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Strategies for Number Puzzles of all kinds
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A quick list of the latest updates and additions to this site:

Date Created: Friday 11-Apr-2008
Last Updated: Wednesday 20-Feb-2019
Sudoku Strategy. BUG stands for Bi-Value Universal Grave. It is a formation that relies on the uniqueness of the solution and an array of bi-value cells.

Strategy Families
Date Created: Saturday 12-Apr-2008
Last Updated: Wednesday 23-Jan-2019
This is the index to the all the fully documented strategies used to solve Sudoku, Jigsaw Sudoku, Sudoku X and Killer Sudoku.

Using Unique Rectangles as Links in Chains
Date Created: Wednesday 23-Jan-2019
Last Updated: Wednesday 23-Jan-2019

Jellyfish Strategy
Date Created: Friday 11-Apr-2008
Last Updated: Monday 31-Dec-2018
Sudoku Strategy. Jelly-Fish extends Sword-Fish into four rows and four columns. Candidate eliminations are possible where the cells that form the Jelly-Fish are the only possible places for a solution on candidate N."

Interesting Sudokus
Date Created: Tuesday 4-Sep-2018
Last Updated: Tuesday 27-Nov-2018

How Sudoku X Breaks Symmetries
Date Created: Wednesday 7-Aug-2013
Last Updated: Friday 21-Sep-2018

Sudoku Solver for Android
Date Created: Saturday 15-Dec-2012
Last Updated: Sunday 26-Nov-2017

Empty Rectangles
Date Created: Saturday 12-Apr-2008
Last Updated: Sunday 26-Nov-2017
Sudoku Strategy. Empty Rectangles is a complex strategy that uses a variety of formations and the fact that a Sudoku puzzle should have a unique solution.

Grouped X-Cycles
Date Created: Saturday 12-Apr-2008
Last Updated: Friday 24-Nov-2017
Sudoku Strategy. All chains used in Alternating Inference Chains strategies can take advantage of grouped cells for the purpose of finding links. This explains how.

Sudoku Solver - Version History
Date Created: Sunday 13-Apr-2008
Last Updated: Friday 8-Sep-2017