Daily 16×16 Giant Sudoku Puzzle (Hard) - PuzzleMadness
https://puzzlemadness.co.uk/16by16giantsudoku/mixed
WEBHow to play. This is an example of a 16x16 Sudoku. They are very similar to standard 9x9 Sudoku puzzles, but instead of using the number 1-9, we use the numbers 1-9, and also the letters A, B, C, D, E, F, and G. Each row, column, and 4x4 region must be contain one and only one of these.
DA: 98 PA: 58 MOZ Rank: 19