Excel is well known as an environment in which you can create models. Many modellers secure the integrity of their model by a combination of protecting and/or hiding sensitive cells. This is understandable when the model becomes the live or final version. Nevertheless, I have railed against using Excel in this way for 3 decades but have failed to convince colleagues. Using Excel to model solution methods in Sudoku is intended to demonstrate why it is such an excellent environment for exposing the strengths (and weaknesses) of any particular solution method. I concentrate here on two very similar methods referred to as “Intersection”. Background I have published a number of blogs / articles covering the more straightforward elements of users interacting with their Sudoku puzzles. This article builds on the previous publications. Title Source Date Spatial Modelling Techniques in Microsoft Excel EuSpRIG 14th Annual Conference, Greenwich July 20