External cue Sudoku rule?

External cue Sudoku is not a kind of Sudoku, but a big category of Sudoku.

The most common and classic problem of Sudoku is Sudoku in skyscrapers. I guess that's what you want to ask, see the picture below.

There are also n kinds of calculations, such as the sum of Sudoku X and Z, and directional Sudoku determines which Sudoku is not a number.

Please click to enter a picture description.