The same rules as for Rainbow Killer 4
Rainbow as in "All the numbers in the rainbow"
The numbers are from 0-9
There is a zero in every nonet, row and column. Zero is chosen as it increases the killer combinations.
Each other number is missing from one and only one nonet, row and column.
I tried to do 5.5 and failed miserably, so I simplified it and still failed. So I simplified it further. Once I succeeded on 5.1, I slowly built up and eventually solved 5.5.
You may follow my increasing difficulty path, or you may wish to go straight to 5.5.
Rain K5.1
Rain K5.2
Rain K5.3
Rain K5.4
Rain K5.5
