The very hard expert Sudoku level 5 game 13 is solved step by step by advanced Sudoku techniques and the breakthrough of X wing digit reduction effect.
After initial hard to come by breakthroughs, the very hard Sudoku game 38 finally solved by repeated X wing reduction of possible digit.
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.
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.
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.
Very hard Sudoku level 4 game 24 solved by test of linked pairs of locked digit chains resulting in conflict of same digit in two cells of same column.
Very hard Sudoku level 4 game 23 solved by test of linked pairs of locked digit chains resulting in conflict of same digit in two cells of same column.
Very hard Sudoku level 4 game 22 solved by analysis of linked pairs of locked digit resulting in conflict of same digit in two cells of same column.
Very hard Sudoku level 4 game 21 is solved step by step using valid diagonal test of an asymmetric X wing digit formation for easy understanding.
Very hard Sudoku level 4 game 20 is solved step by step using advanced Sudoku techniques and strategy so that it is easy to follow how to solve hard Sudoku.
