A Latin square is simply a grid of numbers from ... meaningfully different 9-by-9 sudoku puzzles. That’s a huge number, but not nearly as huge as the number of Latin squares.

Sudoku puzzles, in which a solver tries ... 9 x 8 x 7 x 6 x 5 x 4 x 3 x 2 x 1, since we have 9 digits to choose from for the first square, leaving 8 choices for the second square, then removing ...

But even the most dedicated Sudoku ... this square away, the same number is removed from both and so the sets will still be identical. For example, if the central square is the number '9', then ...

Competitors at the World Sudoku and Puzzle Championships ... insert a number from 1 to 9 into each cell so that no number repeats in any row, column or bolded 3-by-3 square region.