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Arctic Sudoku
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ExpertKiller

Cage splitting

What it is

Split a cage that crosses boxes and use the 45 rule to find the sum of each part.

How to spot it

Find a cage that lies partly in a box where all other cages are known. The 45 rule gives the part inside; the rest of the cage is the remainder.

Example

1231234565101620
  • Basis
  • Second colour
  • Removed / placed
The cage of 20 crosses from box 1 into box 2. The other cages in box 1 total 5 + 10 + 16 = 31, so r1c3 + r2c3 = 14. The part in box 2, r1c4 + r2c4, is 20 − 14 = 6.

Used from level: Expert (Killer Sudoku)