Little Killer Sudoku Explained in One Short Example
A clue of 12 points along the long diagonal of a 3x3 grid. The digits 1, 5 and 6 add up to 12, and digits may repeat on a diagonal when the rest of the grid allows.
Transcript
The rule
Little killer sudoku puts small clues with arrows outside the grid. Each clue is the sum of every cell on the diagonal the arrow points along.
A diagonal's cells never share a row or column, so digits can repeat on it as long as the matching cells sit in different boxes. Cells of the diagonal inside one box still can't match.
Worth memorizing
Digits can repeat on a little killer diagonal, unless another rule stops them.
Short diagonals near corners are the easy starting points.
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