Sudoku Sam 
MODUS FORTIS Sudoku Logic, Sudoku Reason [EPUB ebook] 

Modus Fortis represents a Khunian shift in Sudoku strategy. Using just four basic tactics that give rise to just two molecular structures–Doubles and Pairs–that evolve into just two Families of complex structures (Exclusive Sets and Forbidden Sets) is all that is needed to solve every Sudoku. But just as E = mc2 is easy to visualize, there is a bit more to understanding the equation. The logical principle that drives the Solution Process is the Exclusive Disjunction: the Modus Fortis. This, combined with the Pairing Principle, guides the Sudoku-ka through the process of constructing a Solution from emerging Sets of Digits, identifiable as structural patterns. A concise notation system allows for recording every significant event in the Solution Process, just as in chess. Richly illustrated, this is a readable book for all levels of interest.