After initial hard to come by breakthroughs, the very hard Sudoku game 38 finally solved by repeated X wing reduction of possible digit.
Sudoku hard game 37 is solved by advanced Sudoku solution techniques of double digit scan, parallel scan, Cycles and naked cell by digit subset reduction.
Sudoku hard game 36 is solved by advanced Sudoku solution techniques of double digit scan, parallel scan, and naked cell by long digit subset reduction.
After initial hard to come by breakthroughs, the very hard Sudoku 35 finally solved by linked locked digit pair analysis and test of invalid choice.
Sudoku hard level 4 game 34 solved by Sudoku hard solution techniques. Persistent use of single digit lock and other patterns provided breakthroughs.
Sudoku hard level 4 game 33 solved by forming an X wing pattern of two pairs of digits sharing same two columns and rows for the critical breakthrough.
Very Hard Sudoku Level 4 Game 32 Solved by asymmetric X wing diagonal test. A pair of diagonally opposite locked digits are tested invalid for breakthrough.
Sudoku hard solution techniques are used with intensity and innovation to solve the Sudoku hard level 4 game 31 in easy steps.
Sudoku hard solution techniques are used with intensity and innovation to solve the Sudoku hard level 4 game 30 in easy steps.
Very Hard Sudoku Level 4 Game 29 Solved by X wing diagonal test. One pair of locked digits placed diagonally opposite are tested invalid for breakthrough.
