What are some patterns found in sudoku puzzles?

Sudoku puzzles are designed with a specific set of patterns and rules to ensure there is one unique solution. Here are some of the most common patterns:

Basic Rules and Patterns:

* Single Candidate: A cell where only one possible number can be placed.

* Hidden Single: A number that is the only possible candidate in a row, column, or 3x3 block.

* Naked Single: A cell where a number is the only possible candidate in that specific row, column, and 3x3 block.

* Pair/Triplet/Quadruplet: Two or more cells in a row, column, or block that share the same two (pair), three (triplet), or four (quadruplet) potential candidates. This eliminates other numbers from those cells.

* Hidden Pair/Triplet/Quadruplet: Two or more cells in a row, column, or block where a pair/triplet/quadruplet of numbers are the only candidates for those cells, even though they might not be all the candidates in those cells.

* X-Wing/Swordfish/Jellyfish: This pattern involves two or more rows/columns that share the same two candidates, allowing you to eliminate those candidates from other cells in the same rows/columns.

Advanced Patterns:

* Unique Rectangle: Two pairs of cells in different rows and columns, where the same two candidates exist in both pairs. This eliminates the candidates from other cells in the same rows and columns.

* Y-Wing: Three cells with three candidates, where two of the candidates are shared between two of the cells, and the third cell has a unique candidate. This eliminates the shared candidate from other cells in the same rows, columns, and block.

* W-Wing: Two pairs of cells, where each pair shares the same two candidates. Additionally, each pair has a third unique candidate. This pattern allows you to eliminate one of the shared candidates from a specific cell.

* Forcing Chains: A chain of cells linked by candidates, where a specific choice in one cell will force a specific choice in another cell, and so on. This can help you eliminate candidates in other cells.

Strategic Approaches:

* Scanning: Look for cells with only a few candidates and prioritize those.

* Pencil Marking: Use pencil marks to note potential candidates in each cell.

* Working Backwards: Sometimes, starting with a cell that has fewer potential candidates and working your way back can help you uncover other clues.

These are just some of the common patterns you may encounter in Sudoku puzzles. As you become more experienced, you'll develop your own strategies and recognize more complex patterns.