Advanced sets, fish, wings and strong links

Larger subsets (quads), bigger fish (Jellyfish), four-cell almost-locked-set wings and rings, and grouped three-link strong-link chains.

Naked Quad

Four cells restricted to four combined candidates.

Hidden Quad

Four digits confined to four cells in one house.

Candidate 2 forms a Jellyfish across four Sudoku rows and columns

WXYZ-Wing

A single-linked four-cell almost-locked-set wing.

WXYZ-Ring

The double-linked WXYZ form in which both restricted commons create a loop.

3 Skyscrapers

Three ungrouped parallel strong links connected in sequence.

3-String Kite

Three ungrouped strong links alternating between rows and columns.

A chain of three strong links connects highlighted Sudoku candidates

3 Strong Links

A general chain of three ungrouped conjugate pairs.

Grouped 3 Skyscrapers

A three-Skyscraper pattern containing at least one grouped strong link.

Grouped 3-String Kite

A three-string kite containing at least one grouped strong link.

Three grouped strong links connect highlighted Sudoku candidates

Grouped 3 Strong Links

A three-link chain containing one or more grouped conjugate links.

Three strong links form an X-Loop through highlighted Sudoku candidates

(3 Strong Links) X-Loop

Three strong links close into an ungrouped X-Loop.

Three grouped strong links form an X-Loop through highlighted candidates

(3 Strong Links) Grouped X-Loop

Three strong links, including a grouped link, close into an X-Loop.

Advanced Sudoku pattern families

This group scales familiar logic into larger structures. Naked and Hidden Quads restrict four digits to four cells in one house. A Jellyfish is a size-four fish, distributing one candidate across four base rows and four cover columns, or vice versa. These patterns can be difficult to scan, but the proof remains the same set-based accounting used for pairs, triplets, X-Wings and Swordfish.

WXYZ-Wings and WXYZ-Rings use four-cell almost-locked-set logic: restricted common candidates connect the cells and justify eliminations from their shared peers. The remaining guides extend strong-link reasoning through three-link Skyscrapers, String Kites and X-Loops, including grouped forms where several candidates act as one logical node. Accurate house membership, candidate visibility and link direction matter more than the pattern’s visual shape; each article breaks those conditions into a verifiable deduction.

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