- ➊ Write a number between 1 and 9 into each white cell so that
eachnumber occurs exactly once in each row and column.
- ➋ The sum of the numbers in a stripe of horizontally or
vertically adjacent white cells is given (just like the definitions in a
- ➌ The difference between the numbers in two cells separated
by a circle must be exactly one; the difference between the numbers in two
not separated by a circle must not be exactly one.