sudoku for You
With so many different types of Sudoku, you can pick puzzles based on your skill level, mood, and preferences. Whether you're browsing online Sudoku puzzles or flipping through puzzle books, use these tips to pick the right puzzle type:
Start with Classic Sudoku
If you're new to the game, stick with the standard 9×9 grid. It's the best way to learn the Sudoku rules and build confidence.
Why Start Here:
- Foundation: Learn basic rules and techniques
- Confidence building: Build solving skills gradually
- Skill development: Master fundamentals before variants
- Difficulty progression: Easy to evil levels available
Pick the Right Skill Level
You can choose from a variety of levels in classic Sudoku, but different types of Sudoku offer even more puzzling adventures at different levels of difficulty.
Beginner Options:
- Mini Sudoku: 4×4 or 6×6 grids, perfect for learning
- Wordoku: Letters instead of numbers, more approachable
- Color Sudoku: Visual elements, great for kids
- Even-Odd Sudoku: Simple constraints, good for learning
Intermediate Options:
- Sudoku X (Diagonal): Moderate challenge with diagonal constraints
- Jigsaw Sudoku: Irregular regions, spatial challenge
- Windoku: Extra regions, moderate difficulty
- Consecutive/Greater-Than: Math-based with moderate challenge
Advanced Options:
- Samurai Sudoku: Five overlapping grids, ultimate challenge
- Killer Sudoku: Arithmetic combined with Sudoku logic
- Skyscraper Sudoku: Spatial visibility puzzles
- Arrow Sudoku: Arithmetic constraints
Consider Your Time Commitment
Short Sessions:
- Mini Sudoku: Quick solving, perfect for breaks
- Easy Classic: Fast solving for busy schedules
- Wordoku/Color: Quick visual puzzles
Marathon Sessions:
- Samurai Sudoku: Extended solving time required
- Super/Giant Sudoku: Large grids need time commitment
- Hard/Expert Classic: Complex puzzles for longer sessions
Pick by Puzzle Style
Math Enthusiasts:
- Killer Sudoku: Arithmetic and sums
- Arrow Sudoku: Sum calculations
- Greater-Than Sudoku: Comparison logic
Pattern Lovers:
- Windoku: Extra regions and patterns
- Jigsaw Sudoku: Irregular shapes
- Color Sudoku: Visual patterns
Spatial Thinkers:
- Skyscraper Sudoku: Visibility and spatial logic
- Jigsaw Sudoku: Irregular regions
- Samurai Sudoku: Multiple overlapping grids
Summary
Sudoku has evolved far beyond the classic 9×9 grid, with 15 different types offering unique challenges, rules, and solving experiences. From Mini Sudoku's beginner-friendly 4×4 grids to Samurai Sudoku's five overlapping 9×9 grids, each type provides different levels of difficulty and appeal.
The 15 types are grouped into five categories: Classic and Size-Based (Mini, Classic, Super/Giant), Shape and Grid Variants (Jigsaw, Samurai, Windoku), Rule-Based (Sudoku X, Skyscraper, Killer), Math-Based (Even-Odd, Consecutive, Greater-Than, Arrow), and Visual Variants (Wordoku, Color).
Each type has unique characteristics: grid style, unique twist, and difficulty level ranging from Beginner to Advanced. Classic Sudoku serves as the best entry point, with difficulty levels from easy to evil. Size-based versions follow standard rules on different scales, while shape variants twist familiar puzzles by changing unit shapes or combining multiple grids.
Rule-based variants add extra constraints (diagonals, outside clues, cages) creating fresh challenges for experienced solvers. Math-based variations add arithmetic (consecutive digits, sums, inequalities, even-odd restrictions) requiring number theory combined with logical reasoning. Visual variants replace numbers with letters or colors, making puzzles more approachable while maintaining logical structure.
Choosing the right Sudoku depends on skill level (beginners start with Classic or Mini), time commitment (Mini for short sessions, Samurai for marathons), and puzzle style preferences (math-based for calculation lovers, visual for pattern enthusiasts).
With so many different types of Sudoku, you can always find a new puzzle to match your mood, skill level, or time commitment. Whether you're just learning how to play Sudoku or learning advanced sudoku strategies, you can explore and play a wide variety of Sudoku puzzles online today and see which version of Sudoku challenges you the most.
Ready to explore different Sudoku types? Try our Sudoku game, explore daily challenges, or check out our puzzle guides to learn more solving strategies!
❓ FAQ
Q1: What are the 15 types of Sudoku?
The 15 types of Sudoku are: Mini (4×4/6×6), Classic (9×9), Super/Giant (16×16+), Jigsaw (irregular regions), Samurai (five overlapping grids), Windoku (extra regions), Sudoku X (diagonals), Skyscraper (outside clues), Killer (cages), Even-Odd (shaded cells), Consecutive (marked dots), Greater-Than (inequality signs), Arrow (arithmetic), Wordoku (letters), and Color (colors/symbols).
Q2: Which Sudoku type is best for beginners?
Best for beginners: Mini Sudoku (4×4/6×6), Classic Sudoku (easy level), Wordoku (letters), Color Sudoku (visual), and Even-Odd Sudoku (simple constraints). These types have simpler rules, smaller grids, or visual elements that make them more approachable for learning.
Q3: What's the hardest type of Sudoku?
Hardest types: Samurai Sudoku (five overlapping grids), Killer Sudoku (arithmetic with cages), Skyscraper Sudoku (spatial visibility), Arrow Sudoku (arithmetic constraints), and Super/Giant Sudoku (16×16+ grids). These require advanced techniques, extended time, and complex logic.
Q4: How do I solve different Sudoku variants?
Solving different variants: (1) Understand the unique rules and constraints, (2) Adapt standard Sudoku techniques to the variant's requirements, (3) Use variant-specific strategies (arithmetic for math-based, spatial for shape variants), (4) Start with easier variants and progress to harder ones, (5) Practice regularly to develop variant-specific skills.
Q5: What's the difference between Classic and other Sudoku types?
Classic Sudoku uses a standard 9×9 grid with no additional rules beyond row, column, and block constraints. Other types add: size variations (Mini, Super/Giant), shape changes (Jigsaw, Samurai), extra rules (diagonals, cages, outside clues), math constraints (arithmetic, inequalities), or visual elements (letters, colors).
Q6: Can I use the same solving techniques for all Sudoku types?
Yes and no: Basic techniques (scanning, singles, pairs) work across most types, but each variant requires adaptation. Math-based types need arithmetic skills, shape variants need spatial awareness, and rule-based types need understanding of additional constraints. Advanced techniques may need modification for specific variants.
Q7: How do I choose the right Sudoku type for me?
Choose based on: (1) Skill level (beginners: Mini/Classic/Wordoku, intermediate: Sudoku X/Jigsaw, advanced: Samurai/Killer), (2) Time commitment (short: Mini, long: Samurai), (3) Preferences (math: Killer/Arrow, visual: Color/Wordoku, spatial: Skyscraper/Jigsaw), (4) Goals (learning: Classic, challenge: Samurai/Killer).
Q8: Are all Sudoku types available online?
Most Sudoku types are available online through various puzzle websites and apps. Classic, Mini, Killer, Sudoku X, and Jigsaw are widely available. Some specialized types like Samurai or Skyscraper may be less common but can be found on dedicated Sudoku platforms. Check online Sudoku sites for the types that interest you.
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