The Solving Bible

A cell with only one possible candidate.

A candidate that appears in only one cell within a unit.

Two cells in a unit with the same two candidates.

Three cells in a unit whose combined candidates contain exactly three values.

Two values that appear as candidates in only two cells of a unit.

Three values confined to exactly three cells in a unit.

A candidate in a box restricted to a single row or column.

A candidate in a row or column restricted to a single box.

Four cells in a unit whose combined candidates contain exactly four values.

Four values confined to exactly four cells in a unit.

A candidate confined to two columns in exactly two rows, forming a rectangle.

A candidate confined to three columns across exactly three rows.

A pivot cell with two wings that share eliminating candidates.

Alternating chains of conjugate pairs reveal contradictions.

A candidate confined to four columns across exactly four rows.

Exploiting the uniqueness constraint to eliminate candidates from a rectangle pattern.