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Sudoku technique · Specialty reference · reference
Death Blossom
Each candidate in a stem cell excludes a digit from a linked ALS petal, locking that petal. A common petal digit may become unavoidable.
How to spot it
Every stem possibility must be covered by a valid petal.
The common mistake
Ignoring one stem candidate leaves an untested case and invalidates the elimination.
Learn this first
ALS-XZ.
Further reading: hodoku.sourceforge.net