The canonicalization is based grids, then Sudokus that fit the grid. Digits ordered from 1 through 9. For each grid, Sudokus are ordered from fewest clues to most clues. For Sudokus with the same number of clues, clues are ordered based on positions of the clues; from top to bottom, then left to right. Again, digits are ordered from 1 through 9, and canonicalized based on the numbers in the top row first, and then in cells from left to right. I notice this Sudoku by Rico Alan (rotated and rows re-ordered compared to how he posted it):

- Code: Select all
`1234.....`

.....3456

.........

2345.....

.....4567

.........

3456.....

.....5678

.........

Based on the proposed canonicalizing scheme, can we say that this is the first Sudoku? If not, then what is the first Sudoku? Also, how many more Sudoku's will there be in the complete list?