#4497, July 23: Competition Killer Sudoku Puzzle - Diabolical level of difficulty
Welcome to the Daily Sudoku Competition. The rules are
simple, just print out the Sudoku from the link below and when you have
completed it enter the numbers in the graphical sudoku board (yes it's a form!).
You need to enter your name, email address and country. If this is your first time
then it will automatically create a personal history for you so you can keep track of your
submissions and try for the Experts list. Anyone can get into the Top Sudoku Expert list- this is now the sum of all your correct entries for the
last three hundred and fifty days. Read the Web Site Update announcement for the update on submitting.
The competition cut-off time is midnight EST (GMT-5) and 5:00am (GMT) UK Time.
Killer Sudoku is a fiendish variant of Sudoku - the same 9 x 9 board with rows,
columns and nine boxes that must be filled in with all the numbers 1 to 9. But
instead of seeing some starter clues where some cells are completed for you, in
killer sudoku areas of the grid are "caged". Each cage contains a single number
which is the sum of all the solutions in that shape. You have to use this
information to crack the Sudoku, but all the normal strategies of Sudoku still
Anyone who has tried Kakuro will see a connection. A cage of two
cells containing a target of 3 will must contain cells with the value 1 and 2.
(We conform to the Killer convention that no cage will contain a duplicate
number even if it is within the rules of sudoku).
Killers strategies are explained on our forum here and on this external site here.
A list of Cage/Value combinations is available here.