Rooted: Created page with "'''Cross-Hatching''' is a simple method by which players can find Hidden Singles in a Sudoku puzzle. It is one of the few methods that does not depend on the presence..."

2020-05-31T05:25:03Z

Created page with "'''Cross-Hatching''' is a simple method by which players can find Hidden Singles in a Sudoku puzzle. It is one of the few methods that does not depend on the presence..."

New page

'''Cross-Hatching''' is a simple method by which players can find [[Hidden Single]]s in a [[Sudoku]] puzzle.
It is one of the few methods that does not depend on the presence of [[pencilmark]]s.

The primary target of Cross-Hatching are the [[box]]es, but the method will also work with [[row]]s and [[column]]s.

== How it Works ==
The player selects a digit that has already been placed several times in the [[grid]], but not all (9) instances have been placed. The player then focuses on a single box or [[line]], drawing imaginary lines from the cells outside this box or line which contain this digit. The lines mark the invalid positions for this digit. Cells already containing another digit are also excluded.

An example:
.-------.-------.-------.
| 1-----|-------|-+-----|
| . . . | . . . | | 2 3 |
| . . . | . . . | | . 4 |
:-------+-------+-------:
| . . . | . . . | | . . |
| . . . | . . . | | . . |
| . . . | . . . | 1 . . |
'-------'-------'-------'
We are inspecting digit '''1''', box 3. The placement in '''r1c1''' eliminates the [[candidate]]s from row 1. The placement in '''r6c7''' eliminates the candidates from column 7. Of the remaining 4 cells, 3 already contain another digit. We can now place digit '''1''' in '''r3c8''', because all other candidates in box 3 are [[eliminate]]d.
[[Category:Solving Techniques]]

Cross-Hatching - Revision history

Rooted: Created page with "'''Cross-Hatching''' is a simple method by which players can find Hidden Singles in a Sudoku puzzle. It is one of the few methods that does not depend on the presence..."