Sitemap
Explore all pages and features available on Sudojo
Languages
Sudojo is available in multiple languages. Select your preferred language:
Main Pages
Levels
Techniques
- Full HouseFull House is the most fundamental Sudoku solving technique. It applies when a h
- Hidden SingleA Hidden Single occurs when a digit can only go in one cell within a house (row,
- Naked SingleA Naked Single is the simplest pencilmark technique. When a cell has only one ca
- Hidden PairA Hidden Pair occurs when two candidates appear in exactly two cells within a ho
- Naked PairA Naked Pair consists of two cells in the same house that contain exactly the sa
- Locked CandidatesLocked Candidates occurs when candidates in a block are restricted to a single r
- Hidden TripleA Hidden Triple extends the Hidden Pair concept to three cells and three candida
- Naked TripleA Naked Triple consists of three cells in a house that together contain exactly
- Hidden QuadA Hidden Quad is the four-cell extension of Hidden Pairs and Triples. When four
- Naked QuadA Naked Quad consists of four cells in a house that together contain exactly fou
- X-WingX-Wing is a fish pattern using two rows and two columns. When a candidate appear
- SwordfishSwordfish extends X-Wing to three rows and three columns. When a candidate appea
- JellyfishJellyfish is the four-row, four-column extension of fish patterns. When a candid
- XY-WingXY-Wing uses three bi-value cells arranged so each pair shares a candidate. The
- Finned X-WingA Finned X-Wing is an X-Wing with extra candidates (the "fin") in one of the bas
- SquirmbagSquirmbag (or Sixfish) is a five-row, five-column fish pattern. It's extremely r
- Finned SwordfishA Finned Swordfish is a Swordfish pattern with extra candidates forming a fin. E
- Finned JellyfishA Finned Jellyfish is a Jellyfish pattern with a fin. Eliminations are restricte
- XYZ-WingXYZ-Wing extends XY-Wing by having the pivot cell contain three candidates. The
- WXYZ-WingWXYZ-Wing uses four cells with candidates forming a restricted pattern. When pro
- Almost Locked SetsAn Almost Locked Set (ALS) is a group of N cells containing N+1 candidates. If o
- Finned SquirmbagA Finned Squirmbag is a Squirmbag (5-fish) pattern with extra candidates forming
- ALS ChainALS-Chain links multiple ALS groups through restricted common candidates. When A
- SkyscraperSkyscraper is a single-candidate pattern using two conjugate pairs. When two row
- Two-String KiteTwo-String Kite uses two conjugate pairs for a single digit, with one pair in a
- Empty RectangleEmpty Rectangle uses the absence of a candidate in a rectangular area within a b
- Simple ColoringSimple Coloring (Singles Chains) uses two colors to track conjugate pairs of a s
- W-WingW-Wing consists of two identical bi-value cells connected by a strong link on on
- Remote PairsRemote Pairs uses a chain of bi-value cells all containing the same two candidat
- Unique Rectangle Type 1Unique Rectangle Type 1 prevents a deadly pattern where four cells with identica
- Unique Rectangle Type 2Unique Rectangle Type 2 is similar to Type 1, but two cells (on the same side) s
- BUG+1BUG (Bivalue Universal Grave) is a state where all cells have exactly two candid
- Sue de CoqSue de Coq uses cells at the intersection of a box and line, combined with compa
- ALS-XZALS-XZ is the simplest ALS chain technique. Two Almost Locked Sets share a restr
- X-CyclesX-Cycles are chains of strong and weak links for a single digit that form loops.
- Forcing ChainsForcing Chains explore what happens when a cell is assumed to be each of its can
- Medusa ColoringMedusa Coloring (3D Medusa) extends Simple Coloring to multiple digits by using
- CraneCrane uses two conjugate pairs of the same digit: one in a box and one in a line
- Unique Rectangle Type 3Unique Rectangle Type 3 has two floor cells with only the deadly pair and two ro
- Unique Rectangle Type 4Unique Rectangle Type 4 occurs when one of the deadly pair digits forms a conjug
- Unique Rectangle Type 5Unique Rectangle Type 5 occurs when two diagonal cells of the rectangle share an
- X-ChainX-Chain is a single-digit chain technique that connects cells through alternatin
- XY-ChainXY-Chain links bivalue cells (cells with exactly 2 candidates) through shared ca
- VWXYZ-WingVWXYZ-Wing uses five cells whose combined candidates total exactly five digits.
- UVWXYZ-WingUVWXYZ-Wing is a six-cell wing pattern with six combined candidates. It extends
- TUVWXYZ-WingTUVWXYZ-Wing is a seven-cell wing pattern, extending the wing family further. Se
- STUVWXYZ-WingSTUVWXYZ-Wing is the largest wing pattern, using eight cells with eight combined
- AICAlternating Inference Chain (AIC) is a powerful chain technique that links candi
- Forcing NetForcing Net extends Forcing Chains by following all implications from each candi
- Avoidable RectangleAvoidable Rectangle is similar to Unique Rectangle but involves solved cells. Wh
- Sashimi X-WingSashimi X-Wing is a variant of Finned X-Wing where one of the base cells is miss
- Sashimi SwordfishSashimi Swordfish is a Swordfish variant where one or more base cells are missin
- Sashimi JellyfishSashimi Jellyfish is the four-row variant of sashimi fish. A Jellyfish pattern w
- Hidden Unique RectangleHidden Unique Rectangle identifies a deadly pattern where the UR digit is 'hidde
- FireworkFirework uses a pivot cell at the intersection of a row and column, where a digi
- Death BlossomDeath Blossom uses a stem cell connected to multiple Almost Locked Sets (petals)
- Franken X-WingFranken X-Wing extends the basic X-Wing by allowing boxes as base or cover sets
- Franken SwordfishFranken Swordfish is a 3-house Franken fish that mixes boxes with rows and colum
- Franken JellyfishFranken Jellyfish is a 4-house Franken fish combining boxes with rows and column
- Grouped X-CyclesGrouped X-Cycles extend X-Cycles by allowing grouped nodes - where multiple cell