Sudoku Variants
Classic Sudoku is only the beginning. This collection explores the huge family of Sudoku variants, from famous ones like Killer, Thermo, Arrow and Kropki to overlapping giants like Samurai, Windmill and Sumo, and unusual boards such as Jigsaw, Diagonal and Anti-Knight. Each guide covers the extra rule, what changes about solving, and a few tactics to get you started.
Variants keep the core promise of Sudoku, a single logical solution, while adding a fresh constraint to reason about. They are a great way to keep the puzzle feeling new once standard grids start to feel easy.
72 articles in this collection
Sudoku Variant Glossary: Cages, Thermos, Whispers, and More
This plain-language sudoku variant glossary explains cages, thermos, whispers, and other terms so you can enjoy modern puzzles with confidence.
Sudoku Line Constraints: Whispers, Renban, Thermo, and More
Sudoku line constraints add rules along drawn lines like thermo and renban. Learn what whisper, palindrome, and zipper lines mean and how to solve.
How to Pick Your First Sudoku Variant: A Friendly Guide
Choosing your first sudoku variant is easier with a friendly guide. Compare classic, color, killer, and mini grids to find the one that fits you.
Chess Sudoku: Anti Knight, Anti King, and How Scanning Changes
Chess sudoku adds anti knight and anti king rules to the grid. Learn how chess moves forbid matching digits and how your scanning has to change.
Innies and Outies Sudoku: The 45 Rule for Killer Grids
Innies and outies sudoku uses the 45 rule to solve killer grids. Learn what innies and outies are and how to name a cell exactly from the 45 total.
Killer Sudoku Cage Strategy: Read the Small Cages First
Killer sudoku cage strategy turns tiny cage sums into deductions. Learn cage combinations, the no repeat rule, and why to read small cages first.
Gattai Sudoku Explained: Overlapping Grids and Samurai Layouts
Gattai sudoku overlaps several grids that share boxes, as in samurai. Learn why the shared boxes help most and how to solve the seams first.
12x12 Sudoku: Rules, Symbols, and Solving Strategy
12x12 Sudoku expands the grid to 144 cells. Learn the 12-symbol rules, 3x4 box structure, candidate tactics, and a manageable solving workflow.
4x4 Sudoku: Rules and Beginner Strategy
4x4 Sudoku uses digits 1 to 4 in rows, columns, and 2x2 boxes. Learn the rules, simple solving steps, and how the mini grid builds logic skills.
Butterfly Sudoku: Rules and Solving Strategy
Butterfly Sudoku combines four overlapping 9x9 grids. Learn the shared-region rules, central solving tactics, and a clear workflow for the layout.
Sohei Sudoku: Rules and Solving Strategy
Sohei Sudoku uses four overlapping 9x9 grids. Learn how the shared corner boxes work, where to start, and how to pass deductions between grids.
Flower Sudoku: Rules and Solving Strategy
Flower Sudoku links several overlapping 9x9 grids. Learn the rules, how shared boxes transfer information, and a practical solving workflow.
Sukaku Sudoku: Rules and Solving Strategy
Sukaku Sudoku replaces given digits with candidate lists. Learn the rules, how to read pencilmarks, and how to solve the full grid logically.
Miracle Sudoku: Rules and Solving Strategy
Learn Miracle Sudoku rules, how anti-knight, anti-king, and non-consecutive constraints combine, and how to turn local exclusions into placements.
Consecutive Sudoku: Rules and Solving Strategy
Learn Consecutive Sudoku rules, how marked neighbors differ by one, and how positive and negative adjacency clues can quickly narrow candidate pairs.
Magic Square Sudoku: Rules and Solving Strategy
Learn Magic Square Sudoku rules, how a marked 3x3 square uses equal sums, and how the special structure can force values before ordinary Sudoku does.
Argyle Sudoku: Rules and Solving Strategy
Learn Argyle Sudoku rules, how marked diagonals act as no-repeat units, and how to combine diagonal restrictions with classic row, column, and box logic.
Center Dot Sudoku: Rules and Solving Strategy
Learn Center Dot Sudoku rules, how the nine box centers form an extra region, and how that simple pattern creates powerful cross-grid deductions.
Girandola Sudoku: Rules and Solving Strategy
Learn Girandola Sudoku rules, how the nine windmill cells form an extra region, and how to turn that extra constraint into useful placements.
Clueless Sudoku: Nine Grids, One Hidden Tenth, Explained
Clueless sudoku links nine grids through a hidden tenth grid. Learn the overlap rules, how center cells connect, and a plan to solve the whole set.
Numbered Rooms Sudoku: Rules and Solving Strategy
Learn how Numbered Rooms clues use the first digit as an index and turn outside clues into precise position constraints.
Outside Sudoku: Rules and Solving Strategy
Learn how outside clues restrict the first three cells of rows and columns and create useful placements in Outside Sudoku.
Roman Numeral Sudoku and Why Symbols Never Change the Logic
Roman numeral sudoku swaps 1 to 9 for I to IX. Learn how symbol Sudoku works and why the solving logic stays exactly the same as always.
16x16 Sudoku and Hexadoku: Rules and Solving Strategy
Learn how 16x16 Sudoku works, which symbols it uses, and how to manage larger rows, 4x4 boxes, candidates, and scanning.
Asterisk Sudoku: Rules and Solving Strategy
Learn how the nine-cell asterisk region adds a new all-different unit and creates extra singles, pairs, and candidate interactions.
6x6 Sudoku: Rules, Box Sizes, and Beginner Strategy
Learn how 6x6 Sudoku works, how its smaller boxes differ from 9x9 grids, and which solving habits make it fast and clear.
Wordoku: How Letter Sudoku Works and How to Solve It
Learn how Wordoku replaces digits with letters, why the logic stays the same, and how to solve letter Sudoku without extra guesswork.
X-Sums Sudoku: Rules and Solving Strategy
Learn how outside X-Sums clues use the first digit to set a run length, then use totals and bounds to narrow the grid.
Greater Than Sudoku: Rules and Solving Strategy
Learn how inequality signs create upper and lower bounds, candidate chains, and precise placements in Greater Than Sudoku.
Non-Consecutive Sudoku: Rules and Solving Strategy
Learn how the non-consecutive rule changes candidate scanning and creates new eliminations between neighboring Sudoku cells.
Double Arrow Sudoku: Rules and Solving Strategy
Learn how Double Arrow lines balance endpoint sums with path sums and turn candidate totals into precise Sudoku deductions.
Rossini Sudoku: Rules and Solving Strategy
Learn how Rossini arrows control the first three edge digits and how missing arrows can create useful negative constraints.
Anti-King Sudoku: Rules and Solving Strategy
Learn how the anti-king rule blocks equal digits in neighboring cells and creates new scanning patterns across the grid.
Nabner Lines Sudoku: Rules and Solving Strategy
Learn how Nabner Lines forbid repeats and consecutive digits, then use line length and candidate spacing to solve them.
Lockout Lines Sudoku: Rules and Solving Strategy
Learn how Lockout Lines use separated endpoints and outside-range digits to create powerful candidate restrictions.
Frame Sudoku: How Outside Sum Clues Work and How to Solve
Frame sudoku prints sum clues outside the grid border. Learn how the outer three cell sums work, which totals are gold, and how to start solving.
Zipper Lines Sudoku: Rules and Solving Strategy
Learn how mirrored pairs on a Zipper Line sum to its center digit and use pair combinations to narrow the grid.
Fog of War Sudoku: Rules and Solving Strategy
Learn how to solve Fog of War Sudoku by revealing hidden cells through forced placements while avoiding guesses and stale assumptions.
Clone Sudoku: Rules and Solving Strategy
Learn how matching clone regions copy digits by position and use candidate intersections to transfer information across the grid.
Fortress Sudoku: Rules and Solving Strategy
Learn how shaded fortress cells compare with neighboring white cells and turn inequality chains into useful Sudoku deductions.
Dutch Whispers Sudoku: Rules and Solving Strategy
Learn the Dutch Whispers rule and use four-or-more differences, candidate ranges, and line interactions to solve the variant.
Disjoint Groups Sudoku: Rules and Solving Strategy
Learn how matching positions across all nine boxes form extra groups and create new singles, pairs, and locked candidates.
Region Sum Lines Sudoku: Rules and Solving Strategy
Learn how equal sums across box segments create equations, candidate totals, and useful deductions in Region Sum Lines Sudoku.
Modular Lines Sudoku: Rules and Solving Strategy
Learn how modular lines cycle through three remainder groups and use that pattern to narrow candidates across the grid.
Entropic Lines Sudoku: Rules and Solving Strategy
Learn how every three cells on an entropic line must include one low, one middle, and one high digit.
Battenburg Sudoku: Rules and Solving Strategy
Learn how Battenburg markers control odd-even checkerboards and turn parity patterns into precise Sudoku deductions.
Between Lines Sudoku: Rules and Solving Strategy
Learn how line digits must fall between two endpoint values and use ranges, extremes, and overlaps to narrow candidates.
Quadruple Sudoku: Rules and Solving Strategy
Learn how four-cell intersection clues work in Quadruple Sudoku and use them to place digits across neighboring boxes.
Even-Odd Sudoku: Rules and Solving Strategy
Learn how parity markers restrict cells to even or odd digits and combine those limits with classic Sudoku techniques.
XV Sudoku: Rules and Solving Strategy
Learn how X and V clues mark adjacent sums of 10 and 5, then combine those pairs with classic Sudoku candidates.
German Whispers Sudoku: Rules and Solving Strategy
Learn the German Whispers rule and use five-or-more differences, candidate ranges, and line overlaps to solve this Sudoku variant.
Extra Region Sudoku Rules and Strategy for Shaded Regions
Extra region sudoku adds a shaded area that must also hold 1 to 9 once. Learn the rules, why the extra region helps, and a solving strategy.
A Short History of Sudoku Variants
The history of sudoku variants traces one small grid into diagonal, killer, thermo and shape puzzles. See how a single idea kept branching outward.
Toroidal Sudoku: Wrap Around Rules and Solving Strategy
Toroidal sudoku wraps the grid so edges connect like a doughnut. Learn the wrap around rules, how regions cross the seam, and tactics to solve it.
Windoku and Hyper Sudoku: Rules and Solving Strategy
Learn how four extra 3x3 regions change classic Sudoku and create additional singles, locks, and candidate interactions.
Palindrome Sudoku: Rules and Solving Strategy
Learn how mirrored cells on palindrome lines must match and use symmetry to transfer placements and candidates across the grid.
Renban Sudoku: Rules and Solving Strategy
Learn how Renban lines contain consecutive digits in any order and use range limits to create strong Sudoku deductions.
Little Killer Sudoku: Rules and Solving Strategy
Learn how diagonal sum clues work in Little Killer Sudoku and combine them with rows, columns, boxes, and candidate totals.
Sandwich Sudoku: Rules and Solving Strategy
Learn how sandwich clues total the digits between 1 and 9, then combine those sums with classic Sudoku logic.
Jigsaw Sudoku: Rules and Solving Strategy
Learn how irregular regions replace 3 by 3 boxes in Jigsaw Sudoku and how to scan their unusual boundaries efficiently.
Kropki Sudoku: Dot Rules and Solving Strategy
Learn white and black Kropki dot rules, candidate pairs, and the important difference between positive and negative constraints.
Arrow Sudoku: Rules and Solving Strategy
Learn how Arrow Sudoku sums work and use length, parity, and classic Sudoku restrictions to narrow circles and arrow paths.
Thermo Sudoku: Rules and Beginner Strategy
Learn Thermo Sudoku rules, minimum and maximum digit bounds, and practical ways to combine thermometers with classic Sudoku logic.
Pinwheel Sudoku Rules and Strategy for the Rotational Grid
Pinwheel sudoku arranges overlapping 9x9 grids in a rotating pattern. Learn the rules, how to read the seams, and a clean solving order.
Anti-Knight Sudoku: Rules and Beginner Strategy
Learn the extra knight-move rule in Anti-Knight Sudoku and use it with classic row, column, and box logic.
Sumo Sudoku Rules and Strategy for the Giant Overlapping Grid
Sumo sudoku stacks many overlapping 9x9 grids into one huge gattai puzzle. Learn the rules and a calm strategy for taming its enormous size.
Windmill Sudoku Rules and Strategy for the Five-Grid Pinwheel
Windmill sudoku joins five overlapping 9x9 grids into one spinning pinwheel. Learn the rules, the shared corner boxes, and a smart solving order.
Popular Sudoku Variants, Explained Simply
A friendly tour of popular Sudoku variants, explained simply: X-Sudoku, Hyper, Killer, Samurai and Mini, and how each twist changes the classic grid.
Killer Sudoku: The Rules and How to Solve It
Killer sudoku adds cages with target sums to the classic grid. Learn the rules, the handy rule of 45, and the first strategies to crack one.
Diagonal Sudoku (Sudoku X), Explained
Diagonal sudoku, or Sudoku X, adds two corner-to-corner constraints to the classic grid. Learn how the extra diagonals work and how to solve them.
Samurai Sudoku, Explained
Samurai sudoku links five overlapping grids into one giant puzzle. Learn how the shared boxes work, plus a clear order of attack for solving it.
Jigsaw Puzzle Tips to Finish Faster
Practical jigsaw puzzle tips, from sorting and building the border to matching by shape, that turn a daunting box into a finished picture faster.