Learn with Solvo

Interactive sudoku lessons with Solvo, our logical-step helper: from the first single to advanced chains, and every variant rule explained on a real board.

Solving techniques

Rules and scanning · Candidate notes · Hidden Single · Naked Single · Notation and terms · Pointing · Claiming · Naked Pair · Hidden Pair · Naked Triple · Hidden Triple · Naked and Hidden Quads · X-Wing · Remote Pair · Skyscraper · Two-String Kite · Empty Rectangle · Turbot Fish · Y-Wing · XYZ-Wing · W-Wing · Swordfish · Simple Colouring · Unique Rectangle · BUG+1 · Finned X-Wing and Swordfish · Jellyfish · Finned and Sashimi Jellyfish · X-Chain · XY-Chain · WXYZ-Wing · Alternating Inference Chains · ALS-XZ · Forcing Chain · Set theory and Phistomefel’s ring · Law of leftovers · Killer innies and outies · Killer cages · Thermometer bounds · Arrow sums · German whispers · Kropki dots · Why 17 clues?

Variant rules

Thermo sudoku · Slow Thermo sudoku · Arrow sudoku · Double Arrow sudoku · Whisper sudoku · Dutch Whisper sudoku · Parity Line sudoku · Renban sudoku · Nabner sudoku · Palindrome sudoku · Between sudoku · Zipper sudoku · Lockout sudoku · Entropic sudoku · Modular sudoku · Anti Factor sudoku · Region Sum sudoku · Equal Sum sudoku · Ten Line sudoku · Killer sudoku · Quadruple sudoku · Clone sudoku · Extra Region sudoku · Windoku sudoku · Disjoint Groups sudoku · Kropki sudoku · Xv sudoku · Consecutive sudoku · Negative sudoku · Greater Than sudoku · Odd Even sudoku · Min Max sudoku · Sandwich sudoku · Little Killer sudoku · X Sums sudoku · Skyscrapers sudoku · Anti Knight sudoku · Anti King sudoku · Non Consecutive sudoku · Diagonal sudoku

Logic puzzles

Yin Yang · Yin-Yang Fillomino · Hitori · Heyawake · Nurikabe · Star Battle · Cave · Samurai

Written solving guides · Make your own puzzle · Puzzle library