Techniques
The best techniques, tips and tricks to solve sudokus
Technique Index
First Tips
In this first lesson we will present some useful tips when solving sudokus.
OpenBasic Method
The easiest way to discover a number is when there is only one number left to put in a row, column or box. In this case the missing number goes in the only empty cell left.
OpenRow and Column Cross
Another way to discover numbers is to make a cross by row and column. This consists of focusing attention on a cell and checking what numbers can go in that position, eliminating those that are in the same row or column.
OpenLocked Candidates
Locked Candidates is an advanced strategy built on the interplay between a box and a line: when all of a digit's candidates in a row or column fall inside a single box (or all of a box's candidates fall on one line), the digit can be removed from the rest of that box or line.
OpenNaked Pairs
Naked Pairs: when two cells in the same row, column or box hold exactly the same two candidates, those two digits are locked into that pair and can be removed from the rest of the unit.
OpenHidden Pairs
When two digits can only go in the same two cells of a unit, those cells must hold that pair — clearing every other candidate from them.
OpenNaked Triples
Three cells in a unit that together use only three candidates lock those digits between them, removing them from the rest of the unit.
OpenHidden Triples
When three digits can only go in the same three cells of a unit, those cells reduce to that trio — every other candidate is cleared from them.
OpenX-Wing
When a digit is confined to the same two columns in two rows, it forms a rectangle and can be removed from those columns elsewhere.
OpenSwordfish
The Swordfish technique is used in sudokus when a specific number appears as possible in exactly three rows and three columns.
OpenXY-Wing
A two-candidate pivot links two pincer cells that share a third digit, which can then be eliminated from any cell both pincers see.
OpenXYZ-Wing
XYZ-Wing focuses on finding three cells that form a connection, where two have two possible numbers and the third (pivot) shares a number with each of the other two.
OpenSkyscraper
A single-digit pattern: a digit is a conjugate pair in two rows that share a base column, eliminating it from any cell that sees both roof cells.
OpenJellyfish
The four-line extension of the swordfish: a single candidate confined to the same four columns across four rows.
OpenW-Wing
Two cells with the same two candidates, linked by a strong link on one of them, eliminate the other candidate from any cell that sees both.
OpenDo you know more techniques?
If you know any additional techniques for solving sudokus that we haven't mentioned, we'd love to hear from you. Your knowledge could help other sudoku enthusiasts improve their skills.
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