Latest Changes and Additions

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

3D Medusa
Date Created: Saturday 6-Mar-2010
Last Updated: Friday 23-Oct-2026
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.

Tridagons
Date Created: Friday 19-Sep-2025
Last Updated: Monday 19-Oct-2026
The Tridagon or Thor's Hammer is a Sudoku strategy discovered by Denis Berthier

What's New
Date Created: Monday 17-Aug-2009
Last Updated: Monday 19-Oct-2026


Unique Rectangles
Date Created: Friday 11-Apr-2008
Last Updated: Thursday 15-Oct-2026
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 they are explained here.

Sudoku Solver - Version History
Date Created: Sunday 13-Apr-2008
Last Updated: Thursday 3-Sep-2026


Simple Colouring
Date Created: Saturday 29-Jan-2011
Last Updated: Saturday 4-Jul-2026
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.

Rectangle Elimination
Date Created: Saturday 7-Oct-2023
Last Updated: Thursday 2-Jul-2026
A new tough strategy by Ken Reek

Intersection Removal
Date Created: Thursday 3-Apr-2008
Last Updated: Monday 22-Jun-2026
Sudoku Strategy. Pointing Pairs and Box Line Reduction are two Intersection Removal strategies used to eliminate candidates in the boxes that intersect the row or column that the formation lies on.

Naked Candidates
Date Created: Thursday 9-Jun-2005
Last Updated: Monday 8-Jun-2026
Sudoku Strategy. Naked Pairs, Triples and so on - these are the remaining candidates left in cells aligned on a row, column and box which can be used to remove other candidates the formation is aligned with.

Cell Forcing Chains
Date Created: Saturday 6-Mar-2010
Last Updated: Sunday 7-Jun-2026
Sudoku Strategy. This is a Forcing Chains Strategy. It finds eliminations by comparing the results of two chains starting with a bi-value cell assuming either candidate in the cell is turned on.