

Basic Solving Sudoku Technique


Elimination by Mensa Guide to Solving Sudoku


Below is an example of using Elimination (a.k.a. Hidden Single, or Loner) to fill R4C3 (the square in the fourth row and the third column).Medium Sudoku on 03/13/2018 

Solve medium Sudoku on 03/13/2018 in a stepbystep style  
For the fourth row,


For convenience, we call RowElimination: an untaken number in a row only show up in one empty square as its candidate values, then this empty square must take the number. ColumnElimination: an untaken number in a column only show up in one empty square as its candidate values, then this empty square must take the number. BoxElimination: an untaken number in a 3×3 box only show up in one empty square as its candidate values, then this empty square must take the number. 

How to find them?Scan numbers that have been taken by squares. For example, in the above example,




Basic Solving Sudoku Technique


Elimination by Mensa Guide to Solving Sudoku


Below is an example of using Elimination(a.k.a. Hidden Single, or Loner) to fill R4C3 (the square in the fourth row and the third column). 

Medium Sudoku on 03/13/2018


Solve medium Sudoku on 03/13/2018 in a stepbystep style  
For the fourth row,


For convenience, we call RowElimination: an untaken number in a row only show up in one empty square as its candidate values, then this empty square must take the number. ColumnElimination: an untaken number in a column only show up in one empty square as its candidate values, then this empty square must take the number. BoxElimination: an untaken number in a 3×3 box only show up in one empty square as its candidate values, then this empty square must take the number. 

How to find them?Scan numbers that have been taken by squares. For example, in the above example,




