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A quick list of the latest updates and additions to this site:

Unique Rectangles
Date Created: Friday 11-Apr-2008
Last Updated: Sunday 6-Dec-2015
Sudoku Strategy. Unique Rectangles takes advantage of the fact that published Sudokus have only one solution. There are many formations and strategies based on this notion and are explained here.

What's New
Date Created: Monday 17-Aug-2009
Last Updated: Sunday 29-Nov-2015

Sudoku Solver - Version History
Date Created: Sunday 13-Apr-2008
Last Updated: Thursday 12-Nov-2015

3D Medusa
Date Created: Saturday 6-Mar-2010
Last Updated: Tuesday 6-Oct-2015
Sudoku Strategy. 3D Medusa takes chain building into all the dimensions of the Sudoku board. That is, by making links among rows, columns and boxes - and in bi-value cells. Many types of eliminations are possible with this network approach.

Sword-Fish Strategy
Date Created: Friday 11-Apr-2008
Last Updated: Saturday 1-Aug-2015
Sudoku Strategy. Sword-Fish extends X-Wings into three rows and three columns. Candidate eliminations are possible where the cells that form the Sword-Fish are the only possible places for a solution on candidate N.

Date Created: Friday 11-Apr-2008
Last Updated: Thursday 2-Jul-2015
Sudoku Strategy (Depreciated). Bugs stands for Bi-Value Universal Grave. It is a formation that replies on the uniqueness of the solution and an array of bi-value cells.

Main Page
Date Created: Thursday 10-Apr-2008
Last Updated: Saturday 16-May-2015
Strategies for Sudoku, Sudoku X, Killer Sudoku and Jigsaw Sudoku - and the home of logical puzzle maker Andrew Stuart

Single's Chains
Date Created: Saturday 29-Jan-2011
Last Updated: Saturday 25-Apr-2015
Sudoku Strategy. Single's Chains, also known as Simple Colouring is a chaining strategy and part of a large family of such strategies. Cells and units with only two remaining candidates N are used to make links and find contradictions.

Finned X-Wing
Date Created: Saturday 12-Apr-2008
Last Updated: Sunday 29-Mar-2015
Sudoku Strategy. Finned X-Wing extend X-Wings but it has extra candidates of X that prevent one of the two pairs normally required. Eliminations are still possible in this fin.

Unit Forcing Chains
Date Created: Saturday 6-Mar-2010
Last Updated: Sunday 29-Mar-2015
Sudoku Strategy. This is a Forcing Chains Strategy. It finds eliminations by comparing the results of chains starting with all candidates N in a unit and assuming any of them are turned on.