

Solving Sudoku  Last Resort


Guessandcheck, nishio (Japanese name) by
Mensa Guide to Solving Sudoku
, and


ConflictElimination: Try each candidate value for a blank square. If the tried number of a blank/empty square leads to a conflict, you can safely remove this number from the blank/empty square. 

A conflict occurs when a blank/empty square has empty candidate values. 

Note that when our solver (solver used in this website) checks whether a guess will lead to a conflict, only basic methods (OneChoice, Elimination) and advanced methods (Interaction, Subset, SubsetPosition, XWing, XYWing, XYZWing) are used. 

Exhaustive search in our solver means trying every possible number assignments for remaining blank squares.  
R1C3 = 8 leads to a confliction where R2C6 has empty candidate values. Here is how it leads to a confliction. R1C3=8 → R1C4 = 1 → R4C4 = 4 → R4C7 = 1 → R5C9 = 4 → R3C9 = 1 → R2C8 = 4 → R2C5 = 3 → R2C6 = ∅ Remove number 8 from R1C3's candidate values. We get R1C3 = 1. 

Hard Sudoku on 03/25/2018  
Solve Hard Sudoku on 03/25/2018 in a stepbystep style  
How to find them?




Solving Sudoku  Last Resort


Guessandcheck, nishio (Japanese name) by
Mensa Guide to Solving Sudoku
, and


ConflictElimination: Try each candidate value for a blank square. If the tried number of a blank/empty square leads to a conflict, you can safely remove this number from the blank/empty square. 

A conflict occurs when a blank/empty square has empty candidate values. 

Note that when our solver (solver used in this website) checks whether a guess will lead to a conflict, only basic methods (OneChoice, Elimination) and advanced methods (Interaction, Subset, SubsetPosition, XWing, XYWing, XYZWing) are used. 

Exhaustive search in our solver means trying every possible number assignments for remaining blank squares.  
R1C3 = 8 leads to a confliction where R2C6 has empty candidate values. Here is how it leads to a confliction. R1C3=8 → R1C4 = 1 → R4C4 = 4 → R4C7 = 1 → R5C9 = 4 → R3C9 = 1 → R2C8 = 4 → R2C5 = 3 → R2C6 = ∅ Remove number 8 from R1C3's candidate values. We get R1C3 = 1. 

Hard Sudoku on 03/25/2018  
Solve Hard Sudoku on 03/25/2018 in a stepbystep style  
How to find them?





