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:
“A man’s desire for a son is usually nothing but the wish to duplicate himself in order that such a remarkable pattern may not be lost to the world.”
—Helen Rowland (1875–1950)
“Let man consider what he is in comparison with all existence; let him regard himself as lost in this remote corner of nature; and from the little cell in which he finds himself lodged, I mean the universe, let him estimate at their true value the earth, kingdoms, cities, and himself. What is a man in the infinite?”
—Blaise Pascal (1623–1662)
“Unlike the ambiguity of life, the ambiguity of language does reach a limit.”
—Mason Cooley (b. 1927)