See also the small variant based on sums - click here
or on MiniSum above.
In standard SUDOKU
puzzles (as on the left),
the aim is to place the digits from 1 to 9 in each small square so each row, column and 3x3 mini-array
(surrounded by bold lines) contains each digit just once.
With Sudoku-X puzzles
, it is also
required that each main diagonal contains each digit just once. A 'correct'
Sudoku-X will not be soluble unless use is made of the additional diagonal requirements (i.e. you will not
be able to fill it in fully if you treat it like a standard Sudoku).
page lists collections of both types of puzzles.
page offers a free Windows-compatible Player program for Sudoku/-X
puzzles, as well as downloads of the puzzles featured here.
I also set Killer Sudoku
(which, despite the name, are not necessarily difficult!). These involve Sudoku grids in
which no squares are pre-filled in but in which meshes are used to surround given areas, the
sum of all contained square values being indicated.