1)   Royal Sudoku 1.0
A complicated version of sudoku game destined for real kings of puzzles. Rules are simple. Each row, column and subgrid inibox (4x4) comprises the numbers 1 through 16 or letters A through P or anything else.
royal, 16x16, Suduko, Sudoko, Su do ku, Sodoku, Suduku, Sudoku, Solver, Suuji wa dokushin ni kagiru,