Duplicate Cell Ambiguity
By convention in Japan, killer sudoku cages do not include duplicate numbers. However, when The Times first introduced the killer sudoku on 31 August 2005, the newspaper did not make this rule explicit. Even though the vast majority of killer sudoku puzzles followed the rule anyway, English-speaking solvers scratched their heads over appropriate solving strategies given the ambiguity. On September 16, 2005 The Times added a new ruling that “Within each dotted-line shape, a digit CAN be repeated if the normal row, column and 3x3 box rules are not broken”. But on September 19 the rule changed to “Within each dotted-line shape, a digit CANNOT be repeated if the normal row, column and 3x3 box rules are not broken” - causing even more scratching of heads. This revised rule stuck and the world standard is no duplicates within cages.
Read more about this topic: Killer Sudoku
Famous quotes containing the words duplicate, cell and/or ambiguity:
“O Nature, and O soul of man! how far beyond all utterance are your linked analogies! not the smallest atom stirs or lives in matter, but has its cunning duplicate in mind.”
—Herman Melville (1819–1891)
“Women have no wilderness in them,
They are provident instead,
Content in the tight hot cell of their hearts
To eat dusty bread.”
—Louise Bogan (1897–1970)
“Indeed, it is that ambiguity and ambivalence which often is so puzzling in women—the quality of shifting from child to woman, the seeming helplessness one moment and the utter self-reliance the next that baffle us, that seem most difficult to understand. These are the qualities that make her a mystery, the qualities that provoked Freud to complain, “What does a woman want?””
—Lillian Breslow Rubin (20th century)