Shapedoku Articles · Page 6

Play smarter, think sharper

Guides for new players, strategies to solve faster, and the real benefits of a daily puzzle habit. Everything you need to get more out of Shapedoku and Sudoku.

Sudoku variants6 min read

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.

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Sudoku variants6 min read

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.

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Sudoku variants6 min read

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.

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Sudoku variants6 min read

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.

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Sudoku variants6 min read

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.

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Sudoku variants6 min read

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.

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Sudoku variants6 min read

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.

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Sudoku variants6 min read

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.

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Sudoku variants6 min read

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.

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Sudoku variants6 min read

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.

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Sudoku variants6 min read

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.

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Sudoku variants6 min read

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.

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Sudoku variants6 min read

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.

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Sudoku variants6 min read

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.

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Expert Sudoku7 min read

Alternating Inference Chains in Sudoku Explained

Learn how Alternating Inference Chains connect strong and weak candidate links to produce advanced Sudoku eliminations.

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Puzzle comparison6 min read

Sudoku vs Nonograms: Which Logic Puzzle Fits You

Compare Sudoku and nonograms by their clues, solving methods, difficulty, visual payoff, and the kind of attention each puzzle rewards.

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Sudoku variants6 min read

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.

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Advanced Sudoku7 min read

Franken Fish in Sudoku: An Advanced Fish Guide

Learn how Franken Fish mix boxes with rows or columns to extend X-Wing, Swordfish, and Jellyfish logic.

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Expert Sudoku7 min read

Aligned Pair Exclusion in Sudoku Explained

Learn how testing candidate combinations in two cells can rule out values that would break nearby Almost Locked Sets.

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Expert Sudoku7 min read

Pattern Overlay Method in Sudoku: A Practical Guide

Learn how Sudoku templates reveal candidates that can never appear, or must appear, across every valid pattern for one symbol.

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Puzzle comparison6 min read

Sudoku vs Connect Puzzles: Which Logic Style Fits You

Compare Sudoku and connect puzzles by their rules, planning style, mistakes, and the kind of attention each game rewards.

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Sudoku practice6 min read

How to Solve Sudoku Without Notes

Use systematic scanning, missing-symbol lists, and short memory loops to solve easier Sudoku puzzles without pencil marks.

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Sudoku structure6 min read

Minimal vs Minimum Sudoku Puzzles: What Is the Difference

Learn the difference between a minimal Sudoku and a minimum-clue puzzle, and why neither label tells you how hard the solve will be.

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Sudoku scanning6 min read

Chute Scanning in Sudoku: How Bands and Stacks Reveal Placements

Use bands, stacks, and box interactions to find hidden placements that ordinary cell-by-cell scanning can miss.

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