The clue represents the sum of the numbers in the adjacent
block of empty cells
The numbers 1 to 9 are used to fill the grid
Each block may contain only one occurrence of a digit
So how is it solved? If you've come from sudoku, then you
have a head start. You will be using logic to seek out individual
numbers and you will be keeping track of "candidate" numbers in each
cell, just as you would in sudoku.
Candidates are the possible numbers that can go in cells. For
example, in a block of two empty cells, where the clue is 3 both
cells will have candidates of 1 and 2. With these small clues you
may see the solution straight away, but if not, you should note the
candidates in the cells.
It will have already become apparent that there is only one
possible combination for the solution to the clue 3: 1 and 2. The
same goes for 4 in two cells, which is 1 and 3. The clue 10 for a
four-cell block will produce 1, 2, 3 and 4 - no other combination
will work - and there are many more examples like these.
Combinations where there is only one outcome are very important to
kakuro solving and I have included
a table of them.
