Learning path

8 chapters, easiest technique first.

The path decides what you learn next, so you never open a forcing chain before you can spot a single. Every stop pairs a written explanation with worked examples on a real board. Browse the technique library instead.

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FoundationsSummit

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Foundations

How the grid constrains itself, and how to keep notes you can trust.

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Reading the grid

3 min readReading only — no worked examples for this one yet

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Pencil marksArticle coming soon4 min

Singles

Placing digits. The only family that fills cells rather than clearing notes.

Unlocks after Foundations

3 techniquesLast Possible NumberNaked SingleHidden SingleRead ahead in the library

Locked candidates

Where a box and a line overlap, one constraint leaks into the other.

Unlocks after Singles

3 techniquesPointing PairClaiming GroupPointing TripleRead ahead in the library

Subsets

Groups of cells that own a group of digits. Nothing gets placed — notes get cleared.

Unlocks after Locked candidates

6 techniquesNaked PairHidden PairNaked TripleHidden Triple+2Read ahead in the library

Fish

One digit, boxed into a rectangle of rows and columns.

Unlocks after Subsets

3 techniquesX-WingSwordfishJellyfishRead ahead in the library

Wings

A pivot cell that sees two wings, forcing a shared conclusion.

Unlocks after Fish

3 techniquesY-WingXYZ-WingW-WingRead ahead in the library

Chains & coloring

Alternating links that carry a conclusion across the whole grid.

Unlocks after Wings

20 techniquesSimple ColoringX-ChainX-Chain Cell GroupsShort AIC+16Read ahead in the library

ALS & exotics

The summit — almost-locked sets, uniqueness, and the techniques built on them.

The summit

7 techniquesBUG+1Restricted Common CandidateAligned Pair ExclusionAligned Triple Exclusion+3Read ahead in the library